Electrical Engineering Pre-Board Compilations
(2012-2018)
\
AUGUST 2012
1. A coil has a 50 ohms resistance and a 70 ohms reactance. A capacitor is
connected in parallel to produce resonance. The source voltage is 120 V. What is
the power drawn by the circuit?
A. 162 W
B. 132 W
C. 97 W
D. 52 W
2. Two electrons in a vacuum experience a force of 2 x 10 -15 N. How far apart are
the electrons?
A. 3.4 x 10-7m
B. 9.6 x 10-7m C. 2.84 x 10-12m
D. 5.05 x 10-12m
3. The pitch factor for third harmonic in an alternator having 18 slots per pole and
coil span 5/6 of pole pitch is _.
A. 0.707
B. 0.259
C. 0.966
D. 1
4. When two capacitors of reactances 10ohms and 20 ohms are connected in
parallel across a 100 V supply, total VAR drawn will be _.
A. 500
B. 2
C. 1,500
D. 15
5. Overvoltage relay device function number.
A. 64
B. 56
C. 60
D. 59
6. A test used to determine the equivalent resistance of an induction motor is _.
A. No-load Test B. Short-circuit Test C. Blocked-rotor Test D. Polarity Test
7. A transformer has 4% resistance and 6% reactance drop. What is the voltage
regulation at full load 0.8 pf lagging?
A. 6.0%
B. 6.4%
C. 6.8%
D. 7.2%
8. The unit of retentivity is
A. Ampere turn B. ampere turn/weber C. ampere turn/meter D. dimensionless
9. Three 10 ohm resistances are connected delta on a balanced three phase
source. If the equation of the phase Van = 120 sin ωt, what is the equation of the
phase a line current?
A. 36 sinωt
C 11 22 sin ωt 30
B. 13 15 sin ωt - 30)
D 11 88 sin ωt -56.6)
10. A 250/6,600 V, 50 Hz single – phase transformer has a core of cross section 600
cm2 and the flux density in it is 0.707 Tesla. Determine the number of turns in the
primary winding.
A. 27
B. 19
C. 23
D. 17
11. In running condition the rotor reactance of 3Φ induction motor is proportional to
A. induced emf
B. slip
C. supply voltage D. rotor resistance
12. The ratio of the total flux to useful flux is called _.
A. Mutual flux B. Flux Factor C. Leakage Factor D. Magnetic Factor
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
13. An electric motor converted 700 W of electrical input into work at 58.186 kg-m/s.
The speed was 1750 rpm. Find the kg-m of driven torque.
A. 0.183
B. 0.381
C. 0.138
D. 0.318
14. What is the annual capacity factor of the plant if the annual energy produced in a
150 MW power plant is 500 x 106 kWhr?
A. 56.785%
B. 34.44%
C. 44.04%
D. 38.05%
15. With reduction of load on alternator
A. the frequency decreases
C. the frequency oscillates
B. the frequency increases
D. the frequency remains the same
16. What is the quality factor Q of an RLC series circuit having R = 5 ohms, L = 10
mH and C = 100μF?
A. 2
B. 5
C. 10
D. 20
17. A load of 10, 000 kVA, 80% lagging is connected to a 13, 200 V line. How much
capacitive reactive power is needed to correct the power factor to 97% lagging?
A. 3, 995 kVAR B. 3, 138 kVAR C. 5, 156 kVAR D. 2, 547 kVAR
18. Two No. 8 copper conductors are placed 15 cm apart with a GMR of 1.27 x 10 -3
m. If the length of the line is 4 km, find the value of the line inductance.
A. 5.78 mH
B. 6.85 mH
C. 7.63 mH
D. 9.65 mH
19. The process by which metallic parts are demagnetized is called
A. degreasing
B. degaussing C. degrading D. demagnetizing
20. The gas inside the inner discharge tube of a sodium vapor lamp is
A. Argon
B. Neon
C. Nitrogen
D. Helium
21. The following are the symmetrical components of phase B current:
Positive Sequence Component = 10 cis 45
Negative Sequence Component = 20 cis -30
Zero Sequence Component = 0.5 + j0.9
Determine the positive sequence component of Phase A.
A. 20 cis -195
B 10 cis 195
is D 10 cis -30
22. What is the force between two wires carrying currents 10 and 50 A each? The
lengths of the wires are 50 cm and are separated by 5 cm distance.
A. 0.005 N
B. 0.002 N
C. 0.001 N
D. 0.004 N
23. What is the nature of the current flowing in the armature of DC machine?
A. pulsating dc
B. pure dc C. rectified dc D. alternating current
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
24. Which of the following frequencies has the longest period?
A. 1 Hz
B. 10 Hz
C. 1 kH
D. 100 kHz
25. Two coils of inductance 8 H and 10 H are connected in parallel. If their mutual
inductance is 4H, determine the equivalent inductance of the combination if
mutual inductance assists the self- inductance.
A. 3.46 H
B. 2.46 H
C. 4.6 H
D. 6.4 H
26. The voltage applied to the stator of a three phase, 4 pole induction motor has a
frequency of 50 Hz. The frequency of the emf induced in the rotor is 1.5 Hz.
Determine the speed at which motor is running.
A. 1, 450 rpm
B. 1,455 rpm
C. 1, 460 rpm
D. 1,465 rpm
27. If one of the resistors in a parallel circuit is removed, what happens to the total
resistance?
A. Decreases B. increases C. exactly doubles D. remains constant
28. What is the purpose of using oil in the transformer?
A. insulation
B. cooling C. cooling and insulation
D. lubrication
29. An air capacitor consists of two parallel square plates of 60 cm side. When the
two plates are 2 mm apart the capacitor is charged to a voltage of 240 V.
Determine the work done in separating the plates from 2 mm to 5 mm.
A. 27 4 μJ
B 24 75 μJ
C 25 74 μJ
D 42 75 μJ
30. Skin effect is proportional to
A. ( diameter of conductor )2
B. diameter of conductor
C. ( diameter of conductor )3
D. ( diameter of conductor )1/2
31. A balanced delta connected load of ( 4 + j3 ) ohms per phase , 230 V supply.
Find the total kVA.
A. 19.04 kVA
B. 37.01 kVA
C. 31.74 kVA
D. 25.39 kVA
32. A 400 V, 10 kW series motor drives a fan when running at 800 rpm. The motor
draws 50 A from the supply. The resistances of the armature and series field are
0.2 ohms and 0.1 ohms, respectively. Determine the electromagnetic torque
developed by the motor.
A. 215 N-m
B. 220 N-m
C. 225 N-m
D. 230 N33. The three primary colors in the chrominance signal of a color TV are
A. red, green, orange
C. blue, green, magenta
B. red, green, blue
D. yellow, green, cyan
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
34. An alternator running in parallel with the other alternators all having automatic
voltage regulators is to be taken off the bus. The usual procedure before opening
the switch is to
A. reduce alternator excitation
C. reduce the power fed to the prime
mover
B. increase alternator excitation D. do nothing
35. In a 4 pole, 35 slot, dc armature, 180 electrical degrees coil span will be obtained
when coils occupy _ slots.
A. 1 and 10
B. 1 and 9
C. 2 and 11
D. 3 and 12
36. A circuit which has ω0 = 106 rad/sec, C = 10 pF and Q = 100, must have a
resistance of _ kῼ.
A. 10
B. 5
C. 1
D. 100
37. A lamp produces an illumination of 10 lux at a point 10 m directly below it. What
is its luminous intensity?
A. 100 Cd
B. 10 Cd
C. 10, 000 Cd
D. 1, 000 Cd
38. A lead acid battery having a 100 Ah capacity is 25% charged. After being
charged at 10 A for 5 hours, it will be approximately _ charged.
A. ½
B. ¾
C. fully
D. over
39. Four 100 W, 100 V heaters are connected in series across a 600 volt circuit. The
total heat given off by the four heaters will be _ watts.
A. 900
B. 800
C. 400
D. 2000
40. Which one of the following is not one of the relays of transmission line?
A. Phase comparison relay
C. Distance relay
B. Negative sequence relay
D. Ground relay
41. In an electric system the available short circuit MVA is 600 MVA. What is the
Thevenin’s equivalent reactance at 34 5 kV?
A. 1.984 ῼ
B. 1.587 ῼ
C. 2.561 ῼ
D. 0.046 ῼ
42. The area of hysteresis loop is the measure of
A. permittivity B. permeance C. energy loss per cycle D. magnetic flux
43. If the secondary terminals of a 5:1 stepdown transformer is connected to the
primary of a 2:1 stepdown transformer then the total stepdown ratio of both
transformers is
A. 2.5 : 1
B. 3 : 1
C. 10 : 1
D. 7 : 1
44. Slip rings are made of
A. Steel
B. Copper
C. Bakelite
D. Mica
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
45. In a winding of a 3Φ, 6 pole induction motor, the space angle between two
consecutive phases is
A. 600 mech.
B. 1200 mech.
C. 1800 mech.
D. 400 mech.
46. The tailwater and the headwater of a hydro- electric power plant are 150 m and
200 m, respectively. What is the water power if the flow is 15 m 3/sec and a head
loss of 10% of the gross head?
A. 4, 621.56 kW
B. 7, 621.65 kW
C. 5, 621.76 kW D. 6, 621.75 kW
47. A 2,000 V/ 400 V single phase transformer has an equivalent resistance of 0.03
pu and an equivalent reactance of 0.08 pu. Find the full load voltage regulation at
0.8 pf lagging if the primary voltage is 1,500 V.
A. 6.6%
B. 6.8%
C. 7%
D. 7.2 %
48. Determine the value of R for which power consumed in it is maximum when it is
connected in series with a coil of resistance 3 ῼ and reactance 20 ῼ across 230
V, 60 Hz AC supply.
A. 20 ῼ
B. 3 ῼ
C. 6.67 ῼ
D. 20.22 ῼ
49. Moving coil instruments are used
A. In ac circuits only
B. In dc circuits only
C. Both in ac and dc circuits
D. For measuring voltage only
50. The efficiency of thermal plant is approximately _.
A. 10%
B. 30%
C. 60%
51. Merz – Price protection is used on
A. Substations
B. Capacitor Banks C. induction motors
D. 80%
D. Generator
52. A balanced delta connected load draws 100 A line current from a balanced 3
phase supply. Determine the zero sequence components of the currents.
A. -50 – j86.6
B. 50 – j86.6
C. 0
D. 86.6 + j50
53. Impedance z1 = 10 + j15 ohms and another impedance z2 = 6 – j8 ohms are
connected in parallel across a 60 Hz source. Find the total power in watts if the
total current is 15 A.
A. 1,845 W
B. 2,176 W
C. 3,188 W
D. 2,380 W
54. A magnetizing force of 1000 AT/m will produce a flux density of _ in air.
A. 0.63 mWb/m2 B. 0.63 Wb/m3 C. 1.257 mWb/m3 D. 1.257 Wb/m3
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
55. A 13 8 kV distribution line has a Thevenin’s equivalent impedance 2 63% If a
phase to phase fault occurs between phase B and C, determine the fault current
at 10 MVA base.
A. 13,000 A
B. 7,950 A
C. 5,300 A
D. 15,900 A
56. A transmission line has two aluminum conductors in bundle. The self GMD of
each conductor is 8.90 mm and the distance between the conductors and phase
is 40 cm and 9 m, respectively. What is the inductance of the line per phase?
A. 2 μH/m
B 4 μH/m
μH/m
D 3 μH/m
57. The greater percentage of materials are _ .
A. Diamagnetic B. Paramagnetic C. Ferromagnetic D. Non- magnetic
58. The electric potential at appoint in air due to a charge is 21 V. If air is replaced by
a medium of relative permittivity of 3, then the electric potential at that point will
be _ .
A. 63 V
B. 7 V
C. 21 V
D. 42 V
59. The greatest percentage of power loss in dc motor is due to
A. Windage loss B. Core Loss C. Copper Loss
D. Friction Loss
60. A galvanometer with a 20 ohms coil resistance has a full scale deflection of 10
mA. A 0.02 ohm is placed across the meter to increase its rated capacity. What is
the new full scale current for the meter?
A. 100.1 A
B. 1.01 A
C. 10.10 A
D. 10.01 A
61. A 3Φ, 6 pole, 50 Hz induction motor develops 3 73 kW at 960 rpm. What will be
the stator input if the stator loss is 280 watts?
A. 4,615 W
B. 4,165 W
C. 3,855 W
D. 4,516 W
62. Calculate the average voltage generated in a six turn full pitch coil of a 60 cycle
alternator if the flux per pole is 7.2 x 10 5 maxwells.
A. 4.32 V
B. 23.4 V
C. 17.30 V
D. 10.37 V
63. The charge of a hole is _.
A. Zero
B. Equal to that of a proton
C. equal to that of an electron
D. equal to that of a netron
64. Transient current in an RLC circuit is oscillatory when
A. R = 0
B. R = 2 sq.rt. L/C
C. R > 2 sq.rt. L/C
D. R < 2 sq.rt. L/C
65. Three units of 1:5 transformers are connected in Δ/Y to supply a 3 phase load
from a 480 V, 3 phase source. The line voltage on the load side is _ volts.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 2,400 V
B. 832 V
C. 4,160 V
D. 1.386 V
66. As load pf of an alternator becomes more leading, the value of the generated
voltage required to give rated terminal voltage _.
A. Decreases B. Increases C. Remains constant D. Varies with rotor speed
67. This device is used to reflect back surges into the line.
A. Deion gaps B. Overhead Ground C. Choke Coil
D. Arc Horns
68. Some of the arrangement for switch/panel boards are as follows, except _.
A. Vertical
B Linear
C. Semi – Circular D. Truck Type
69. A 220 V, 3 phase, 4 wire abc system supplies unbalanced wye connected
resistances of Ra = 10 ohms, Rb = 15 ohms, and Rc = 20 ohms. Determine the
total power of the system.
A. 3, 495 W
B. 3,385 W
C. 3,560 W
D. 3,895 W
70. If a 440 V heater is used on 110 V supply, heat produced by it will be as _ much.
A. ¼
B. 4 times
C. 16 times
D. 1/16
71. A complex current wave is represented by the equation i = 5 5sin 120π t A
Find its average value in amperes.
A. 4.5
B. 6
C. 5
D. 4
72. The fuse used for the overhead primary distributors is
A. Fast acting
B. Dual Element
C. Expulsion
D. Cartridge
73. A transformer has a maximum efficiency of 95% at a load of
constant loss of the transformer?
A. 6. 32 kW
B. 3.26 kW
C. 3.62 kW
74. A string of four insulators has a self-capacitance equal to 5
capacitance. Find the string efficiency.
A. 64.86%
B. 66.48%
C. 68.64%
100 kW. What is the
D. 2. 63 kW
times of pin to earth
D. 84.66%
75. Porcelain insulators are protected against creepage of surge current by the use
of _.
A. Surge gaps B. Arcing Horns C. Ground Conductors D. surge arrester
76. An amplifier works best into an impedance of 500 ohms but is required to drive a
speaker of 20 ohms impedance. The primary to secondary turn ratio of the
matching transformer should be
A. 1/5
B. 25
C. 5
D. 1/25
77. The rms value of the complex voltage given by v = 16 sq.rt 2 sin ωt
sin 3ωt is
12 sq rt 2
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 20 sqrt 2 V
B. 20 V
C. 28 sqrt 2 V
D. 192 V
78. A uniform 2 wire dc distributor 500 meters long is loaded with 0.4 ampere/meter
and is fed at one end. If the maximum permissible voltage drop per wire is not to
exceed 10 V, find the cross-sectional area of the distributor Take ρ = 1 7 x 10-6
ῼ-cm.
A. 1.0 cm2
B. 1.2 cm2
C. 1.5 cm2
D. 1.7 cm2
79. This is a lighting system wherein the percentage of upward and downward
brightness is the same.
A. General Diffuse
B. Direct
C. Indirect
D. Semidirect
80. A coil having a resistance of 10 ohms and an inductance of 15 H is connected
across a dc voltage of 150 V. When the supply is switched off, find the time for
the current to drop to 9 A.
A. 0.667 sec
B. 0.607 sec
C. 0.706 sec
D. 0.766 sec
81. An iron ring 100 cm mean circumference is made from around iron of cross
section 10-3 m2. Its relative permeability is 500. If it is wound with 250 turns, what
will be required to produce a flux of 2 x 10-3 Wb?
A. 21.47 A
B. 14.27 A
C. 12.74 A
D. 17.42 A
82. An 8 pole lap wound dc generator has 1000 conductors in its armature. The flux
produced per pole is 20 mWb and emf generated is 400 v. What is the speed of
the machine?
A. 1160 rpm
B. 1200 rpm
C. 1240 rpm
D. 1300 rpm
83. Power in a balanced 3 phase system is measured by two wattmeter method and
it is found that the ratio of the two wattmeter readings is 2 is to 1. What is the
power factor of the system?
A. 0.9
B. 0.82
C. 0.866
D. 0.707
84. One ampere-turn is equivalent to _ gilberts.
A. 1.16
B. 1.26
C. 1.36
D. 1.46
85. What value of R is needed with 0 05 μF capacitor for an RC time constant of 0 02
sec?
A. 400 ῼ
B. 400 kῼ
C. 400 Mῼ
D. 400 Gῼ
86. Which motor is used to start heavy loads?
A. Series
C. Cumulative Compound
B. Shunt
D. Differential Compound
87. The capacitor in a capacitor start induction run ac motor is connected in series
with _ winding?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. Compensating
B. Squirrel Cage
C. Starting
D. Running
88. A 150 MVA, 13.8 kV, Y- connected, 3Φ, 60 Hz alternator is operating at rated
voltage and at no load when a three phase fault occurs at its terminals. If the
subtransient reactance of the alternator is j0.2 pu , calculate the current at the
instant the fault occurs.
A. 10 460 A
B. 18 117 A
C. 6 040 A
D. 31 380 A
89. What is the total energy generated by a station in kWhr in a year if its maximum
demand and annual load factor is 150 kW and 45%, respectively?
A. 513,900 kWhr B. 531,900 kWhr C. 593,100 kWhr D. 591,300 kWhr
90. Power circuit breakers can be classified according to operation, some of these
are, except
A. Inclined Break B. Horizontal Break C. Gravity Open D. Gravity Close
91. The lowest KAIC available commercially for miniature circuit breakers is
A. 3
B. 5
C. 10
D. 14
92. A 100 km transmission line has a 1000 ohms shunt capacitive reactance. What is
the capacitive reactance per km?
A. 1000 ῼ
B. 10 ῼ
C. 100 000 ῼ
D. 100 ῼ
93. The shaft power of a shunt motor is 7.8 HP. Its armature draws 50 A from 120 V.
The field winding draws 1.2 A. What is the efficiency of the motor?
A. 94.7%
B. 96.5%
C. 93%
D. 98.2%
94. This is the least prevalent shunt fault among transmission and distribution lines.
A. LG
B. LL
C. LLG
D. LLL
95. In what year was the first 500 kV line in the world became operational?
A. 1936
B. 1953
C. 1965
D. 1969
96. A single phase transformer is rated 110/440 V, 2.5 kVA. Leakage reactance
measured from the low tension side is 0.06 ῼ. What is the leakage reactance in
per unit?
A. 0.0124
B. 0.0142
C. 0.0241
D. 0.0421
97. The rms value of a half wave rectified current is 10 A. Its value for full wave
rectification would be _ amperes.
A. 20
B. 14.14
C 20/π
D 40/π
98. If starting voltage of a SCIM is reduced to 50% of its rated vlue, torque developed
is reduced by _ percent of its full load value.
A. 57.7
B. 50
C. 25
D. 75
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
99. A standard candle emits a total luminous flux of _ lumens.
A. 157.90
B.78.96
C. 25.14
D. 12.57
100.
A generator of 50 MVA, 4kV, Xd” = 25% and transformer of 50 MVA, 4 2
kV, delta/115 kV wye grounded, operating on 3.8 kV tap where X T” = 10% are to
be connected into single equivalent reactance. What is the single equivalent
reactance on a 100 MVA, 110 kV base?
A. j0.6039 pu
B. j0.6667 pu
C. j0.8241 pu
D. j0.8663 pu
SOLUTIONS:
1. YT = GL
GL =
RL
ZRL
2
RL
=
RL
2
XL
2
=
50
50
2
702
GL = 0.00676 mho
PT = ET2VT2 = (1202)(0.00676) = 97.344 W
2. F=
kQ1 Q2
2
d
kQ1 Q2
;d=√
F
=√
(9x109 )(1 609x10-19 )
2x10
3. kp=sin (90)x pitch
18 slots/pole
5/6 pole pitch
5 1
kp= sin (90x x x18* = 7 7
6 2
4. X=
(10) 20
10 20
Qr =
5. D. 59
-15
= -j6 667
1002
=1499 23 VARS
j6 667
2
= 4
-7
m
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
6. C. Blocked-rotor Test
7. Rpu = .04
Xpu = .06
@
2
VR=√(Rpu pf) Xpu rf
1
2
8)2
=√( 04
2
06 6 -1
%VR= 6.97 % = 6.8%
8. B. ampere turn/weber
9. ZY= A
AB
B C
=
100
30
=
10
3
Van = 120 sinωt
Ian =
Van 120
=
=
10
Zy
3
sinωt
10. 250 / 6 600 V, 50 Hz
A= 600 cm2
β=0 707
E= 4.44fɸN
ɸ=βmA
E1 =4 44fβmAN1
N1 =
200
(4 44)(50) 707 600x10 4
=2
11. B. slip
12. C. Leakage Factor
13. T=
9 55 Pd
N
=
9 55 58 186
1750
=
-m
27
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
500 x106
Annual Energy in kWhr
14. PCF= Installed Capacity in kW x 8760 =
150 x103 8760
x 100%=
15. A. the frequency increases
1
L
1
10mH
16. Qfactor = R √C = 5 √100μF = 2
17. Q = PL tanθold –tanθnew) = (10000)(.8)(tan36.87 – tan 14.07) = 3995 kVAR
18.
d
15
L=4x10-7 ln (GMR) =4x10-7 ln (
-3
1 27 x 10
=7
) = (1 9086 x10-3 ) 4000m
mH
19. B. degaussing
20. B. Neon
21. F = (2x10-7)(I1)(I2)(1/D)
F = (2x10-7)(10)(50)(50/5) = .001N
22. C. rectified dc
23. 1 Hz
24. La =
25. Ns =
L1 L2 -M2
L1 L2
=
-2M
120 x 50
Ns =
4
(8 x 10)-42
8 10 -(2) 4
=
4H
=1500
4 1500 Nr
120
Nr = 1455 rpm
26. B. increases
27. C. cooling and insulation
28.
29. ( diameter of conductor )2
V
30. I= Z = 46 angle - 36 83
S=(462)(5)(3) = 31.74 kVA
31. Eb= VL –IP ( Ra + Rs) = 400 – 50( .1+.2) = 385
IL = Ia =Ise
Pd = EbIa = 385 x 50 = 19 250 W
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
T=
9 55Pd 9 55 19250
=
=2
N
800
m
32. red, green, blue
33. C. reduce the power fed to the prime mover
34. B. 1 and 9
1
35. XC = ωC =
R=
1
6
10
10X10-12
=100000
100000
=1000
100
=
36. I =10 lux
D=10 m
I=
L
d2
L=( 10 )(102 )=
37. Battery : 100 Ah, 25 % charged = 25 Ah charged
I = 10 A
t= 5 hrs
charged = (10 A) (5 hrs) = 50Ah
charged = 50 +25 =75 Ah
%charged =
38. P=100W
E=100V
Es=600V
1002
R=
=100
100
H=
V2 6002
=
=
4R 4x100
39. C. Negative sequence relay
40. S= 600 kVA
V= 345 kV
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
X=
41. C. energy loss per cycle
43. 5:1 = 2:1
(5)(2) = 1
10:1
44. B. Copper
45. 2 pole = 360
6 pole = 180
180
=60 mech
6
46. P=Qwh
h= 200 – 150 =50m
m=2x
Q=15m3/sec
HL=10%
P= 15x 9810 x 50 = (7357500) – (10%)(7357500) = 6621750
= 6621.75 kW
47. Pf=.8 lag
%R=.03pu
%X= .08pu
%VR=(Vpu cosθ Xpu sinθ)
Vpu cosθ Xpu sinθ
200
=[( 03)(cos36 87) ( 08)(sin36 87)]
7 22
48. R=√32 202 = 2 22
( 08)(cos36 87) ( 03) cos36 87
200
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
49. B. In dc circuits only
50. B. 30%
51. A.Substations
52. Ia = 100
Iab = 3In
Iab = 3 [(100angle0) + (100angle240) + (100angle120)]
Iab = 0
53. Z1 = 10 + j15 ῼ
Z2 = 6 – j8 ῼ
10 j15 6 j8
ZT =
10 j15 6 j8
ZT = 9.67 – j3 6
PT = (9.67)(152)
PT = 2176. 15 W
54. H=100AT/m
β=μrμoH = (91.26x10-6)(1000) = 1.257mWb/m2
10x106
S
55. IFL-L = VB =
B
13 8 x 103
=13 776 4
13 000 A
56. GMD= 8.90 mm
Ds1 = 40 cm
Ds2 = 9m
40
100
L1=2x10 ln (
) =7 61 x 10 7
8 90
1000
7
L2=2x10 7 ln (
8 90
1000
) =1 38 x 10 6
LT = L1 +L2 = 7 61 x 10-7 +1 38 x 10-6 =
57. B. Paramagnetic
μH/m
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
58. V=21V
Q=1.60x10-19
At k=3, V=?
V=
kQ
d
d=
9x109 1 6x10 19
21
d= 6.87x10-11
at k=3
V=
1 6x10 19
4π 0 (5) 6 87x10 11
=6 99 = 7
59. C. Copper Loss
60. Pg=20
Rsh= 02
Ig = 10mA
I = Ig x multiplier
multiplier=
Rg Rsh 20 02
=
Rsh
02
1001
I = 10 mA x 1001= 10.01 A
61. 3ø, 6pole, 50 Hz, Induction Motor
Pd = 3.73 kW @ Nr= 960 rpm
SL= 280W
Req’d : Ps
3 73x103
Pr =
=3885 42W
1 04
Ps = Pr + SL = 3885.42+280 = 4165.42 W
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
62. N=6 turns
f= 60 Hz
ø= 7.2x 105 maxwells
Eave = 4føN = (4)(60)(7.2x105)(x10-8) = 10.37 V
63. Equal to that of a proton
64. D. R < 2 sq.rt. L/C
65. a= 1:5
Δ/Y
VP=480 V
Vs = ?
Ep 1
=
ES/Q 5
ES/Q = (5)(4800)
ES/L-L = √3 2400 = 4156 9= 4160 V
66. A. Decreases
67. C. Choke Coil
68. A. Vertical
2202
69. PT = √3 10
PT =
2202
2202
√3 15
√3 20
6054 48
√3
=6054 48
= 4
70. VH = 440 V
VS = 110 V
Req’d: Heat Produced HH)
VH
VS
HH =
H
= HH
S
440HS
=4HS
110
4 times
71. i = 5 5sin(120π)t A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
iave =
IDC IAC 5 5
=
=
2
2
72. C. Expulsion
73. ɳmax = .95
PL= 100 kW
@ɳmax :Pcu = Pco
Req’d: Pco
100x103
100x103
Smax
95
ɳmax =
=
=2
Smax Pco
2
74. String efficiency =ɳst
v1 V2 V3
Vn
ɳst =
;k=1/5
n xVn
V2 = V1 (1 + k) = 1.2 V1
V3 = V1 ( 1 +3k + k2) = 1.64 V1
V4 = V1 (1 + 6k + 5k2 + k3) = 2.408 V1
V1 1 2V1 1 64V1 2 408V1
ɳST =
x100
4x2 408V1
ɳST = 64.867%
75. B. Arcing Horns
N1 2
Z
76. Z1 =
N2
2
=a2
500 2
=a =
20
77. V = 16√2 sinωt
Vrms =√Vdc
78. R=
V
I
12√2sin 3ωt
Vrms
2
2
2
Vrms √(16√2)
=
2
2
10
= 100 = 05
ρL
1 7 x10 6 50 000cm
R=
; 05=
A
A
A= 1.7 cm2.
2
2
12√2
=2
2
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
79. A.General Diffuse
80. R = 10 ohms
L = 15 H
E = 150 V
I=9A
@ switched off, t=infinity
E 150
I= =
=15 A
R 10
@ I= 9 A, t=?
I = 15 – 9 = 6 A
10
R
E
(t)
I= (1 e L * ;6=15 1 e 15t
R
t = 0.766 s
81.
L=
Nɸ
I
μr μo AN2
=
l
=
500 4πx10-7 10-3 2502
1
1
L= π=0 0393 π
80
Nɸ 250 2x102
I=
=
= 27
1
L
π
80
82. E=
PZɸN
60a
;N=
60aE
PZɸ
=
60x8x400
8x1000 20x10-3
= 2
pm
83. Two wattmeter reading ratio
2 W1
=
1 W2
√3(w1 -w2 )
θ=tan-1 (
w1 w2
84. =1amp turn x
t
85. R= C =
02
05x10-6
√3(2-1)
) =tan-1 (
1 256 gilberts
1 amp turn
1 2
) =30 ;cosθ=pf=
= 2
i
ts
=4
86. A.Series
87. C. Starting
88. Ifault =
Sbase
√3 Vbase Xthpu
AL
=
150 x106
3
√3(13 8 x10 ) 2
=
77 7
89. LF= PL ;AL=LFxPL=(150x103 )( 45)= 67500
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Since annual average load therefore
Hour = 8760
AL= 67500 X 8760 = 591 300 kWhr
90. A. Inclined Break
91. B. 5
92. XC/RM= 100 x 1000 =
93. IL = Ia + Ish
= 50 + 1.2 = 51.2 A
ɳ=
Po
7 8 x 746
x 100%=
x 100= 4 7
Pi
51 2 x120
94. D. LLL
95. C. 1965
96. Zbase =
Vbase 2
Sbase
Zpu =
=
1102
440
= 4 84
Zact
06
=
=
Zbase 9 84
97. Fullwave Amax=
10
707
24
= 4 4
98. VST1 = 100%
VST2 = 50%
T 1 V1 2
=( *
T 2 V2
T1 1 2
=( *
T2 5
T2 = .25T1
T2 = 100 – 25 = 75%
99.
(
(
100.
)
(
C. j0.8241 pu
))
MARCH 2013
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1. A three-phase, 60 Hz wye-connected wound rotor synchronous generator
rated 10 KVA, 230 V has a synchronous reactance of 1.2 ohm per phase and
an armature resistance of 0.5 ohm per phase. Calculate the percent
regulation at full load with 0.8 lagging power factor.
A.18.3%
B.20.8%
C.21.8%
D.22.5%
ZL =
(
√ )
(
= 5 29Ω
EP = (0.5+j1.2)
(230V/√ )
EP= 161.75V
)
ZL
IT=IL=
(
%VR=
√ )
+
x 100%
%VR=21.8%
I T=
2. Farad is equivalent to what unit?
A. Volt-coulomb
B. Coulomb/volt
C. Joule/volt
D. Joule/coulomb
3. A 115 kV three-phase transposed transmission line is composed of 2-ACSR
336,400 cmil, 30/7 Oriole conductors per phase with horizontal configuration:
D12= 7ft, D23= 7ft, and D13= 14ft. The line spacing is measured from the center of
the bundled conductors. The distance between the conductors of the bundle is 6
inches. The conductors have a diameter of 0.741 inch and GMR of 0.02255 ft.
Find the capacitance per phase for 20 km of the line in μF
A.0.1300
B.0.27189
C.0.2889
D.0.2609
4. Three 90 mH inductors are connected in parallel. Find the total inductance.
A.270mH
B.30mH
C.45mH
D.120mH
LT =
= 30mH
5. Which of the following is used in power factor correction?
A. Induction motor
C. Synchronous motor
B. Long transmission line
D. Voltage regulator
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
6. Two equally charged spheres repel each other with a force of 0.1 kg. If their
centers are 20 cm apart, find the change on each.
A. 2.09x10-6coul
B. 2.09x106coul
C. 2.00x10-6coul
D. 2.00x106coul
F = (0.1kg) (9.81) = 0.981N
0.981 =
(
)
(
)
; Q = 2.09x10-6 coul
7. A transformer is rated 1KVA, 220/110V, 60 Hz. Because of an emergency this
transformer has to be used on a 50 Hz system. If the flux density in the
transformer core is to be kept the same as at 60 Hz and 220 V, what is the
kilovolt-ampere rating at 50Hz?
A. 0.871 kVA
B.0.890 kVA
=
C.0.833 kVA
D. 0.909 kVA
; S2 = 0.833KVA
8. The lightning load for a dwelling expressed in terms of a unit load in voltampere
per square meter must be at least ________.
A. 24
B. 12
C. 16
D. 28
9. A hermetic motor compressor has a full-load current of 25A. What is the
allowable rating for branch disconnecting means?
A. 28.75 A
C. 31.25 A.
B. 30 A
D. 37.5 A
10. A metal disk of 30 cm radius rotates at an angular velocity of 1,200 rpm
across a uniform vertical magnetic field of flux density 0.5 Wb/m 2. Calculate the
voltage included between the rim and the center of the disk.
A. 4.4 V
B. 4.7 V
C. 5.1 V
D. 5.8 V
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
V = 0.5(1200)*
Vave =
*
= 62.83 m/s
= 31.42m/s
E = BLV = 0.5 * 0.3 * 31.42 = 4.7V
11. A coil draws 1,875 watts when connected to a 150 V DC source. It consumes 3,072
watts when connected on 240 V, 60 Hz AC source. Find the inductance of the coil.
A.0.0255 H
B.0.0153 H
C.0.0341 H
D.0.0240 H
Solution:
Idc =
R=
= 12.5 A
= 12 Ω
Iac = √
= 15 Ω
Z=
=9Ω
XL = √
= 16 A
L=
(
)
= 0.0240 H
12. What do you call the interior lighting where the roof trusses or ceiling height is
greater than 7.6 m above floor level.
A.HID
B. High Bay
C. High mast
D. High pressure sodium
13. Coil 1 of a pair of coupled coils has a continuous current of 5 A, and the
corresponding fluxes Φ11 and Φ12 are 0.2 and 0.4 mWb, respectively. Find the coupling
coefficient k.
A.0.5
B.0.333
C.0.667
D.0.2
Solution:
Φ1 = 0.2 + 0.4 = 0.6 mWb
K=
=
= 0.667
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
14. Which of the following is a vector quantity?
A. Magnetic Flux
B. Magnetic flux density
C. Magnetic reluctance
D. Magnetic field intensity
15. A certain copper wire has a resistance of 0.5 ohms when the length is 10m. What is
the diameter in mils?
A.57.3
B.33
C.29.4
R=
D.26
0.5 =
L = 10m (
) = 32.8ft
(
)(
A = 680.27cm; d =√
)
= 26mils
= 10 37 Ω 16. An unshaded lamp is placed at a distance r1 above the ground and produces an
illumination E1 at a point on the ground directly below the lamp. At what angle must the
lamp be aimed on the ground to produce an illumination one-half of E1?
A.45 degrees
B.37.5 degrees
C.30 degrees
D.27.5 degrees
17. Two equal resistors wen connected in series across a supply draws a total of 20
watts. What is the total power drawn when two resistors are connected in parallel
across the same supply?
A.20 W
B.40 W
C.60 W
D.80
Pp = n2 Ps ; n = 2 ; Ps = 20 watts ;
Pp = (2)2 (20) = 80W
18. The Electrical Safety Month of the year is ______?
A. June
B. April
C. February
D. May
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
19. The area of one plate of a two plate mica capacitor is 0.0025 m 2 and the separation
between plates is 0.02 m. If the dielectric constant of mica is 5, what is the capacitance
of the capacitor?
A.5.53 μF
C 7 74 μF
B.5.53 pF
C=
C=
= 8.85 pF/m
(
)( )(
)
D.7.74 pF
(2-1)
C = 5.53pF
20. Which of the following produces a reactive power?
A. Incandescent lamp
C. Flat iron
B. Induction motor
D. Heater
21.
What capacitance must be placed in series with an inductance of 0.05 H so that
at 100 Hz, the impedance becomes equal to the ohmic resistance?
7μF
B 70 7μF
C 35 5μF
D 87μF
Solution:
Using the formula:
√
Then derive it to form the equation: 𝐶 =
22.
(
)(
)(
)
=
7μF
Receptacle outlets shall be located above, but not more than______ mm above
the countertop.
A.300
B.450
C.250
D.600
23.
In dwelling units, hallways of __ m or more in length shall have at least one
receptacle outlet.
A. 4
B. 2
C. 5
D. 3
24.
A 16-ohm resistor is connected in series with parallel combination of three
resistors, R and 48 ohms. Determine R if the power consumed by the parallel
connected resistor is equal to the power consumed by the 16-ohm resistor.
A. 6 ohms
B. 12 ohms
C. 24 ohms
D. 36 ohms
Solution:
Using the formula: P = I2R
Since: P48R = P16
(
I2 (
)( )
)
=
(
R = 24 Ohms
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
25.
26.
The time constant of a series RL circuit Is equal to _____?
A. L/R
B.R/L
C. RL
A commercial building with an aggregate three-phase load of 170 kVA is to be
served using two single-phase transformers connected in V-V bank. What should
be the minimum size of each transformer in kVA.
A.167
B.75
C.100
√
27.
= 100KVA
B.240 V
V2 =
29.
C.200 V
D.100 V
= 288V
Heating effect of current has undesirable side effect in
A. Electric oven
C. Electric iron
B. Immersion heater
D. Vacuum cleaner
In an electric system the available short-circuit MVA is 600 MVA. What is the
Thevenin’s equivalent reactance at 34 5 kV?
A.1.14 ohms B.2.29 ohms
X=
30.
D.333
A 240 V to 120 V, 50 Hz step-down transformer is to be operated at 60 Hz. What
is the highest safe input voltage?
A.288 V
28.
D. 1/RL
(
C.1.98 ohms
)
D.1.32 ohms
= 1.98 ohms
The net cross section of a transformer is 29 square inches. The maximum flux
density is 11 kilogausses. The frequency is 60 Hz. If there are 1,000 turns in the
primary, determine the primary induced emf.
A.3,780 V
B.3,590 V
C.3,850 V
D.3,945 V
E = (4.44 * 1000 * 60 *11x10-3 * (20(2.54)2)) x10-8
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
E = 3,780V
31.
A 15MW, 132 kV, 80%power factor three phase load is to be served by a
transmission line having conductors whose resistance is 0.5 ohm/km. If the
losses on the line shall not exceed 4.5%, how long must this line be?
A. 66 km
(
32.
B. 68 km
)
(
35.
; x= 70 km
B. 5%
C. 25%
D. 20%
In a 3-phase, 4 wire system, the current in line a has I a1=2200 deg A and
Ia2=10060 deg A. the current through the neutral conductor is 300-60 deg.
Find the line current Ib in amperes.
A. 100-300
34.
D. 75 km
A change of 5% in the supply voltage of a three-phase induction motor will
produce to its torque a change of approximately _______.
A. 10%
33.
)
C. 70 km
B. 100120
C. 100-60
D. 300240
In two-wattmeter method, the readings of the wattmeter will be identical when
A. Load in one of the phases is zero
C. Power factor is 0.5
B. Power Factor in unity
D. Neutral is earthed
A capacitor of 100 micro farad is connected in series with a resistance of 1000
ohms. The time constant of the circuit is
A. 1 sec
B. 0.01 sec
C.0.1 sec
D. 0.001 sec
T= 1000*100x10-6= 0.1s
36.
An electric current can neither be ______nor______.
A. Felt, seen
C. Seen, touch any effect
B. Seen, touched
D. Produced, felt
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
37.
38.
A three-phase 4-pole 50 Hz induction motor has a rotor resistance of 0.020 ohm
per phase and standstill reactance of 0.5 ohm per phase. Calculate the speed at
which the maximum torque is developed.
A.1,500 rpm
C. 1,480 rpm
B.1,460 rpm
D. 1,440 rpm
Two capacitors A and B have capacitances of 50F and 30F, respectively.
When 230V, 50 Hz voltage is applied, find the maximum energy stored assuming
A and B are connected in series.
A. 0.992 J
B. 4.232
cT=
C. 1,984 J
D. 2.116 J
= 18.75F
w = (230)2(18.75x10-6)= 0.92
39.
Find the average power in a resistance R=10 ohms, if the current in the Fourier
series form is i=12 sin ὠt + 8 sin ὠt + 3 sin 5 ὠt amperes.
A. 1, 150 W
B. 1,027 W
C. 1,085
D. 1,203
Irms = √ ( 122+82+32 ) = 10.42A
P= 10.422* 10 = 1085 W
40.
41.
In transmission voltage levels, 765kV is categorized as
A. High Voltage
C. Ultra High Voltage
B. Extra High Voltage
D. Medium Voltage
Two parallel long conductors will carry 100 A. If the conductors are separated by
200 m, the force per meter length of each conductor will be_____.
A.10 N
B.0.1 N
C.1 N
Solution:
F = (2x10-7) (100)2 (100) = 0.2/2 = 0.1N
D.100 N
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
42.
To a series RLC circuit, a voltage of 10 V is applied. If Q of the coil at resonant
frequency is 20, the voltage across the inductor will be _____.
A.2 V
B.50 V
C.100 V
D.200 V
Solution:
20 =
43.
; VL = 200V
For a coil having a span of 2/3 of pole pitch, the coil span factor is
A.0.8
B.0.866
C.0.786
D.0.966
Solution:
Kp = sin (90 * ) = 0.866
44.
The potential transformer of the line has a rate of 132,000/66. These are
connected wye-delta. The voltmeter reads 64 V. What is the average of the line?
A.221.7 kV
B.112.5 kV
C.135.2 kV
D.132 kV
Solution:
Vp = 64 (
45.
) = 128KV * √ = 221.7KV
A 50 Hp, 440 V, 3-phase, 60 Hz,6-pole squirrel cage induction motor is operating
at full load and 0.8 p.f. The full load efficiency is 85% and the percentage slip is 5
%. Determine the full load torque.
A.214.55 N-m
B.206.72 N-m
C. 312.47 N-m
D.323.24 N-m
Solution:
0.85 =
T=
46.
(
)
= 292 16
= 34875.5W
312.47
The purposes of a grid system is to
A. Interconnect the power stations
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
B. Supply energy to remote areas
C. Make extra high voltage available to consumers
D. Make distribution of energy at reasonable cost
47.
The efficiency of thermal plant is approximately
A.10%
48.
B.30%
C.60%
D.80%
What is the half power bandwidth of a parallel resonant circuit which has a
resonant frequency of 3.6 MHz and Q of 218?
A.1.65 kHz
B.16.5 MHz
C.16.5 kHz
D.165 kHz
Solution:
BW =
49.
The number of parallel paths in a simplex lap winding is equal to
A. 2
B. Number of poles
50.
= 16.51kHZ
C. Number of pair of poles
D.1
The power consumed by a heating element made of copper wire is 250 W at 220
V and 30 degrees Celsius. What is the power consumed by the same element at
220 V and 100 degrees Celsius? The temperature coefficient of the element at
30 degrees Celsius is 0.004-degree C-1.
A.274 W
B.233.33 W
Solution:
R1 =
= 193.6 ohms
0.004 =
T = 200 degrees Celcius
R2 = 193.6 *
= 274.81 ohms
C.215.25 W
D.196.31 W
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
51.
A generator rated 600 kVA, 2,400 V, 60 Hz, 3-phase, 6-poles and wye-connected
has 10% synchronous reactance. If a three-phase fault occurs at its terminals,
what will be the short-circuit current?
A. 1,428 A
52.
B. 1,443 A
Given:
S= 600kVA V= 2400V
Formula:
Three Phase Fault Formula, If =
Solution:
If =
√ (
)(
)
f= 60Hz
D. 1,435 A
P= 6-poles
Z1pu= 0.10
√
= 1443.38 A
A 200-Hp 2,200 V, 3-phase star connected synchronous motor has a
synchronous Impedance of 0 3 j3 Ω per phase Determine the induced emf per
phase if the motor works on full-load with and efficiency of 94% and a power
factor of 0.8 leading.
A. 1,354 V
Given:
B. 1,360 V
C. 1,402 V
Po= 200Hp x 746W/1Hp
= 149200W
Pi= (149200) (0.94)
= 140248W
Formula:
I=
Solution:
I=
Vp =
√
√ (
Vp =
53.
C. 1,532 A
√
)(
)
Z= 0 3
j3 Ω per phase
p.f. = 0.8 leading
√
=
(
Vline = 2200V
D. 1,522 V
A
)(
)=
If the load of a wye-connected transformer are:
Ia = 10 cis (-30o)
Ib = 12 cis 215o
Ic = 15 cis 82o
What is the phase b sequence component?
A.13.4 cis (-32.2o)
B. 10.2 cis 240o
Given:
Ia = 10 cis (-30o)
C. 12.27 cis 208.4o
D. 12.27 cis (-31.6o)
Ib = 12 cis 215o
Ic = 15 cis 82o
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Formula:
Ia1 = (
)
Ib1 = (
Solution:
Ia1 = (
55.
)(
)
(
)(
)
)(
)
(
)(
)
)Ia1
)
Ia1 =
Ib1 =(
54.
(
(
) (12.27
)= (
)
If the input of the prime mover of an alternator is kept constant but the excitation
is increased then
A. kVA will be leading
C. kW will be changed
B. kVA will be lagging
D. the power factor of the load remains constant
A current of 10 A is flowing in a flexible conductor of length 1.5 m. A force of 15 N
acts on it when it is placed in a uniform field of 2 T. Calculate the angle between
the magnetic field and the direction of the current.
A. 30o
Given:
Formula:
Solution:
B. 45o
C. 60o
F = 15 N
β=2T
F=
15 = (2) (10) (1.5) sin
= sin-1(
I = 10A
D. 90o
L = 1.5m
)
O
56.
The useful life of diesel engine in a power plant is expected to be ______ year/s.
A. 5
57.
B. 1
D. 15
An automatic device that operates at preset values is known as
A. Mercury switch
B. fuse
58.
C. 50
C. relay
D. contactor
A 240 V dc series motor develops a shaft torque of 200 N-m at 92% efficiency
while running at 600 rpm. Calculate the motor current.
A. 62.09 A
B. 52.36 A
C. 48.17 A
D. 56.91
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Given:
V = 240 V
Formula:
HP =
Solution:
HP =
T = 200 N-m
n% = .92
n% = Po/Pi
(
(
)(
N = 600 rpm
Ia = Po/V
)
)
= 13659.1 W
= 56.91 A
59.
A magnetic field copper exists around
A. Copper
60.
C. Moving charges
D. Aluminum
A voltage of e = 7.07 sin 50t v is applied to a series circuit containing a resistance
of 4 ohms and an inductance of 60 mH. What is the impedance of the circuit in
ohms?
A. 5
Given:
Formula:
Solution:
61.
B. Iron
30o Ω B. 5
60o Ω
C. 5
53.13o Ω
e = 7.07 sin 50t
Ѡ = 50 rad/sec
XL = ѠL
Z = R + j XL
XL = (50) (60x10-3 = 3 Ω
Z=4+j3Ω =
D. 5
36.87o
R=4Ω
A 230 V, 3-phase, 3-wire system has to balanced 3-phase loads. One, wye
connected has impedance of 6 j8 Ω per phase and the other one, delta
connected has impedance of 24
j18 Ω per phase Find the line current in
amperes.
A. 26.3
B. 23.9
Given
V= 230v
Z =24+j18
Solution
(3)Z =Z
Z
=
C. 28.2
Zy=6+j8
= 8 + j6
Z = Z // Z
Z
(
(
)(
) (
)
)
=
D. 20.8
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
`
62.
(
IL = I =
) √
=
It is desired to deliver 4,000 kW, three-phase at a distance of 25 miles. The load
voltage being 33 kV, 60 Hz and the power factor of the load being 85% lagging.
The reactance of the line per phase is 0.692 ohm per mile. The line loss is 10%
of the power delivered. What is the voltage regulation of the line?
A. 11.2%
B. 12.3%
Given
P= 4,000kW
f= 60Hz
Solution
Ir=
C. 13.2%
D. 14.8%
V= 33kV
pf=0.8
√
IR =
√ (
)(
)
PLoss = 400, 000 W
R=(
)(
)
%VR =
= 19.67 Ω
)
% VR = 11.2%
VS = VR + IZ
VS = 21182.4
63.
The voltage applied to the stator of a three-phase, 4-pole induction motor has a
frequency of 50 Hz. The frequency of the emf induced in the rotor is 1.5 Hz.
Determine the speed at which motor is running.
A. 1,410 rpm B. 1,425 rpm
Given
f=50Hz
p=4
Solution
C. 1,448 rpm
D. 1,455 rpm
N=
(
Ns =
Fr =
1.5 =
64.
(
)
= 1500 rpm
)
(
)
Nr = 1455 rpm
The applied voltage is increased by 50% and frequency is reduced by 50%. The
maximum core flux density will become
A. 1.5 times B. 3 times
C. 5 times
D. the same
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
65.
Surge impedance of transmission line is given by
66.
A √C/L
B √CL
√L/
D 1/√LC
Which of the following is not a type of the contactor for circuit breakers?
67.
A. Vacuum
C. Electro-pneumatic
B. Pneumatic
D. Electromagnetic
A three-phase motor driven pump at 1,800 rpm is discharging 500 gpm of water
at a head of 25 meters. The pump efficiency is 75%. Determine the horsepower
of the motor.
A. 15
Given
B. 12
C. 14
N=1,800rpm
efficiency=75%
D. 10
L=25m
Solution
Pin =
(
)(
Pin =
68.
)(
)
=
= 14Hp
The average weekly energy generated by a thermal plant is 7 x 10 6 kWHR. The
peak load of the plant is 75,000 kW during the week. If the plant has an installed
capacity of 100 MW, solve for the load factor of the plant.
A. 48.92% B. 56.34%
Given
W=7x10
kWh
P=100 MW
Solution
C. 50.44%
D. 55.55%
P=75,000kW
Lf =
Lf = (
69.
)(
)
A 15 MVA, 34.5 kV / 6.24 kV transformer is connected at an infinite bus. The
percent impedance of the transformer is 2.5%. What is the current at the 34.5 kV
side for a three-phase fault at the 6.24 kV side?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 25,000 A
C. 55,500 A
Given
S=15MVA
Zpu=0.025
Solution
, If =
If =
70.
71.
B. 5,000 A
D. 10,000 A
V= 34.5kV/6.24kV
√
√ (
)(
)
=
Charging a lead-acid cell causes the electrolyte to become
A. stronger B. stable
C. weaker
D. water
A coil has a resistance of 5 ohms and inductance of 1 H. At t = 0 it is connected
to a 2 V battery. Find the rate of rise of current when i = 0.2 ampere.
A. 3 A/sec
B. 2 A/sec
C. 1 A/sec
Given: R = 5 ohms
L=1H
t=0
i = 0.2 A
D. 0.5 A/sec
Required:
Solutions:
V = iR + L
2 = (5) (0.2) + 1
72.
A shunt motor has a rated armature current of 50 A when connected to 200 V.
The rated speed is 1,000 rpm and armature resistance is 0 1 Ω Find the speed if
the total torque is reduced to 70% of that at rated load and a 3 Ω resistance is
inserted in series with the armature.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 474 rpm
B. 469 rpm
C. 464 rpm
D. 460 rpm
Given: Ia1 = 50A
E1 = 200V
T1
T2 = 0.7T1
N1 = 1000 rpm
Required: N2
Solutions:
)2
(
)2
(
Ia2 = 27.32A
(
(
73.
)
= 469 RPM
If the resistance of the field winding of a dc generator is increased the output
voltage will
A. decrease
B. increase
74.
)
)(
C. remain the same
D. fluctuate heavily
Wye-wye power transformers are protected by current transformers having
________ connection.
A. delta-delta
B. wye-delta
C. delta-wye
D. wye-wye
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
75.
An unbalanced wye-connected load connected to a 3-phase, 4-wire abc system
consists of Za = 10 j5 Ω, Zb = 8 j4 Ω and Zc = 20 + j0 Ω If the line to neutral
voltage is 120 V, find the total power in watts.
A. 4,125
B. 3,312
C. 5,520
D. 2,843
Given: Za = 10 j5 Ω
Zb = 8 j4 Ω
Zc = 20 j0 Ω
VT = 120 V
Required: PT
Solutions:
ST =
ST =
+
+
+
+
ST = 3312 – j1296
PT = 3312W
76.
A three-phase, 60 Hz, transmission line has its conductors arranged in a
triangular configuration so that the two distances between conductors are 7.62 m
and the third is 12.8 m. The conductors are Dove with GMR of 0.0314 ft. If the
line is 60km long, what is the inductive reactance of the line?
A 38 73 Ω
B 37 18 Ω
Ω
D 33 57 Ω
Given: F = 60Hz
d1 = d2 =7.62 m
d3 =12.8 m
GMR = Ds = 0.0314 ft
L = 60 KM
Required: XL
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Solutions:
Dm = √(
77.
78.
)
L = 2x10-7 ln(
)
XL = 2 (
)
)(
D.foot-candle
The barrier potential for a silicon diode at 25 oC is approximately
B. 0.3 v
C. 0.7 v
D. 0.5 v
C. 10 Gb/cm
D. 100 Gb/cm
Ten oersted is equivalent to
A. 10 Gb/m B. 1 Gb/m
80.
)(
The luminous intensity of a lamp is expressed in
A. lux
B. lumens
C. candela
A. 0.4 v
79.
)(
In a 230 V, 3-phase, 3-wire system, two wattmeters are connected to measure
the power. The ratio of the readings of the wattmeters is 2.5 is to 1. What is the
power factor of the system?
A. 80.3%
B. 76.6%
C. 83.1%
D. 86.6%
Given: ratio =
Required: Pf
Solutions:
Φ = tan-1 (
√ (
)
)
Pf = cos (36.59) = 80.3%
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
81.
An impedance draws a current i = 10 cos ωt – 30o) from a voltage v = 220 sin
ωt What is the maximum power?
A. 1,100 W B. 2,200 W
Solution:
Vrms =
√
C. 1,320 W
D. 190.5 W
xV
Vrms = (220) (0.707) = 155.54 V
Irms = i x
√
= 7.07 A
Irms = (10) (0.707) = 7.07 A
P = Irms x Vrms
P = (7.07 A) (155.54 V)
P = 1100W
82.
Calculate the magnetic field intensity to produce a flux density of 10 x 10 -3 tesla
at the center of a long straight solenoid.
A. 6,423 AT/m B. 7, 958 AT/m C. 8,323 AT/m D.7,869AT/m
Solution:
H=
= Free space permeability
=
(SI units)
=1 (cgs units)
H=
H= 7958 AT/m
83.
A total of 0.8 kg of water at 20 oC is placed in a 1-kW electric kettle. How long a
time in minute is needed to raise the temperature of the water to 100 oC?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 4.46 min
Solution:
B. 4.56 min
C. 5.32 min
D. 6.34 min
Q = mC
Q=(0.89)(4186J/kg-c)(100-20)c
Q = 267904J = W
W = Pt; t =
t=
(
t=
)
t= 4.46 min
84.
A certain amount of fuel can produce 10 quads of energy. In how many days will
the fuel be totally consumed if it is used to satisfy a demand of 10 13 BTU/day at a
power plant with and overall efficiency of 20 percent?
A. 190
85.
B. 205
C. 195
What is the equivalent of the constant C in the ABCD constants for the NominalT
circuit of a transmission line for which R = 10 Ω, XL = 20 Ω, Y = 400 µs for
each phase?
A. 0.996 0.115o
B. 22.25 63.45o
C. 10 + j20
D. 4 x 10-4 90o
C = 0 +jY
= 0 + j 400x10-6
C = 400x10-4 90
86.
D. 200
Which of the following ammeters is the most sensitive?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 0-100 micro ammeter
B. 0-5 milli ammeter
C. 0-1 micro ammeter
D. 0-50 milli ammeter
Note: The smaller the amount of current, the more “sensitive” the
ammeter.
87.
A transformer is to be used to match a secondary load impedance of 800 ohms
to a generator line impedance of 128 ohms. What should be the ratio of
transformation of the transformer for maximum power transfer?
A. 1: 6.25
B. 6.25: 1
C. 1: 2.5
D. 2.5: 1
Pmax = √
88.
TV Channel 2 has a frequency of 60 MHz What is the wavelength?
A. 50m
B. 500m
C. 0.5m
D. 5m
Solution:
Wavelength ( ) =
Wavelength ( ) =
Wavelength ( ) = 5m
89.
At a certain point of the system network the positive, negative and zero sequence
impedances are 0.25 p.u., 0.25 p.u. and 0.3 p.u., respectively. The base MVA is
100. The voltage level at that point is 34.5 kV. Determine the zero sequence
current for a one-line ground fault.
A. 8.132 A
B. 7,516 A
C. 6,275 A
Solution:
=
=
=
=
= 1.25pu
D. 2,091 A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
=
√
=
√ (
=
= 1673.48
)
(
)
= 1.25 (1673.48)
= 2091.81
90.
A 1-phase, 220-V 50-A induction motor draws 10 kW of power. A 1-phase, 8-kVA
synchronous motor is placed parallel with it in order to adjust the power factor to
unity. What must be the power factor of the synchronous motor?
A. 0.80 leading
C. 0.84 leading
B. 0.82 leading
D.0.86 leading
Solution :
)
Qc = P (tan
= 1000 (tan (24.92) – tan (0))
Qc = 4582.58 VAR
= sin-1 (
= sin-1 (
91.
92.
)
)
Pf = cos (34.92) = 0.82 leading
Brushes of dc machine are usually made of
A. carbon
B. hard copper
C. soft copper
D. iron
Impurities in an electrolyte can cause an internal short circuit condition called
A. Depolarization
B. Electrolysis
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
93.
94.
C. Local action
D. Polarization
Calculate the time taken by the capacitor of 1 µF and in series with a 1 MΩ
resistance to be charged up to 80% of the final value.
A. 0.8 sec
B. 1.61 sec C. 2,12 sec
D. 1.98 sec
Determine the inductance L of a coil of 500 turns wound on an air cored torroidal
ring having a mean diameter of 300mm. The ring has a circular cross section of
diameter 50mm.
A. 6.54 x 10-3 H
B. 6.54 x 10-4 H
C. 3.27 x 10-3 H
D. 3.27 x 10-3 H
Solution:
N = 500
= 1.963x10-3m2
d = 300x10-3 m
L
=
=
C=
= (300x10-3)
(
)(
)(
)
= 0.942m
D = 50mm
L
=
6.54x10-4
H
A=
95.
96.
97.
=
(
)
What is the minimum number of wattmeter required to measure unbalanced
power for a three phase system?
A. 2
B. 3
C. 4
D. 1
The rotor of a 220 v, 60 Hz, 4-pole induction motor has a power input of 80 kW. It
is observed that the rotor emf makes 90 cycles per minute, Calculate the rotor
copper loss.
A. 2 kW
B. 5 kW
C. 3 kW
D. 4 Kw
Solution:
V = 220V
S=
=
= 0.025
f = 60hz
Pcu = SPr
P=4
= (0.025)(80kW)
Pin = 80kw = Pr
Pcu
=
2kW
Sf = 90 cpm
= 90/60 cps= 1.5 = fr
A certain station in Luzon has 36 kV, 3-phase, is to supply 12 MW load at 30 kV
and 0.8 p.f. lagging over a 3-phase transmission line. Find the resistance of the
line if the length of the transmission line is 4,000 meters and the efficiency is
90%.
A 6 31 Ω
B 3 56 Ω
C 4 45 Ω
D
Ω
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Solution:
V = 36kV
PL = 12MW
VL = 30kV
Pf = 0.8 Lagging
Ƞ = 90%
PL = √ ILVLpf
IL
Ƞ=
0.9
Pline = 1.33kW
R=
R
=
√ (
=
)(
=
5.33
)
IL=288.68A
98.
A dc shunt generator has an induced voltage of 220 v on open circuit. When the
machine is on load the voltage is 200 v. Find the load current of the filed
resistance is 100 Ω and armature resistance is 0 2 Ω
A. 100 A
B. 102 A
C. 98 A
D. 96 A
Solution:
Eg = 220V
VL = 200V
RSH = 100
Ra = 0 2
ISH =
=
= 2A
Eg = VL+IaRa
220 = 200 + Ia(0.2)
Ia = 100A
Ia = IL + Ish
Ish = 100 – 2
Ish
=
98A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
99.
100.
Permeance is analogous to
A. Conductance
B. Resistance
C. Reluctance
D. Inductance
A 100 MW power station delivers 100 MW for 2 hours, 50 MW for 8 hours and is
shut down for the rest of each day. It is also shut down for maintenance for 60
days each year. Calculate its annual load factor.
A. 19%
B. 21%
C. 23%
D. 25%
AUGUST 2013
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1. Two Impedances C1 and C2 are connected in series across a 240 v source. If
C1 is 24µF and the total capacitance is 6µF, find the voltage across C 2.
A. 240v
B. 60v
C. 180v
D. 120 v
Solution:
XCT=
=
(
)(
)
=442 0970641 Ω Xc1=
(
)(
)
= 110 524 Ω
= 0.5429 v
I1=VT/XCT=
V1= (I1)(X1)=(0.5429)(110.524)= 60 v
V2= VT – V1=240-60
V2= 180 v
2. Estimate the average power output of a wind turbine having a blade diameter
of 10.7 m if the wind velocity ranges from 10 to 30 miles per hour.
A. 40.2kW
B. 42.2kW
C. 44.2kW
D. 46.2kW
Given:
Solution:
d= (10.7)(3.2808)=54.1ft
P=2.46x10-3(d2)(v3)
v= 10.30 mph
P10= 2.46x10-3(35.12)(103) = 3030.7
P30= 2.46x10-3(35.12)(303) = 81830.1
Po=42.2kW
3. A conductor radius of 0.1625 inch. What is the area in circular mils?
A. 26,406.25
B.82,957.68
C.100,000
D. 105,625
Given:
r=0.1625in
D= 162.5 mils
= 162.5 mils
2 = 325 mils
A= D2 = 3252
A=105,625 CM
4. If there are eleven resistors of 33kΩ each in parallel, what is the total
resistance?
A. 363kΩ
B 3 3kΩ
Ω
D 16 5kΩ
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
RT=
(
)(
)
=
Ω
5. To reverse the direction of rotation of a three-phase induction motor, it is
necessary to
A. Interchange all the three line connections
B. Reverse the polarity of the rotor circuit
C. Increase the resistance of the rotor circuit
D. Interchange any two of the three line connections
6. An unconventional conductor consists of three strands arranged vertically.
Find the GMR in terms of the radius r of an individual strand.
A. 1.564 r
B.1.764 r
C. 1.704 r
D. 1.89 r
7. Transformers are rated in
A. KW
B. KV
C. KWHR
D. KVA
8. A current is given by the expression i=2.5
+ 0.8
+ 0.5
.
What is the rms value of the current?
A. 1.54 A
B.2.6 A
C.2.54 A
D. 1.89 A
Given:
i= 2.5
+ 0.8
+ 0.5
Solution:
IRMS= √
=√
(
)
(
)
(
)
IRMS=1.89 A
9. A capacitor is charged to 250 coulombs for 5 seconds. What is the current
through the capacitor.
A. 25 A
B. 50 A
C. 500 A
D. 1,250 A
Given:
Solution:
Q=250 C
Q=It
T= 5sec
I=
I= ?
I=50 A
10. In a series RL circuit, the inductor current _________ the resistor current.
A. Lags
B. leads
C. is equal to
D. is negative of
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
11 A 120v dc shunt motor has an armature resistance of 200 mΩ If the full-load
armature current is 75 A, find the starting resistance needed to limit the armature
starting current to 150% of the full-load value.
A 0 804 Ω
B 0 822 Ω
4 Ω
D 0 862 Ω
Solution:
Vt=Eb + Ia(Ra+Rst) + Vbc
Eb=0 at starting
Rst=[(Vt-Vbc)/(1.5(Ia))] - Ra
Rst=[(120-2)/(1.5(75))] - 200×10^-3
Rst=0.849 ohm
12. The power factor of incandescent bulb is
A. 0.8 lagging
B. 0.8 leading
C. unity
D. zero
13. The law that induces emf and current always opposes the cause producing
them was discovered by
A. Lenz
B. Maxwell
C. Faraday
D. Ohm
14. An inductor in series with a 5 µF capacitor is connected to supply of 20 v,796
HZ. What is the inductance needed to make the current 5 A leading?
A. 0.002 H
GIVEN:
C = 5µF
V = 20 v
f= 796HZ
I=5
B. 0.007 H
C. 0.004 H
D. 0.008 H
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
L=?
Solution"
Xc =1/ 2πfc = 1/ 2π 796 5x10-6)
Xc = 39 99 Ω
Z = V/I = 20/5 =4
Z= Xl - Xc
XL = 2π f L
4 = XL - 39 99
3599 = 2π 796 L
XL = 35.99
L = 0.007 mH
15. A 60 kJ per minute heat is rejected from refrigerator. What is the power input
to the refrigerator if cop is 1.2?
A. 0.633 kw
B. 0.733 kw
C.0.833kw
D. 0.933 kw
Solution:
COD = pi/ pr
60 kj/min x 1min/x = 1 kj/s = 1000w
1.2 = 1000/x
X = 0.833 kw
16. A 2.400/240 volts transformer is connected Y-∆ What is the base voltage of
the secondary?
A. 415.69 v
B. 240 v
C. 135.56 v
D. 480 v
2,400/240
PRIMARY =2,400
SECONDARY =240
17. Temperature coefficient of a conductor is defined as the
A. increase in resistance per ohm per degree centigrade
B. increase in resistance per degree centigrade
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
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PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
C. increase in resistance per degree absolute
D. decrease in resistance per ohm per degree centigrade
18. A 400 v series motor working with unsaturated field is taking 60 A and
running at 840 rpm. The total resistance of the motor is 0.1 ohm. At what speed
will the motor run when developing half-full load torque.
A. 1,193 rpm B. 1,202 rpm
C. 1,167 rpm
D. 1,352 rpm
Solution:
(T2/T1) = (Ia2/Ia1)^2
(0.5T1/T1) = (Ia2/60)^2
Ia2 = 30 sq. rt of 2
Eb1 = Vt-Ia1(Ra)
=400-60(0.1)
Eb1 = 394v
Eb2 = Vt-Ia2(Ra)
=400-30 sq.rt of 2(0.1)
Eb2 = 395.757
(Eb1/Eb2) = [(N1(Ia1))/(N2(Ia2))]
N2 = [Eb2(N1)(Ia1)]/[Eb1(Ia2)]
= [395.757(840)(60)]/[394(30 sq.rt of 2)]
N2 = 1193 rpm
19. A capacitor is placed in parallel with two inductive loads, one of 20 A at 30°
lagging and another one of 40 A at 60° lagging. What must be the current in the
capacitor so that the total current from the source shall be at unity power factor?
A. 44.64 A
Solution:
B. 36.84 A
C. 48.36 A
D. 38.32 A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
I = (20<30)+(40<60)
= 37.32 + 44.64i
Therefore, the current in the capacitor is 44.64A
20. Open conductors run individually as service drops shall be _______.
I. insulted
A. I only
II. bare
B. II only
III. covered
C. III only
D. either I or II
21. A three-phase short transmission line has a per phase impedance of 0.3 +
j0 4 Ω The receiving end voltage is 6 351 volts per phase and the voltage
regulations is not exceed 5 percent. Calculate the total line loss when it is
supplying maximum power.
A. 212.08 MW
B. 7.69 MW
C. 122.46 MW
D. 40.81 MW
22. A parallel plate capacitor is made of 350 plates, separated by paraffined
paper 0.001cm thick (k=2.5). The effective size of the plate is 50 cm x 30 cm.
What is the capacitance of this capacitor?
A. 35 µF
B. 70 µF
C. 115 µF
D.140 µF
GIVEN:
n = 350
k = 2.5 =
d=0.001 cm
Σr= 50x10-2x30x10-2)
Solution:
C = ΣoΣr / d n-1)
C=(8.8SAx1018)(2.5)(50x10-2x30x10-2)/0.001x10-2(350-1)
C = 115 µF
23. The percentage overloading of two 20 - KVA transformers when supplying a
balanced 3 ᶲ load of 10 kVA in a V-V bank is ______ percent.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
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PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 15 B. 57.7
C. 73.2
D. 33.3
24. The power factor of an alternator is determined by its
A. speed
B. load
C. excitation
D. prime mover
25. The pitch factor for 3rd harmonic in an alternator having 18 slots per pole and
coil span 5/6 of pole pitch is
A. 0.707
B. 0.253
C. 0.966
D. 1
Solution:
K3=cos 3α/2
K3=cos(3(30)/2)
α=180O 1-5/6)=30O
=0.707
26. A certain power plant has reserve capacity above the peak load of MW. The
annual factors are load factor = 59%, capacity factor = 41% and use factor 46%.
Determine hours per year not in service.
A. 952 hours
B. 965 hours
C. 924 hours
D. 937 hours
LF = L/ PL
∆L = LE (PL)
= 0.59 (PL) -1
INSTALLED CAPACITY = PL + RESERVED
PL = 1.C -10 -2
SUBSTITUTE EQ. 2 IN EQ. 1
∆l =0.59 (INSTALLED CAPACITY -10)
=0.59 INSTALLED CAPACITY -59- 3
PCF = ∆L / INSTALLED CAPACITY
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
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PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
∆L =0.41 (INSTALLED CAPACITY) -4
EQUATE 3 TO 4
∆L = 0.59 (32.78) -5.9
= 13.44 MW
PUF YEAR = ∆L IN MW - HR / INSTALLED
CAPACITY IN MW x N
0.46 = 13.44 x 8768 /32. 78 N
N= 7808 HRS
LET n = 8760 -7808
= 952 HRS
27. The speed of a synchronous motor
A. reduces as load increases
B. increases as load increases
C. adjusts itself to new equilibrium speed whenever load changes
D. always remains constant
28. A heater wire of length 50 cm and 1 mm2 in cross-section carries a current of
2 A when connected across a 2 v battery. What is the resistivity of the wire?
A. 2 x 10- Ω-m
B. 2 x 10-5 Ω-m
C. 4 x 10-6 Ω-m
D. 4 x 10-5 Ω-m
GIVEN:
Find:
L = 50 x 10 -2 m
I = 2A
d = 1x10-3 m2
V=2v
Solution:
R = V/ I = 2/2 = 1Ω
R = PL/A
P=?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
P=RA/L
P= 1Ω 1x10-3m2)/(50 x 10-2m) =2 x 10- Ω-m
29. A string insulator has 4 units. The voltage across the bottom most unit is 30%
of the total voltage. What is the string efficiency?
A. 30%
B. 60%
C. 75%
D. 83.33%
Given:
Solution:
Where: n=4 (number of disc)
%SE=Vph/n x VDNC
Vph=operating phase voltage
%SE=Vph/4 x Vph x 0.30
Voltage disc nearest to conductor=VDNC
=Vph x 0.30
%SE=(1/4 x 0.30)100
= 83.33%
30. When a line to ground faults occurs, the current in a faulted phase is 100 A.
What is the zero sequence current in this case?
A. zero
B. 33.3 A
C. 66.6 A
D. 100 A
31. A transmission line has a total series impedance of 40 + j125 ohms and a
total shunt admittance of 10-3 mho. Determine the constant D of the line.
A. j0.001
B. 0.9376 + j0.0196
C. 1 + j0.0656
D. 0.001 + j0.0656
32. A six-pole three-phase 440-v, 60 HZ induction motor develops 10-HP at
1,150 rpm, the power factor being 80% lagging. Stator and core losses amount to
400 w and 350 w, respectively. Frictional losses amount to 0.5-hp. Calculate
motor line current.
A. 12.24 A
B. 12.41 A
C. 11.42 A
D. 14.64 A
33. The efficiency of thermal power plant is approximately
A. 10%
B. 30%
C. 60%
D. 80%
34. A 6.6 kV Y-connected, 3-phase alternator has a synchronous reactance of 6
Ω per phase and a negligible resistance At a certain field current, the armature is
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
known to induce 5.8 kV per phase. Calculate the maximum power that can be
developed by the alternator at this excitation.
A. 12 MW
B. 10 MW
Given:
C. 9.8 MW
D. 11 MW
Find: Max power
V line = 6600 / √3
Z= 0+j6
X= 6 ohms
Va= 5800
R= 0
Solution:
I= V / Z
Pmax = 3 VI
I= 6600 /√3 / 0 j6
Pmax = 3 (5800) (635.09) `
I= -j635.09 = 635.09A
Pmax = 11050566W or 11.05MW
35. A power plant consumes 3,600 tons of coal per day. If the coal has an
average energy content of 10,000 BTU/lb, what is the plant's power output?
Assume an overall efficiency of 15%.
A. 132 MW
B. 130 MW
C. 128 MW
D. 126 MW
36. The positive, negative, and zero sequence reactances of a 20-MVA, 1302 kV
synchronous generator are 0.3 pu, 0.2 pu, nad 0.1 pu, respectively. The
generator is solidly grounded and is not loaded. A line to ground fault occurs on
phase a. Neglecting all the resistances, determine Ia1.
A. -j5 pu
B. -j1.67 pu
C. -j2.87 pu D. -j3 pu
Solution:
Ia1 (pu) = 1/ Z1 +Z2+Z3
= 1 / j0.3+j0.2+j0.1
= -j1.67
37. The electromagnetic torque developed in a motor is 150 N-m. If the field flux
is decreased by 20% and armature current is increased by 15%, find the new
electromagnetic torque developed.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
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PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 138 N-m B. 163 N-m
C. 159 N-m
D. 104 N-m
Given:
Find: T2 (new)
T1:50 N-m
Ia1= 1
Ø1 =1
Ia2:1+.15=1.15
Ø2:1-0.2=0.8
Solution:
T1/T2=(Ø1) (Ia1)/(Ø2) (Ia2)
150/T2= (1) (1) / (0.8) (1.15).
T2=138 N-m
38. A 220 v, 3-phase , 4-wire abc system supplies unbalanced wye-connected
resistance of Ra = 10 Ω, Rb= 15 Ω and Rc= 20 Ω Determine the total power of
the system in watts.
A. 3,495
B. 3,560
C. 3,385
D. 3,895
Solution:
VØ = 220/√3 = 127 02 v
Pa = VØ/ Ra = 127. 022/ 10= 1,613.40
Pb = VØ/ Rb= 127.02 2 /15 = 1,075.60
Pc = VØ/ Rc= = 127.02 2 /20 = 806.70
Pt= 1,613.40 +1,075.60 +806.70
Pt= 3,495.70
39. A coil of wire of 100 turns enclosing an area of 0.09 m 2 has its plane
perpendicular to a uniform magnetic field of flux density 0.5 T. the coil is turned to
position wherein its plane is parallel to the magnetic field in 0.05 sec. Find the
average emf generated in the coil in volts.
A. 15
B. 10
C. 12 D. 9
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
e= 0.0045
Solution:
e = N dd/dt
Ø=ß∆
e= 100 (0.045/ 0.5)
= (0.5) (0.09)
e=9v
Ø = 0.0045
40. A 10-hp, 230 v, three-phase Y-connected synchronous motor has a
reactance of 3 ohms per phase a negligible resistance. To what voltage must the
motor be excited to deliver full-load at unity power factor and 90% efficiency?
A. 242 v
B. 254 v
C. 262 v
D. 248 v
41. To a series RLC circuit, a voltage of 10 v is applied. If Q of the coil at
resonant frequency is 20, the voltage across the inductor at resonant frequency
will be.
A. 200 v
B. 100 V
C. 75 v
D. 50 v
Solution:
QFactor = EL / ET
20 = EL/10
EL = 200 V
42. One advantage of distributing the winding in alternator is to
A. Reduce harmonies
C. reduce the amount of cooper
B. improves voltage wave fromD. decreases the value of the voltage
43. A dc shunt motor running at 1,200 rpm has armature resistance of 0 15 Ω
The current taken by the armature is 60 A when the applied voltage is 220 v. If
the load is increased by 30%, find the variation in the speed.
A. 1,040 rpm
B. 1,162 rpm
C. 1,110 rpm
D. 1,184 rpm
44. the capacitance between any conductors of a three-phase, three-conductor
cable is 2 µF. The cable operates at 11 kV line voltage and 50 HZ. What is the
charging current through the cable capacitance?
A. 7.98 A
B. 3.99 A
C. 6.91 A
D. 13.82 A
45 The per unit reactance’s of a synchronous generator are X d= 1, Xd1 = 0.35,
and xd11 = 0.25. The generator supplies at 1.0 per unit load at 0.8 power factor
lagging. Calculate the voltage behind the subs transient reactance.
A. 1.79 pu
B. 1.24 puC. 1.17 pu
D. 1.59 pu
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
46. A series RLC circuit has a Q of 5 at its resonance frequency of 100 kHZ.
Assuming the power dissipation of the circuit is 100 w when drawing a current of
0.4 A, determine the capacitance C of the circuit.
A. 2.04 nF
B. 2.32 nF
GIVEN:
Q=5
F = 100 X 103Hz
P = 10W
I = 0 8∆
C =?
SOLUTION:
Q=
R=
S=
;
Xc = 781.25
Xc =
;
782.25
=
(
)( )
𝐶
C. 3.02 nF
D. 2.54 nF
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
47. An iron ring of circular cross-section of 5 x 10-4 m2 has a mean circumference
of 2 m. It has a saw-cut of 2 x 10-3 m length and is wound with 800 turns of wire.
Determine the exciting current when the flux in the air gap is 0.5 x 10 -3 Wb. Given
µr of Iron = 600 and leakage factor is 1.2. Assume areas of air gap and iron are
same.
A. 2.95 A
B. 3.95 A
C. 4.95 A
D. 5.95 A
48. A 50 hp, 440 v, 60 HZ, 3-phase motor operates at full-load with an efficiency
of 89% and power factor of 0.85 lagging. Determine the capacitance in µf per
phase of wye-connected capacitor bank to be connected across the motor
terminals to improve the power factor to 0.95 lagging.
A. 148
B. 167 C. 188
D. 210
49. Impurities in an electrolyte can cause an internal short circuit condition called
A. depolarization
B. electrolysis
C. local actionD. polarization
50 A dc constant voltage source feeds a resistance of 2,000 kΩ in series with a
5µF capacitor. Find the time taken for the capacitor when the charge retained will
be decayed to 50% of the initial value, the voltage sourcing being short circuited.
A. 11
B. 12
C. 10
D. 14
51. A resistance of 40 ohms and inductance of 79.6 mH are connected in parallel
across a 240 v, 60 HZ ac supply. Find the total current in amperes.
A. 11
IT= V/Z
B. 12
XL= WL
XL = 2∏ 60 79 6 mH
XL = 30 008 Ω
Z = RXL___
√R2+ XL 2
Z = 40(30.008)
√ 402 + 30.0082
Z=24.004
IT = 240/24.004 = 9.998 or 10 A
C. 10 D. 14
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
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PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
52. A 230 v, 3-phase source supplies a balanced delta connected in parallel
across a 240 v, 60 HZ ac supply. Find the total current in amperes.
A. 33.1
B. 39.8
C. 26.5
D. 29.3
SOLUTION:
IL= √3 Vp = √3 230
Z
8 – j6
IL = 39.8
53. Three unbalanced 3-phase currents are given as follows:
Ia= 10 -30° A , Ib= 0 and Ic= 10 -150° A. Find Ic1A. 3.34 150° A B. 3.34 -150° A
C. 3.34 210° A
D. 3.34 -135° A
SOLUTION:
Ia1 = 1 {(Ia+a(Ib)+a2(Ic)}
= 1{(10<-30) + (1<120(0) + (1<240) (10< -150))}
= 3.34<300∆
IC1= a(Ia1)
=(1<120)(3.34<30) =3.34<1500A
54. Two straight parallel wires 2 m long, 3 mm apart carries a current of 8 A in
opposite direction. Calculate the force between these conductors.
A. 8.25 x 10-3 N
B. 8.75 x 10-3 N
-3
C. 8.33 x 10 N
D. 8.53 x 10-3 N
SOLUTION:
F=(2X10-7) (I1I2) ( )
F=(2X10-7)(8X8)(
)
-3
F= 8.53X10 N
55. A three-phase, 6-pole, 50 HZ, induction motor develops a maximum torque of
30 N-m at 960 rpm. Calculate the torque produced by the motor at 6% slip. The
rotor resistance per phase is 0 6 Ω
A. 24.7 N-m
B. 25.7 N-m
C. 26.7 N-m
D. 27.7 N-m
Tout =Tdev. – Tloss
Ns = (120) (50)
6
=1000
Nr = (1000) (1-0.06)
= 940 rpm
Tdev = 9.55 Pm
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
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PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
N
30 = 9.55Pm
960
Pm = 3015.71 w
Pr = Pm = 3015.71 Pr= 3208.20
(1-s)
1-0.06
2
Pr =I (R/S)
I= 17.91
Ploss= I2R = (17.91)2 (0.6)
=192.46
Tloss = 60 Ploss
2π Nr
Tloss = 60 (192.46) (3)
2π 940
Tloss= 5.87
Tout = 30 – 5.87
=24 13
24.7
56. The turn-on voltage of a Ge junction diode is ______volt.
A. 0.7
B. 0.3 C. 1
D. 0.1
= 0.3 V
57. A 40 miles, 60 cycle single phase line consists of two 000 conductors spaced
5 ft apart. Determine the charging current if the voltage between wires is 33 kV.
The diameter of 000 conductors is 410 mils.
A. 3.92 A
B. 2.92 A
C. 1.92 A
D. 4.92 A
58. A transformer has 4% resistance and 6% reactance drop. Find the voltage
regulation at full load 0.8 p.f lagging.
A. 6.8%
B. 5.8%
C. 8.8%
D. 7.8%
SOLUTION:
%Vr=√ cosθ %IR 2 SINθ %IX 2-1
=√ 0 8 0 04 2+(SIN(36.87)+(0.06))2-1
=0.068X100
=6.8%
59. A dc motor takes an armature current of 100 A at 230 v. The armature
resistance is 0 03 Ω The total number of lap connected armature conductors is
500 and the number of poles is 4. The flux per pole is 0.03 Wb. What is the
torque developed by the motor?
A. 242.86 N-m
B. 218.93 N-m
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
C. 238.73 N-m
GIVEN:
I=100A
P=4 T=?
D. 227.54 N-m
SOLUTION:
T=
( )(
V=230V
)(
T=
R=0 03Ω
Z=500Ω
)(
)
( )
T=238.73N-M
60. A 0.5 µF capacitor, an 80 mH inductance and a 500-ohm resistor are
connected in parallel across a voltage source of V = 12 -j6 v. Find the current as
a phasor if the angular velocity is 500 rad/sec.
A. 0.333 92° A
B. 0.333 -92° A
C. 0.333 122° A
D. 0.333 -122° A
IT = V/Z
XL= WL = 500 rad/sec (80x10-3)= 40
XC= 1 = 1/500(0.5 µF) = 4000
WC
Z= RXLXC/√XL2XC2+R2 (XC-XL)2
Z=
500(40) (4000) _________
√ 40 2(4000)2+ (500)2(4000-40)2
Z= 40.27
Ѳ=cos-1(Z/R) = (40.27/500)
=85.38
IT = 12-j6
40.27< 85.38
IT = 0.333 < - 122 A
61. What is the fourth harmonic of 800 KHZ?
A. 200 KHZ
B. 400 KHZ
C. 3.20 MHZ
D. 4.00 MHZ
F4= F(n) = 800KHZ(4) = 3.2MHZ
62. A mode of communications in which either party can hear while taking, thus
allowing one party to instantly interrupt the other at any time, is called
A. Half simplex
C. Full simplex
B. Half duplex
D. Dull duplex
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
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PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
63. suppose a cell of 1.5 v delivers 100 mA for 7 hours and 20 minutes, and the it
is replaced. How much energy is supplied during this time?
A. 0.49 Whr B. 1.1 Whr
C. 7.33 Whr D. 733 mWhr
W(energy) = Pt =(1.5v)(100x10-3)(7+ ) = 1.1Whr
64. A device that repeatedly reverse the polarity of a magnetic field in order to
keep a dc motor rotating is known as
A. a solenoid
B. an armature coil
C. a commutator
D. a field coil
65. Find the cross-sectional area of the core of a 10 turns transformer for a
voltage of 50 v at 50 HZ. The flux density is 0.9 Wb/m2.
A. 0.025 m2 B. 0.046 m2
C. 0.065 m2
D. 0.085 m2
SOLUTION:
GIVEN:
N=10, V=50v, f=50Hz, Ø=0.9Wb/m2
A=
=
(
)(
= 0.025m2
)
66. The rotor resistance of an 8-pole, 50 HZ, wound rotor induction motor is 0.5
Ω per phase The speed of the motor is 720 rpm at full load Determine the
external resistance to be connected with the rotor circuit to reduce the speed to
680 rpm for full-load torque.
2 Ω B 1 1625 Ω
C 0 5225Ω
SOLUTION:
P=8, f=50Hz, ZØ=0 5Ω, N1=720rpm, N2=680rpm
Ns1=(120(50)/8) = 750rpm
s=(750-680/750) = 0.04
S2/S1 = R2/R1
D 0 8625 Ω
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
S2=750-680/750 = 0.093
0.093/0.04 = R2/0.5
R2 = 1 1625Ω
Re = 1.11625 – 0.5 = 0.6625
67. 87 is the device function number assigned by ANSI to this relay;
A. lock out relay
B. undervoltage relay
C. directional relay
D. differential relay
68. A series RL circuit is connected across a dc source through a switch. Three
milliseconds after the switch is closed, the voltage across the inductance is 20 v
and drops to 5 v after ms. If R = 100 ohms, find L. Assume at t = 0, i = 0.
A. 1.59 H
B. 1.30 H
C. 1.22 H
SOLUTION:
R=100Ω, V=20V, V 3 =5V, t=0, i=0
E=Ee-(R/L)t
20=Ee-(100/L)(.003) – Eq. 1
5=Ee-(100/L)(.025) – Eq. 2
Divide Eq.1 by Eq. 2
20 = Ee-(100/L)(.003)
5
Ee-(100/L)(.025)
4 = e-(.3/L)
e-(2.5/L)
4e-2.5/L=e-.3/L
Ln4 – (-2.5/L) = (-0.3/L)
L = 1.59 H
D. 1.25 H
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
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PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
69. A generator rated 600 KVA, 2,400 v, 60 HZ , 3-phase, 6-poles and wyeconnected has 10% synchronous reactance. If a three-phase fault occurs, what
will be the short circuit current?
A. 1, 443 A B. 1,532 A
GIVEN:
C. 1,435 A
D. 1,426 A
SOLUTION:
Sb=600KVA
I F=
V=2,400V
IF=√
f=60HZ
(
)
( )
(
)(
)
IF=1443 A
P=6
IF=?
70. A coil of inductance 8 mH, produces 80 µWb of magnetic flux. Of this total
flux, 60 µWb are linked to a second coil of inductance 2 mH. How much is the
mutual inductance between coils?
A. 2 mH
B. 3 mH
C. 4 mH
D. 5 mH
SOLUTION:
K=
=
K=0.75
M=K√L1L2
=0 75√ 8X10-3)(2X10-3)
=3X10-3H = 3MH
71. Wind mils in addition to proper gearing is the best driver for
A. dc generator
B. synchronous generators
C. inductance generators
D. rotary rectifiers
72. A rectangular bus bar is made of aluminum and is 90 cm long, 10 cm wide
and 1 cm thick. If the bus bar current flows along its length, find the bus bar
conductance provided the bus bar conductivity is 3.6 x 108 s/m.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 0.4 x 106 s
s
G=
=
(
B. 0.4 x 105 s
)(
)(
)
C. 0.5 x 106 s
D. 0.5 x 105
= 0.4 x 106 s
73. An energy source supplies 500 J of energy at 100 v for a certain period of
time. Determine the quantity of charge passed through.
A. 0.2 c
D. 5 c
B. 50 kc
C. 20 c
SOLUTION:
W=Pt
W=Ivt
Q= =
= 5C
74. A 220 v, 3-phase supply has a balanced delta connected load with
impedance of 15 + j20 ohms/phase. What is the total real power of the load in
watts?
A. 5,133.3
B. 4,122.5
C. 2,965.6
D. 3,484.8
GIVEN:
V=220
ZØ=15tj20Ω=25<53 13
SOLUTION:
P=3( COSØ)
P=3(
𝐶
(
))
P=3,484.8W
75. In a 3-phase, 4-wire system, the current in line A has Ia1 = 200 0° A Ia2
=100 60° A, the current through the neutral conductor is 300 -60° A. Find the
line current Ibin amperes.
A. 300
GIVEN:
120°
B. 300 -60°
SOLUTION:
C. 300
240°
D. 100 -30°
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Ia1=200<0
In= BIao
Ia2=100<60
Iao=100<-60
In+300<-60 Ib=100<-60+(1<240)(2)(1<120)(100)
Ib=?
Ib=300<-120+360
Ib= 300<240
76. Calculate the no-load current taken by a 100 kW, 460 v, shunt motor
assuming the armature and field resistance to remain constant and equal to 0.03
Ω and 46 Ω, respectively The efficiency at full load is 88%
A. 23.5 A
B. 24.5 A
Pʟ = 100 kw
C. 26.0 A
D. 28.0 A
Since Ra and Rs are constant
SPʟ = Pʟ - Po = 100 x 103 – 0.88 (100x103) = 12,000
Vʟ = 460 V
watts
SPʟ = Vʟ Ia-Ia2 Ra
Ra = 0 03 , Rs = 46 Ω
12,000 = 460 (Ia) – ( Ia2 (0.03)
Ia = 26.13 A = Iʟ
77. A 100 MW hydroelectric station is supplying full load for 10 hrs in a day .
Calculate the volume of water which has been used. Assume effective head of
the water as 200 m and the overall efficiency of the station as 80%. Assume 1 m 3
of water = 1,000 kg.
A. 2,232,435 m3
B. 2,345,456 m3
C. 2,293,560 m3
D. 2,371,402 m3
Pt = Q8hn
Q=
(
)(
(
)(
)(
)
)
= 2,293,577.98 m3
78. The dc generator used as pilot exciter is
A. series
B. Shunt
C. over compound
D. flat compound
79. A lead storage battery is rated at 12 volts. If the internal resistance is 0.01
ohm, what is the maximum power that can be delivered to the load?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 1,200 w
B. 1,800 w
V = 12 volts
P=
=
(
C. 3,600 w
)
D. 7,200 w
= 3600 W
R = 0 01 Ω
80. Bundled conductors in EHZ transmission lines results to
A. reduce capacitance
B. increase inductance
C. increase capacitance
D. increase resistance
81.The per unit impedance of a circuit element is 0.30. If the base KV and base
MVA are halved, then the new value of the per unit impedance of the circuit
element will be,
A. 0.30
Xpu2=Xpu1(
B. 0.60
)2(
C. 0.0030
D. 0.0060
)
Xpu2=0.3 ( )2 ( ) ; xpu2=0.60
82. What should be the turns ratio of a three-phase transformer to transform
10,000 KVA from 230 KV to 4,160 V if the transformer is to be connected ∆-Y?
A. 94
a=
B. 96
=
C. 97
D. 98
(√ )
a = 96
83. The input power to a 600-v synchronous motor is measured by means of a
two-method. One wattmeter reads 64 kW and the other reads 36.5 kW. The
motor is known to be operating at leading p.f. Determine the line current drawn.
A. 110 A
B. 104 A
C. 112 A
D. 107 A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SOLUTION:
√ (
Ø=tan-1(
(
)
)
)
Ø=25.360
W=VLILCOS(30-Ø)
64X103=(600)(IL)COS(30-25.36)
IL=107
84. A power plant has an overall efficiency of 30%. If this plant can consume
4,200 kilograms of coal per hour, estimate the total electric energy produced in
one day. Assume the calorific value of the coal being used is 8,000 kcal per
kilogram.
A. 183 MWHR
B. 168 MWHR
C. 176 MWHR
D. 155 MWHR
Win = 4200 kg/hrs x 5000 kcal/kg x 24hrs
Win = 504 x 106kcal x
= 586.05 MWHR
Wouth = n (Win) = 0.3 (586.05 MWHR) = 175.81 MWHR
85. Four lamps are suspended 6 m above the ground at the corners of a lawn 4
m on each side. If each lamp emits 250 cd, calculate the illumination at the
center of the lawn.
A. 20.56 lux B. 21.62 lux
C. 19.85 lux
d2=(2)2+(2)2+(6)2=44
d=6.63
Et= 4 EACH LAMP
= 4 ( )COSØ=4(
=20.56LUX
)(
)
D. 22.34 lux
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
86. A 170-mile, 230-kV, 60-HZ, three-phase single-circuit transmission line uses,
a triangular arrangement with 20 ft. 20 ft, and 36 ft spacing respectively. If the
line conductors have a GMR of 0.0217 ft, determine the capacitive susceptance
to neutral per mile.
A. 4.81 x 10-5 mho per mile
B. 12.74 x 10-6 mho per mile
Dm = √
= 24.33 ft
(
Cn =
Xc =
C. 7.92 x 10-5 mho per mile
D. 2.47 x 10-6 mho per mile
)
(
=
)
(
= 7.922 x 10-12 F/m x
)(
= 1.275x10-8 F/mile
)
Xc = 208091.59 Ω-mile
= 4.81 x 10-5
87. The surge impedance of an underground cable is around
A 50 Ω
B 2 Ω
C 400Ω
D. 100 Ω
88. A process equipment contains 100 gallons of water at 25°C. It is required to
bring it to boiling in 10 minutes. The heat loss is estimated to be 5%. What is the
kW rating of the heater?
A. 50.5 kW
B. 252 kW
C. 125 kW
D. 207 kW
V = 100 gallons
Pt eff = mCΔT
T = 25°C
P=
(
)(
(
)(
)(
)
)
T = 100°C @ 10 minutes
(eff)= 0.95
P = 208.47 KW
89. A 500 MCM ACSR cable has 37 strands. Determine the diameter in mils of
each strand.
A. 116.25
B. 118.34
C. 110.35
D. 120.24
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Aт = 500 MCM
Astrands =
= 13513.51 CM
N = 37 strands
d=√
= √
= 116.25 mils
90. A contact device installed at the outlet for the connection of a single
attachment plug.
A. pendant
B. switch
C. receptacle
D. plug
91. An 8-pole lap wound dc generator has 1,000 armature conductors, flux of 20
mWb per pole and emf generated is 400 v. What is the speed of the machine?
A. 1,000 rpm
B. 1,800 rpm
C. 1,200 rpm
D. 1,500 rpm
N = E(60)a / PZ0
N = 400(60)(8) / 8 (1000) (20x10-3)
N = 1200rpm
92. An air cored coil has 500 turns. The mean length of magnetic flux path is 50
cm and the area of cross-section is 5 x 10-4 m2. If the exciting current is 5 A,
determine the flux density.
A. 3.1415 x 10-3 T
B. 3.1415 x 10-4 T
C. 6.283 x 10-3 T
D. 6.283 x 10-4 T
Given:
Solution:
N = 500
L = 50 cm to 0.5 m
A = 5 x 10-4 m2
I = 5A
H = NI / L = 500 (5) / 0.5 = 5000
B = uH = 4π x 10-7 x 5000
B = 6.283 x 10-3T
93. In a balanced, 3-phase, wye-connected voltage source with phase sequence
abc, Vab= 10° v. Find the phase voltage Von.
A. 230 -230°v
B. 132.8 -80°v
C. 132.8 -140°v
D. 132.8 -260°v.
Vab = <10°
Assume 230v
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
230 / √3 <10
Von = 132.8<10°-270°
Von = 132.8<-260°v
94. When carrier wave is modulated at 100%, its power is increased by ____
percent.
A. 100
B. 150
C. 50
D. 0
95. A certain amount of fuel can produce 10 quads of energy. In how many days
will the fuel be totally consumed if it is used to satisfy a demand of 10 13 BTU/day
at a power plant with an overall efficiency of 20 percent?
A. 170
B. 180
C. 190
D. 200
96. Differential relays are installed to protect the equipment against.
A. reverse current
B. internal faults
C. overcurrent
D. no voltage
97. A short 3-phase, 3-wire transmission line has an impedance of 3 + j4 ohms
per wire. At the receiving end are connected a 3-phase inductive load drawing
3,500 kW at 0.8 power factor and line to line voltage of 13, 200-volt and a
capacitor bank drawing 150 amperes line current. Calculate the voltage at the
sending end.
A. 13, 808 v
B. 13, 718 v
C. 13, 758 v
D. 13, 658 v
98. A 15 KVA, single-phase distribution transformer has a core and copper
losses at rated condition of 90 w and 300 w, respectively. Determine its
maximum efficiency at 0.707 power factor lagging.
A. 95%
B. 96%
C. 97%
Given:
Solution:
S = 15KVa
Pout = (S) (p.f) = (15KVa)(0.707) = 10605W
Pcu= 300W
Pco= 90W
p.f = 0.707
nmax = ?
D. 98%
nmax= Pout / Pout + Pcu+Pco = (10605 / 10605 + 90 + 300) x
100%
nmax = 97%
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2013
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
99. A three-phase, 400 v 50 HZ induction motor has a speed of 900 rpm on fullload. The motor has six poles. How many complete alternations will the rotor
voltage takes per minute?
A. 30
B. 60
C. 300
Given:
Solution:
N = 900rpm
Ns = 120f / p = 120 x 50 / 6 = 1000 rpm
f = 50 Hz
s = Ns - N / Ns = 1000 - 900 / 1000 = 0.1 or 10%
p=6
f’ = s x f = 0 1 x 50 = 0 5 sec x 60 min = 30 min
D. 600
100. This is the porcelain insulator for the end poles;
A. pin
B. post
C. suspension
D.
akimbo.
MARCH 2014
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1. In television system, channels 2 to 13 are classified as
A. VHF
B. UHF
C. SHF
D. EHF
Sol’n
VHF 2-13 channel
2. Two inductors 20 mH and 10 mH are connected in series carrying current of 1
A. Find the stored energy.
A. 15 mJ
B. 20 mJ
C. 30 mJ
D. 60 Mj
Sol’n
L1=20mH
L2=10mH
LT=30mh
WL= I2 L
WL= (1)(30mH)
WL=15mJ
3. Three capacitors are connected in parallel. C1 = 12 µF, C2 = 10 µF, and C3 =
40 µF. What is the total capacitance?
A. 45 µF
B. 5 µF
C. 10 µF
D. 62 µF
Sol’n
C1= 12µF
C2=10µF
C3=40µF
CT=C1 + C2 + C3
CT= 12µF + 10µF + 40µF
CT= 62 µF
4. For an ac motor, the frequency is 60 Hz and the speed is 300 rpm. What is
the number of poles?
A. 26
B. 24
C. 28
D. 30
Sol’n
F=
P=
P=
(
)(
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
P=24
5. A 240 v balanced 3ɸ source supplies a purely resistive impedance of 11.52
ohms per phase. What is the total power drawn if it is Y-connected?
A. 5 kW
B. 15 kW
C. 20 kW
D. 30 kW
Sol’n
I=
P= √3 VIcosθ
√
I=12 028
P= √3 12 028 240 cos0
P= 5KW
6. Power in a three-phase delta system with balanced load is equal to
√
B √3 VɸIɸ(p.f.)
C. 3Vɸ IL (p.f.)
D. 3VLIL (p.f.)
LIL (p.f.)
Answer
√
LIL (p.f.)
7. What is the minimum number of wattmeters required to measure unbalanced
power for a three-phase system?
A. 2
B. 4
C. 3
D. 1
Answer:
2 wattmeter
8. Form factor is defined as
A. rms value/peak value
B. maximum value/rms value
C. rms value/average value
D. effective value/rms value
Answer:
rms value/average value
9. The value of form factor for a pure sine wave is
A. 1.414
B. 0.707
C. 0.637
Sol’n
Formfactor =
Formfactor= 1.11
=
D. 1.11
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
10. Find the horsepower rating of a motor running at 1,500 rpm and developing a
torque of 105 lb-ft.
A. 22
B. 28
C. 30
D. 36
Sol’n
P=
P=
(
)(
)
P= 30.925 Hp
11. There are two wired A and B. If the resistance of B is R and the diameter of A
is twice of B, the length and the nature of the material is the same, find
resistance of A.
A. R/2
B. R/4
C. 4R
D. 2R
12. The breakdown voltage of the dielectric of a cable is 800 volts/mil. A factor of
safety of 4 is used. Find the maximum voltage at 3.5 mils.
A. 2,800 v
B. 700 v
C. 3,600 v
D.
900v
Soln:
13. A wire has a resistance of 1 Ω If the length is increased four times and the
area is doubled the original, find the new resistance of the wire.
A 5Ω
B 2Ω
C 1Ω
D.
0.5
Soln:
(
)
(
*
( *
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
14. The basic function of a circuit breaker is to
A. produce the arc
C. transmit voltage by arcing
B. ionize the surrounding air
D. extinguish the arc
15. Air used in air blast circuit breaker
A. must have least carbon dioxides
B. must be ionized
C. must have oil mist
D. must be free from moisture
16. Two 30 Ω resistances are connected in series. When an unknown resistance
R is connected in parallel with one, the new total resistance is 40 Ω What is
the value of R?
5Ω
B
Ω
C 20 Ω
D
25
Ω
Soln:
17. A 10:1 single-phase transformer is rated 100 kVA 2,400/240 v. When the low
voltage side of the transformer is maintained at 240 v, what is the secondary
impedance?
0.676
B. 0.776
C. 0.576
D.0.876
Soln:
18. What is the counterpart of magnetic flux in an electric circuit?
A. voltage
B. current
C. resistance
D. conductance
19. In a parallel circuit the potential difference across the resistance
A. varies
C. is sometimes constant
B. is different from the applied voltage D. is always constant
20. The rms value of a sinusoidal wave is equal to ______ of maximum value.
A. 0.637
B. 0.707
C. 0.506
D. 1.414
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
21. When one coil of a magnetically coupled pair has a current of 5 A, the
resulting fluxes ɸ11 and ɸ12 are 0.4 and 0.8 mWb, respectively. If the turns are
N1 = 500 and N2 = 1,500, find L2.
A. 530 mH
B. 540 mH
C. 1,060 mH
D. 1,080 mH
22. In two-wattmeter method, the readings of the wattmeters will be identical
when
A. load in one of the phases is zero
C. power factor is 0.5
B. power factor is unity
D. neutral is earthed
Answer: B. Power Factor is Unity
23. The positive, negative, and zero-sequence reactance of a 20 MVA, 31.2 kV
synchronous generator are 0.3 pu, 0.2 pu, and 0.1 pu, respectively. The
generator is solidly grounded and is not loaded. A line to ground fault occurs
on phase a. Neglecting all the resistances, determine the fault current.
A. 2,916 A
B. 4,374
C. 2,525
D. 5,050
24. What is the maximum distance between two receptacles in a single family
dwelling unit?
A. 1.5 m
B. 1.6 m
C. 1.8 m
D. 2.0 m
Answer: C. 1.8m
25. What is the minimum clearance between the recessed incandescent fixture
and the nearest point of a storage space of a closet?
A. 100 mm
B. 150 mm
C. 200 mm
D. 250 mm
Answer: B. 150mm
26. What is the derating factor in each of 7 to 9 conductors in a raceway?
A. 80%
B. 85%
C. 70%
D. 75%
Answer: C 70% is the derating factor in each 7 to 9 conductors
27. What is the maximum number of conductors in a raceway that does not need
to be derated?
A. 2
B. 3
C. 4
D. 5
Answer: B.3
28. Two electrons have a force of 3.46 x 106 N. What is the distance between
them?
A. 8.1 x 10-7 m
B. 1.8 x 10-7 m
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
C. 8.1 x 10-18 m
D. 1.8 x 10-18 m
Solution.
F=3.46x109
k=9x109
Q= 1.6x10-9
√
(
√
)
m
C.
29. A wire 36 inches long is carrying a current of 1,200 A. Find the flux density in
gauss at a point 12 inches from the wire.
A. 2.40
B. 7.87
C. 6.31
D. 5.52
Solution
u = 4pix10-7
I = 1200A
r = 12inch x
x
(
(
)
)
= .3048m
= 7.87x10-4
30. Four resistances of 10, 20, 30 and 40 ohms are connected in parallel. What is
the equivalent resistance?
A. 100 Ω
B 96Ω
C 36Ω
D. 4.8
Solution
[10-1 + 20-1 + 30-1 + 40-1]-1
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
4.8 ohms
31. A factory works at 400-kW, 0.7 pf lagging. A 200 HP synchronous motor is
connected to the plant to correct the pc to 75% lagging. What should be the pf
of the synchronous motor?
A. 80%
B.89%
C. 91%
D. 95%
Sol’n
Po = 400KW
Pfold = 0.7 lag
Pfnew = 0.75 lag
(
(
Psync = 200HP = 149200W
)
)
(
)
(
149200
(
)
(
)
(
)
)
27.09
(
)
32. A transformer has an impedance of 6%. The X/R ratio is 16. Find the per unit
admittance G+jB.
A. 10.3963 + j1.6634
B. 1.0396 + j16.6342
C. 10.3963 – j1.6634
D. 1.0396 – j16.6342
Sol’n
Z = 6% = 0.06 pu
X = 16R
Z2 = R2 + X2
0.062 = R2 + (16R)2
√
(
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
33. A 120 v dc motors draws 225 A from the supply at a distance of 350 m using
two copper conductors of diameter 0.5 inch and resistivity 10.4 ohm-cmil/ft.
Find the voltage of the supply.
A. 126 v
B. 133 v
C. 138 v
D. 142 v
Sol’n
D=
5 in x 1000mils/1in=500mils
𝐶
(
)
(
)
34. A balanced delta connected load impedance of 15
j18 Ω per phase is
connected across a 230 v, three-phase source. Find the total power
consumed.
A. 10,580 W
B. 1,445 W
C. 4,336 W
D. 3,527 W
Sol’n
(
)
35. 34.5 kV to 69 kV is classified as
A. low voltage
C. high voltage
B. medium voltage
D. extra high voltage
Ans: High Voltage
36. A circuit has a resonant frequency of 4,000 rad/sec and bandwidth of 100
rad/sec. If the resistance is 5 ohms, find the values of L and C.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 50 mH, 1.25 µF
C. 5 mH, 12.5 µF
B. 1.25 mH, 50 µF
D. 12.5 mH, 5 µF
Sol’n
BW = 100 rad/sec
Fr = 4000 rad/sec
R = 5 ohms
(
𝐶
)( )
(
)(
)( )
37. A 10 HP, 230 v, 60 Hz three-phase motor has an efficiency of 90% and pf of
0.85 lagging. What is the capacitance per phase in microfarads to be
connected in parallel with the motor correct the power factor to unity?
A. 258 µF
B. 155 µF
C. 25.8 µF
D. 15.5 µF
Sol’n
V = 230V
Po = 10Hp = 7460W
f = 60Hz
eff = 90%
PFold = 0.85%
(
)
PFnew = 1
( )
Pin = Po/eff
Pin = 7460/0.90 = 8288.89W
C=?
(
)
)
( )).89(tan31.799-tan0)
( (
𝐶
(
)(
)
1/2πfXc= 1/2π 60 11 44
38. Three impedances are in parallel. The currents drawn by the impedances are
Ia= 10 A, Ib = 12 A and Ic = 15 A, respectively. If Iais the reference, Ibleads Ia
by 30º, and Icleads Ia by 45º, what is the total current?
A. 10 0º + 12 30º - 15 45º
C. 10 0º - 12 30º + 15 45º
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
B. 10 0º - 12
30º - 15
Ans: D. 10 0º - 12
30º - 15
45º
D. 10 0º - 12
30º - 15
45º
45º
39. A 99 MHz radio station has a 150 µH inductor, what is the capacitance?
A. 0.0172 pF
B. 17.2 pF
C. 1.72 µF
D. 17.2 µF
Sol’n
L = 150 micro henry
Fr = 99 MHz
√
√(
)( )
40. An aluminum cable has 10 identical strands, a length of 1,500 m and a
diameter of 2.50 mm each. What is the resistance of the cable?
A. 5.63 Ω
B 0 563 Ω
C 8 63 Ω
D. 0.863
Sol’n
L = 1500m
D = 2.50mm
A=
84in x 1000mils/1in=98.4mils
𝐶
41. If the speed of an Induction motor increases, what happens to the rotor
frequency?
A. Increases
C. Does not change
B. Decreases
D. frequency has no relation to the
speed
42. A 230 v shunt motor has a no-load line current of 7 A and a full-load line
current of 46 A. The armature resistance is 0.05 Ω and the shunt field is 75 Ω
Determine the motor efficiency at full load.
A. 81%
B. 84%
C. 87%
D. 85%
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Sol’n:
SPL = VNL – IaNL - (
(
)(
)
)
(
) (
) (
(
)
)
= 84%
43. A 40-m metallic conductor of a cross-sectional area 1 mm2 has a resistance
of 12 Ω Calculate the conductivity of the metal
A. 3.33 MS/m
B. 0.333 MS/m
C. 6.67 MS/m
D. 0.667 MS/m
Sol’n:
(
)
44. The voltage across a 50 µF capacitor rises at constant rate of 10 V/ms.
Calculate the current through the capacitor.
A. 2 mA
B. 5 mA
C. 50 mA
D.500 mA
Sol’n:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
𝐶
𝐶
(
(
)
)
45. Express the current phasor 25
A. 17 68 sin ωt-30º)
C. 35.35 sin ωt-30º)
-30º as instantaneous current.
B. 35.35 sin ωt 30º)
D. 25 sin ωt-30º)
Sol’n:
46. A 7.5 HP, 500 v three-phase induction motor is developing its full-load output
at 960 rpm. The starting torque is equal to the full-load torque. What will be
the starting torque if the supply voltage fall to 400 volts?
A. 35.62 N-m
B. 32.34 N-m
C. 28.27 N-m
D. 32.82 N-m
Sol’n:
47. A light bulb having a tungsten filament, draws 0.5 A at 110 v. the cold
resistance of the filament is 20 Ω at 20 ºC At this temperature the
temperature coefficient of resistance for tungsten is 0.005 ºC -1. Determine the
operating temperature of the bulb.
A. 1,980 ºC
B. 2,080 ºC
C. 2,120 ºC
D. 2,020 ºC
48. One advantage of distributing the winding in alternator is to
A. reduce harmonics
C. reduce the amount of copper
B. improve voltage waveform D. decrease the value of the voltage
49. A single-circuit three-phase line operated at 60 Hz is arranged in a triangular
configuration with distances of 20 ft., 20ft. and 38 ft. between conductors, the
conductors are ACSR Drake with GMR of 0.0373 ft. Find the inductive
reactance per mile per phase.
A. 0.478 Ω
B 0 578 Ω
7 Ω
D 0 678 Ω
50. A 120-v shunt motor has an armature equivalent of 0.5 Ω and a field
resistance of 60 Ω At full-load, the motor takes 10 A and the speed is 1,000
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
rpm. At what speed must this motor may be driven as generator to deliver 10
A to an external load at 120 v?
A. 1,158 rpm
B. 1,086 rpm
C. 1,262 rpm
D. 1,045 rpm
Sol’n:
(
)
(
(
)(
( )(
)(
)
)
)
51. The terminal voltage of a Y-connected load consisting of three equal
impedances of 20 30º Ω is 4 4 kV line to line The impedance in each of the
three lines connecting the load to a bus at a substation is Z L = 1.4 75º Ω
Find the lie to line voltage at the substation bus.
A. 4.52 kV
B. 4.62 kV
C. 4.48 kV
D. 4.58
Sol’n:
kV
, V =4.4kV/&3=2540.34V
√
(
(
) (
)
(
)
)(
)
52. The reactance of a generator designated “X” is given as 0 25 per unit based
on the generator’s nameplate rating 18 kV, 500 MVA The base for calculation
is 20 kV, 100 MVA Find “X” on the new base
A. 0.0405 pu
B. 0.0504 pu
C. 0.0450 pu
D. 0.0540 pu
Sol’n:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
( ) (
( ) (
)u,oldV1/V2^2Sb2/Sb1
)
53. If the voltage is doubled, the ampacity of the conductor ___________.
A. increases
B. decreases
C. doubles
D. remains the same
54. A 20kW, 200 v shunt generator is operated at rated load. If the driving engine
is developing 30 bhp, determine the iron and friction losses. Armature
resistance is 0.05 ohm and shunt field resistance is 50 ohms.
A. 1,340 W
B. 1,039 W
C. 954 W
D. 1,034 W
Sol’n:
Ia = Ia + Ish = 100 + 4 = 104 A
6=22,380 W
+ Ploss
=Pout+Ia^2Ra+Ish^2Rsh+SPL
(
) (
)
( ) (
)
=
(
) (
)
( ) (
)
55. A three-phase alternator has 6 slots per pole per phase. Determine the
distribution factor.
A. 0.977
B. 0.956
C.0.963
D. 0.948
Sol’n:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
slots=6 slots/poles x phase=
(
)
56. The purpose of a grid system is to
A. interconnect the power stations
B. supply energy to remote areas
C. make extra high voltage available to consumers
D. make distribution of energy at reasonable cost
57. As the load is increased the speed of a dc shunt motor will
A. remain constant
C. increase proportionally
B. increase slightly
D. reduce slightly
58. Power in a balanced 3-phase system is measured by the two-wattmeter
method and it is found that the ratio of the two wattmeter readings is 2 is to 1.
What is the power factor of the system?
A. 0.9
B. 0.866
C. 0.82
D. 0.707
59. A 50 HP, 440 v, 3-phase, 60 Hz, 6-pole squirrel cage induction motor is
operating at full-load and 0.8 power factor. The full-load efficiency is 85% and
the percentage slip is 5%. Determine the full-load torque.
A. 214.55 N-m
B. 206.72 N-m
C. 312.47 N-m
D. 323.24 N-m
Sol’n:
(
(
)
)
(
)( )
60. A 170-mile, 230 kV, 60 Hz, three-phase single-circuit transmission line uses a
triangular arrangement with 20 ft, 20 ft and 36 ft spacing, respectively. If the
line conductors have a GMR of 0.0217 ft, determine the capacitive
susceptance to neutral per mile.
A. 4.81 x 10-6 mho per mile
C. 7.92 x 10-6 mho per mile
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
B. 12.74 x 10-6 mho per mile
D. 2.47 x 10-6 mho per mile
61. A series RLC circuit has R = 100 ohms, L = 100 µH and C = 100 pF. What is
the frequency in MHz at unity power factor?
A. 1.59
B. 1.36
C. 15.9
D. 13.6
Sol’n:
R=100 ohms, L=100 µH and C=100 pF
f=
f=
1
2π √ 𝐶
1
2π √
(
)
f = 1.5915 Mhz
62. An impedance draws a current of i = 10 cos ωt - 30º) A from a supply with
voltage e = 220 sin ωt v What is the impedance in ohms?
A. 11 + j19.05
B. 11 – j19.05
C. 19.05 + j11
D. 19.05 – j11
Sol’n:
i = 10 cos ωt - 30º = 10 sin ωt
60º
e = 220 sin ωt
Z= =
(
)
Z = 11 – j19.05
63. A balanced wye – connected load with resistance of 8 ohms per phase and
no reactance is supplied by a 240 v, 3 – phase source. Find the real power of
the load in watts.
A. 6,400
B. 7,200
C. 6,800
D.7,600
Sol’n:
P=(
)2 = 7,200 w
64. If the field of a synchronous motor is under – excited the power factor will be
A. lagging
B. leading
C. unity
D. more than unity
65. Find the efficiency of a 150 kVA transformer at 25% full-load at 0.8 p.f.
lagging if copper losses are 1,600 w at full load and iron losses are 1,400 w.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 96.24%
Sol’n:
B. 94.24%
C. 97.24%
D. 95.24%
Convert kVA to watts:
kVA x p.f.
150 kVA (.8) = 120 kW
Pin = Pout + 2Pcu + 2Pcore
= 120 kW + 2(1600) + 2(1400)
= 126000
η=
η=
x 100 = 95.24%
66. An air gap 1.1 mm long and 40 sq.
circuit. Determine the mmf required
gap.
A. 2.1885 AT
C. 218.85 AT
Sol’n:
R=
(
)
cm in cross-section exists in a magnetic
to create a flux of 10 x 10-4Wb in the air
B. 21.885 AT
D. 2,188.5 AT
= 218.84k
T = RØ = 218.84k (10x10-4)
T = 218.84 AT
67. A three-phase, 440 v, 50 Hz, 6-pole induction motor running at 950 rpm takes
50 kW at a certain load. The friction and windage loss is 1.5 kW and stator
losses = 1.2 kW. Determine the output from the rotor.
A. 42.68 kW
B. 46.48 kW
C. 48.80 kW
D. 44.86 kW
Sol’n:
( )
Ns =
= 1000
S=
= 0.05
Pr = Pin – Pcus = 50 kW – 1.2 kW
Pr = 48.8 kw
Pm = Pr (1-S) = 48.8k (1-0.05)
Pm = 46,360 W
Po = Pm - Pfw
Po = 46360 – 1.5k = 44.86 kW
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
68. In DC machines, lap winding is used for
A. high voltage, low current
B. low voltage, low current
C. high voltage, high current
D. low voltage, high current
69. Wye-wye power transformers are protected by current transformers having
______ connection.
Δ–Δ
B. Y – Δ
C Δ–Y
D. Y – Y
70. What is the overall efficiency of the turbine if the power developed is 12 MW
at a head of 150 meters and the nozzle discharges 10 cubic meters each
second?
A. 70.65%
B. 78.99%
C. 81.55%
D. 89.23%
71. If supply voltage is changed by 5% for a 3ɸ induction motor, its torque will
have a change of
A. 5%
B. 25%
C. 10%
D. 20%
Sol’n
2 (0.05) = 10 %
72. A single phase transmission line has a total impedance of 5 60º ohms and
supplies a total load of 120 A, 3.3 kW and 0.8 power factor lagging. Calculate
the sending end voltage.
A. 3.93 kV
B. 3.62 kV
C. 3.54 kV
D. 3.86 kV
Sol’n
Vs=Vr+Ir Z
Vs=3.3 k+ (120 cis-36.87)(5cis60)
Vs=3858.97 cis 3.5
Vs=3.86kV
73. A 2.3 kV three-phase system supplies 120 – kW, 0.6 p.f. lagging balanced
load. Determine the capacitance in each phase of wye – connected capacitor
bank to adjust the power factor to 0.90 lagging.
A. 51.1 µF
B. 52.2 µF
C. 62.5 µF
D. 78.2 µF
Sol’n
(
)
Cy =
(
)(
)
(
) ( )
y
μF
74. An impedance of 5 – j3 ohms is connected in parallel with an ideal inductor L
across a 110 v, 60 Hz mains. Determine L if the total voltage supplied the
current will be in the phase with the total current drawn.
A. 16.6 mH
B. 19.2 mH
C. 22.1 mH
D. 26.8 mH
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Sol’n
IRC =
L=
= 22cis 35.87
= 22.1 mH
75. The sequence components of the line A current I aare as follows: Ia0 = 14.13
17.34º A, Ia1 = 708.26 -31º A and Ia2 = 2.98 10.06 º A. Find the line current
Ibin amperes.
A. 695 205º A
B. 695 -155º A
C. 695 151º A
D. 695 209º A
Sol’n
Ib = Iao + Ia1 (a2) + Ia2 (a)
Ib = 695 cis -155 A
76. Which of the following equipment is not a part of meggar?
A. hand crank
C. a coil of high inductance
B. moving coil meter
D. gear box generator
77. An industrial plant has an aggregate load of 100 kW. The demand factor is
60%. The average total energy consumption of the plant in one year is 186
MWHR. What is the yearly load factor of the plant?
A. 32.45%
B. 42.25%
C. 38.67%
D. 35.39%
Sol’n
P=100kW
D.F=60%
Pave =186MWHR @ 1year
PL=CL x DF
PL = (1000kW)(0.60)
PL = 60,000
L.F =
L.F =0.35388 x 100 = 35.39 %
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
78. A series RL circuit in which R = 5 and L = 20 mH has an applied voltage e
= 100 50sin ωt 25sin 3ωt, with ω = 500 radians per sec Determine the
power dissipated in the resistor of the circuit.
A. 2510 w
B. 2234 w
C. 2302 w
D. 2052w
79. Two parallel connected loads A and B are supplied by a 440 v, 3 – phase, 60
Hz generator. Load A draws and apparent power of 100 kVA at 0.80 power
factor lagging and load B draws an apparent power of 70 kVA at unity power
factor. Determine the feeder current.
A. 202 A
B. 214 A
C. 212 A
D. 208 A
Sol’n
SA = 100kVa SB = 70 kVA
Pf = 0.8
pf = 1
P T=
cis35.87
PT = 185.81 cis23.81
PT = VL IL cos
)
( )
ST=(
ST = 161.55 cis21.81
IL=
√ (
)
(
)
= 212 cis21.8
80. The armature current drawn by any dc motor is proportional to
A. the voltage applied to the motor
C. the flux required in the motor
B. the torque required
D. the speed of the motor
Sol’n
81. Surge impedance of transmission line is given by
A.√𝐶
B. √𝐶
C.
√
D. √
82. A solenoid 500 cm long and 10 cm in diameter is wound with 1,500 turn. Find
the energy stored in the magnetic field when a current of a 5 A flows.
A. 0.045 J
B. 0.055 J
C. 0.046 J
D. 0.072 J
Sol’n
N1=1500 turns d=10cm L=500cm I=5A
L=
W = (4.44x10-3)(5) 2 = 0.055 J
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
83. A coil of inductance 8 m H, produce 80 µWb of magnetic flux. Of this total flux
60 µWb are linked to a second coil of inductance 2mH. How much is the
mutual inductance between the coils?
A. 3 mH
B. 4 mH
C. 5 mH
D. 2 mH
84. Calculate the capacitance between two parallel plates each of which is 100
cm2 and 2 mm apart in air.
A. 0.443 pF
B. 0.515 pF
C. 0.452 pF
D. 0.502 pF
Sol’n
A =100cm2 , d=2mm x 1cm/10mm=0.2cm
(
C=
)( )(
)(
)
C = 0.4427x10-12 or 0.443 pF
Sol’n
A =100cm2 , d=2mm x 1cm/10mm=0.2cm
(
C=
)( )(
)(
)
C = 0.4427x10-12 or 0.443 pF
85. The potential at the terminals of the battery falls from 9 v on open circuit to 6
volts when a resistor of 10 ohms is connected across its terminals. What is
the internal resistance of the battery?
B 4
C 3
D 2
Sol’n
I=
= 0.6A
Vr = E = Vr
Vr = 9 – 6 = 3V
r= =
= Ω
86. An unshaded lamp is 6 m above the table. It is lowered down by 2 m. By how
much is the illumination on the table increased?
A. 2 times
B. 2.25 times
C. 2.5 times
D. 2.75 times
Sol’n
d =6m
E0 = K x (I/d2)
( )
( )
D2 = 3.79 m
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
87. A three-phase motor driven pump at 1,800 rpm is discharging 500 gpm of
water at a head of 25 meters. The pump efficiency is 75%. Determine the HP
of the motor.
A. 15 hp
B. 12 hp
C. 14 hp
D. 10 hp
88. The reactance of a three – phase alternator is 8%. If the alternator is rated 25
MVA at 13.25 kV output voltage, line to phase, solve for the magnitude of the
fault current generated when a short circuit occurs between 2 phases at the
terminals.
A. 6,704 A
B. 6,135 A
C. 6,808 A
D. 6,458 A
Sol’n
Srated = 25MVA
V rated = 13.25 kV = V flux
I actual =
=628.93
)
( )(
√
I fault = √ (
) = 6808 A
89. For an unbalanced load which connection is suitable?
A. 3 – wire open delta connection
C. 3 – wire delta connection
B. 4 – wire wye connection
D. 3 – wire wye connection
90. An inductor has a value of 44 mH at 60 Hz. What is the inductive
susceptance, stated as an imaginary number?
A. –j0.06
B. j0.06
C. –j17
D. j17
Sol’n
XL=2πfL
XL= 2π 60 44x10-3 = 16 588Ω
Inductive = j
= -j 0.06
91. The meter movement in an illumination meter directly measures
A. current
B. voltage
C. power
D. energy
ANS.: A. current
92. A span of wire 1 km long has a conductance of 0.6 s. What is the
conductance of a span of this same wire that is 3 km long?
A. 1.8 s
B. 0.6 s
C. 0.2 s
D. 0.36 s
Sol’n
dx
( ) = x= 0.2s
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
93. A short 230 kV transmission line has an impedance of 5 cis 78º ohms. The
sending end power is 100 MW at 23 kV and 85% power factor. What is the
voltage at the other end?
A. 225.4 kV
B. 226.3 kV
C. 223.2 kV
D. 228.2 kV
Sol’n
Vs = Vr + Is Z
Is =
√ (
√
)(
)
= 295.32 A
Er = Es – Is Z
= 230 – 295.32(5cis78)
Er = 228.9 = 228.2kV
94. A single – phase load on 220 v takes 5 kW at 0.6 lagging power factor. Find
the kVAR size of capacitor, which may be connected in parallel with this
motor to bring the resultant power factor to unity.
A. 6.64
B. 7.32
C. 8.66
D. 6.26
Sol’n
θ = cos-1 (0.6)
θ = 53 13֯
Q= (
)
= 5000 [tan (53.13) – tan (0)]
Q = 6.67 kVAR
95. A 5 kVA, 2,400 – 120/240 volt distribution transformer when given a short
circuit test had 94.2 volts applied with rated current flowing in the short
circuited wiring. What is the per unit impedance of the transformer?
A. 0.0392
B. 0.0386
C. 0.0415
D. 0.0435
Sol’n
Isc
Ip =
Z=
Zpu =
=
= 2.083A
= 45 22
=
=
(
)
Zpu = 0.0392pu
96. A six – pole, three – phase squirrel – cage induction motor is connected to a
50 – cps supply. At full – load, the rotor’s inducted emf makes 72 complete
cycles in 1 minute. Find the rotor speed.
A. 1,200 rpm
B. 1,124 rpm
C. 1,176 rpm
D. 1,054 rpm
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Sol’n
Nr =
(
)
= 1200
72 cycle /min x
Fr =
(
4320 =
= 12 cycles/sec
)
(
)
Nr = 1176 rpm
97. A 100 µF capacitor initially charged to 24 v is discharged across a series
combination of 1 k resistor and a 200 µF capacitor Find the current after 1
sec.
A. 7.24 nA
B. 7.34 nA
C. 8.43 nA
D. 8.84 nA
Sol’n
98. An electrical insulator can be made a conductor
A. by heating it
B. by cooling it
C. by ionizing it
D. by oxidizing it
ANS.: C. by ionizing it
99. A power plant consumes 100,000 pounds of coal per hour. The heating value
of the coal is 12,000 BTU per pound. The overall plant efficiency is 30%.
What is the kW output of the plant?
A. 205,000 kW
B. 105,500 kW
C. 142,500 kW
D. 175,000 kW
Sol’n
100,000 lb x
1.2x10 ^9BTU=
Po = (351.579)(0.3)
Po = 105,500kW
= 1.2x10^2BTU
= 351.579 MW
100. In a short circuit analysis, the positive, negative, and zero sequence
impedances are 0.20 pu, 0.20 pu, and 0.25 pu, respectively, using a base
MVA of 50. Estimate the fault current on the faulted lines if a line to line fault
at the 138 kV level occurs.
A. 1,204 A
B. 2,718 A
C. 1,569 A
D. 906 A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Sol’n
Iactual =
I=3(
= 209.185
(√ )
) = 906 A
AUGUST 2014
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1. One MWHR is equivalent to___________.
A. 8, 160 calories B. 1,000 KWHR
C. 4, 186 joules
D. 3,412 BTU
2. The current following in L and C at parallel resonance are
A. zero
B. equal
C. infinite
D. different
3. What is the equivalent of acis2 + a + j?
A.1+j
B. 1-j
C.-1+j
D. -1-j
C. infinity
D. zero
4. In a series RLC circuit , i.e resonance is
A.maximum
B. minimum
5. An inductance of 8 mH is in series with the parallel combination of 3 mH and 6
mH. What is the equivalent inductance ?
A.4 mH
B. 6 mH
C. 8 mH
D. 10 mH
Solution:
(
+(
)(
) (
)
)
=
6. The current in RLC series circuit, i.e at resonance is
A. maximum
B. minimum
C. infinity
D. zero
7. What is the maximum distance between two receptacles in a single family
dwelling unit?
A.1.5 m
B. 1.6 m
C. 1.8 m
D. 2.0 m
8. Which of the following plants will take least time in starting from cold conditions to
full-load operation?
A. gas turbine
B. Nuclear power plant
C. steam power plant
D. hydroelectric
9. The Value of mutual inductance in terms of self-inductance of the two coils L1
and L2 is proportional to
A. L1L2
Solution:
B. L1/L2
C.
√
D. √
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
√
10. When one coil of a magnetically coupled pair has a current of 5 A, the result
fluxes
and
are 0.4 and o.8 mWb, respectively. If the turns are N1= 500
and N2= 1,500, find M.
A. 120 mH
B. 20 mH
C.240 mH
D. 40 mH
Solution:
(
)(
)
11. Which of the following relays is used in transformers?
A. Buchholz relay B. Mho relay C. Merz- Price relay D. Translay relay
12. The heat required to raise 1 gram of water at 1 degree Celsius.
A. Calorie
B. BTU
C. joule
D. KWHR
13. In how many years will the energy consumption of the Philippines be quadrupled
at 6.9 percent growth rate?
A. 5
B. 10
C. 15
D. 20
14. Heating value of coal largely depends on
A. Ash content
C. Volatile matter
B. Moisture content
D. Size of coal particles
15. An inductance of 40 mH is connected in series with 300 ohms resistance, At t=0,
the energy stored is 0.96 microjoule. Find the current at t=0.
A. 0.44 x 10^-3 A
C. 13.86 x 10^-3 A
B. 0.22 x 10^-3 A
D. 6.93 x 10^-3 A
Given:
L=40mH
R=300Ω
W=0.96 J
Sol’n.
W=
0.96= (
I = 6.93x
)( )
A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
16. For open circuited condition of Thevenin’s theorem, all sources of emf in the
network are replaced by
A. their internal impendance
C. as a total a big source of emf
B. their internal resistance
D. their internal reactance
17. A hydroelectric generating station is supplied from a reservoir of capacity 5 x
10^6 m at a head of 200 meters. Find the total energy available in KWHR if the
overall efficiency is 75 .
A. 1.044 x 10^6
C. 3.044 x 10^6
B. 2.044 x 10^6
D. 4.044 x 10^6
o ’n:
Weight of water available is W=
x Density
=
=
Electrical Energy Available= WH
=
18. A direct lighting fixture directs at least
A. 90 of the light downward
B. 85 of the light downward
C. 85 of the light upward
D.80 of the light downward
19. One decibel represents a power ratio of
A. 10:1
B. 20:1
C. 2:1
D. 1:26:1
20. A generating station to supply four regions of load whose peak loads are 10 MW,
5 MW, 8 MW, 7 MW. The diversity factor at the station is 1.5 and the average
annual load factor is 60 . Calculate the annual energy supplied by the station.
A. 150.12 x 10^6 KWHR
C. 15.012 x 10^6 KWHR
B. 10.512 x 10^6 KWHR
D. 105. 12 x 10^6 KWHR
Given:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Diversity
= 1.5
Load Factor = 60%=0.6
Annual energy supplied = ?
Sum of individual max. demands =
= 30,000
Max. Demand
=
Annual energy supplied =
=
=
21. Calculate the distance from a normally placed screen a 30 candela lamp be
placed in order that the illumination be 5 lux.
A. 2.45 m
B. 4.45 m
C. 5.25 m
D. 3.77 m
Solution:
d=√
= 2.45 m
22. Semiconductors like silicon and germanium are
A. Tetravalent
B. Monovalent
C. Trivalent D. Pentavalent
23. In a 13.8 KV, 10 MVA base three phase system a phase to phase fault occurs. If
the Thevenin’s equivalent impendance of the system is 2 63 , what is the
magnitude of the fault current?
A. 13,800 A
B. 15,900 A
C. 27,600 A
D. 7,970 A
Solution:
√
√ (
)(
)
( )
24. A 50- KVA single phase transformer has a full-load a copper loss of 560 w and
iron loss of 500 w. Calculate the efficiency at 25 of full-load for a power factor
of 0.8 lagging.
A. 93.9
B. 94.9
C. 95.9
D. 96.9
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
25. A three- phase induction motor is taking 40 kW, the slip being 4 , stator losses
amount to 800 watts, calculate the total power developed.
A. 39.200 KW
B. 40.800 KW
C. 37.632 KW
D. 36.732 KW
Solution:
Pm = Pr-Pcu = 40000-800 = 39,200 (1-0.04
Pm = 37,632 KW
26. A 500 volts 1 synchronous motor is taking 50 amperes at a p.f. of 0.8 leading.
The output is 25 Hp and the effective resistance of the armature is 0.25 ohm.
Find the iron and friction losses.
A. 375 w
B. 650 w
C. 725 w
D. 175 w
Solution:
Pm= VLIL cos theta-(Ip2Ra+Pstray)
25(746) = 500(50)(.8)-(50)2(0.25)-Pstray
Pstray = 725 W
27. What is the copper loss at full-load of a transformer if its copper loss at 7/8th fullload is 4,900 w?
A. 5,600 w
B. 3,750 w
C. 6,400 w
D. 375 w
Solution:
Pcu =4900/(7/8)2 = 6400W
28. If three transformers in
- are delivering rated load and one transformer is
removed, then overload on each of the remaining transformers is ________
percent.
A. 66.6
B. 173.2
C. 57.7
D. 73.2
29. The output of a 200-volt 1 synchronous motor, taking a current of 20 amperes is
4 HP, its effective armature resistance is 0.5 ohm. The iron and friction losses
amount to 400 watts. What is the motor power factor?
A. 0.896
B. 0. 846
C. 0.796
D.0.916
Solution:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Pm = VLIL cos theta-(Ip2Ra+Pstray)
4(746) = 200(20) cos theta- 202(.5)-400
Cos theta = p.f. = 0.896
30. In a half-wave rectifier, if ac supply is 60 Hz, the ac ripple is__________.
A.120 Hz
B. 60 Hz
C. 30 Hz
D. 15 Hz
31. The three unbalanced currents are : Ia= 10cis(-30 ), Ib=0, Ic=10cis150 . Find the
phase C positive sequence current.
A. 5.77 A
B. 5.77cis120
C. 8.66cis120
D. 5.77cis240
Ans. Ia1 = 1/3 [IA+ a IB + a^2Ic]
=1/3 [(10 angle -30) + (1 angle 120) (0) + (1 angle 240) (10 angle 150)]
= 5.77
Ic1 =aIa1 = (1 angle 120) (5.77)
Ic1 = 5.77 angle 240 A
32. A coil of inductance 10 H and resistance 2 ohms is supplied at 20 v, Find the
average emf induced when the circuit is opened if the current fails to zero in
0.5sec.
A. 20V
B. 10V
C. 100V
D. 200V
Ans. L equals 10H
R equals 2
E equals 20 V
I= 0 @ t equals 0.5
i= E/R [1-e ^–R/L (t) answer 200 Volts
33. A 200V, three-phase source is connected to two equal impedance of 7.07 + j7.07
ohms in parallel and with both connected in wye configuration. What is the
current per phase of the combination?
A. -16.26 – j16.26 A
C. 16.26 – j16.26 A
B. 16.26 + j16.26 A
D. -16.26 + j16.26 A
34. A dc machine has 8 poles and a rated current of 100A. How much current will
flow in each conductor at rated condition if the armature is simplex lap wound?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 6.25A
B. 50A
Ans. A = mP = 1(8) = 8
C. 25A
D. 12.5A
Ic = 100/8 = 12.5A
35. A 2-μF capacitor, with initial charge of 100μC is connected across a 100Ω
resistor at t=0. Calculate the time in which the transient voltage across the
resistor drops from 40 to 10 volts.
A. 27.7 ms
B. 0.277ms
C. 2.77ms
D. 277ms
Ans. E0 =Q0/c = 100MC/2MF = 50V
i = E/R =40/100 = 6.4
i 10/100 = 0.1
ERE e^t/RC
0.1 = 0.4 (e ^t/100 (2 x 10^6) )
Answer T = 0.277 ms
36. In parallel RC circuit as the value of frequency increases the power factor _____.
A. Remains the same
C. decreases
B. Becomes unity
D. increases
37. A 400-volt, 50Hz star connected induction motor takes a line current of 50
amperes at a p.f of 0.8 lagging. Three mesh connected capacitors are connected
to raise the p.f to 0.9. Find the value of each capacitor in microfarads.
A. 146.7
B. 48.9
C. 16.3
D. 24.5
Solution:
Cy = Pt(tanteta1-Tanteta1)/squaroot3(VL^2)W\
Cy=(400)(50)(0.8)(Tan(cos^-1(0.8))-Tan(cos^1(0.9)/squareroot3(400)(314)
Cy = 48.9 uF
38. Two capacitors C1 and C2 are placed in series. If C1= 100 F, C2= 50 F, find
the maximum energy stored when a 220 v dc supply is applied across the
combination.
A. 0.107 J
B. 0.507 J
C. 0.807
D. 1.107 J
Solution:
CT = c1(C2)/C1(C2)
= 100(50)/100+50 = 33.33 uF
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
W = ½ CE^2
W = ½ (33.33 uF)(200)
Answer W = 0.807J
39. A 2- element series circuit consumes 700 w and has a p.f of 0.707 leading. If the
applied voltage is v= 141 sin(314t + 30 ), find the circuits constants.
A. R=7.14 , C= 44.6 F
C. R= 71.4 , C= 44.6
B. R= 7.14 , C= 446
D. R= 71.4 C= 446 F
Solution:
P = 700w p.f= 0.707
V =141 sin (314t +30)
W =314
F =50 Hz
Vrms = 141(0.707) = 99.7V
S =700/0.707 angle negative cos^-1(0.707) S = 700-j700,21
R = (141/squaroot2)^2/700.21 =14.2/2 = 7.1
Xc =(141/square root 2)^2/70.21 = 14.2/2 = 7.1
Xc = / 2pi(50)(7.1) =448X10^-6
Answer: R = 7.1 ohms C =448X10^-4
40. Two electrons in a vacuum experience a force of 2 x 10^-15 N. How apart are the
electrons?
A. 2.84 x 10^-12 m
C. 9.6 x 10^-7 m
B. 3.4 x 10^-7 m
D. 5.68 x 10^-12 m
Solution:
Q electron = 1.61X10^-19
F = KQ^2/d^2
d = square roots (1.61X10^-19)(9X10^9)/2X10^-15
Answer d = 3.41X10^-7
41. What is the current per phase in the primary windings of a 3 phase
/ Y
connected 6,600/400 – V 500- KVA, 50 Hz transformer. Neglect no load current.
A. 43.74 A
C. 25.25 A
B. 75. 76 A
D. 14.58 A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
42. It is desired to correct the 2,400 – KVA 0.65 Lagging power factor load in a plant
unity by the installation of a synchronous condenser. Calculate the KVA rating of
the latter.
A. 2,400
B. 1,825
C. 1,560
D. 1,960
43. For a 36-slot 4-pole three phase full-pitch distributed winding, what is the percent
reduction in the generated voltage?
A. 4
B. 3
C.6
D. 5
44. Three 10:1 transformers are connected / Y for stepping up the 2,300 – volt
three-phase source. Calculate the secondary line voltage.
A. 23,000 v
B. 69,000 v
C. 46,000 v
D. 40,000 v
Solution:
2300(5.77)(3)=3918 = 40,000
45. A transformer is rated at 550 / 220 v. With the low voltage winding shorted, it
requires 25 v across the 550 v winding to permit rated current through both
windings of the transformer. Calculate the percent impedance.
A. 4.55
B. 6.55
C. 3.55
D. 5.55
46. A 3- phase overhead transmission line is being supported by three disc
insulators. The potentials across top unit and middle unit are 8 KV and 11 KV,
respectively. Calculate the ratio of capacitance between pin and earth to the selfcapacitance between pin and earth to the self-capacitance of each unit.
A. 0.475
B. 0.775
C. 0.375
D. 0.275
47. This device function is used to reflect back surgest into the line.
A. Choke coil
B. Arc horns
C. Surge depressors
D. Delon gaps
48. A 50 KW carrier is to be modulated to a level of 85 . What is the carrier power
after modulation?
A. 58.8 KW
B. 18 KW
C. 50 KW
D. 42.5 KW
49. What is the device function number of overvoltage relay?
A. 59
B. 76
C. 27
D. 67
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
50. A short 3 line with an impedance of 6 + j8 ohms per line has sending and
receiving end line voltages of 120 and 110 KV respectively for some receiving end
load at a p.f. 0.9 lagging. The active power at the receiving end is nearest to
A. 100,200 KW
B. 200,000 KW
C. 120,000 KW
D. 110,200KW
51. A farmer has a small stream on his property which he thinks might supply
enough power to light his building. The stream is gauged and found to be flowing
0.03m2 per second. The available fall is 2.1m. A small hydraulic turbine and
generator will have a combined efficiency of 70%. Taking the transmission line
efficiency as 80%, how many 50W lamps can be connected to the generator
simultaneously?
A. 5
B. 6
C. 7
D. 8
52. Two long straight conductors each carrying an electric current of 5A are kept
parallel to each other at a separation of 2.5cm. Calculate the magnitude of magnetic
force experienced by 10cm of a conductor.
A. 2X10-3N
B. 2X10-4N
C. 2X10-5N
D. 2X10-6N
Solution:
( )( )
(
)(
)
53. A 400V, 10KW series motor drives a fan when running at 800 rpm. The motor
draws 50A from the supply The resistance of the armature and series field are 0 2Ω
and 0 1Ω, respectively Determine the electromagnetic torque developed by the
motor.
A. 225N-m
B. 230N-m
C. 235N-m
D. 240N-m
Solution:
:
(
)
(
(
)
)
(
)
(
(
)
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
54. The load of a certain transformer is reduced to 50%, the copper loss would
become
A. 0.25 times
B. 0.50 times
C. 2 times
D. same as before
55. At a slip of 4% the maximum possible speed of 3Ø, 60HZ squirrel cage induction
motor is
A. 3,600 rpm
B. 3,456 rpm
C. 3,200 rpm
D. 3,000 rpm
Solution:
(
(
)
)
(
)
56. An electric heater develops a power of 1KW when run on 230V supply. If the
resistance wire of the heater has a diameter of 0.5mm and a resistivity of 60x10 -8Ωm, find the minimum length of the wire required.
A. 11.33 m
B. 13.3 m
C.15.3 m
D. 17.3 m
Solution:
(
(
)
*
57. Each conductor of a horizontally arranged two- conductor bundle line is ACSR,
1,272 MCM Pheasant. The spacing between bundle centers is 8m, 8m and 16m and
between bundle conductors is 45 cm. Find the inductive reactance of the line in
ohms per km per phase if GMR of each conductor is 0.0466 ft.
A. 0.165
B. 0.265
C. 0.365
D. 0.465
58. Shunt generators are used where the main requirement is constant
A. current and voltage
C. voltage over a narrow load range
B. current
D. voltage over a wide load range
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
59. A 4-pole lap-wound armature has 480 conductors and a flux per pole of 25mWb.
What is the emf generated, when running at 600 rpm?
A. 240V
B. 120V
C. 60V
D.30V
Solution:
(
)(
)(
)
60. Transmission voltage level of 1,000kV is categorized as
A. Low Voltage
C. Extra High Voltage
B. High Voltage
D. Ultra High Voltage
61. The efficiency of thermal plant is approximately
A.10%
B. 30%
C. 60%
D. 80%
62. When a line to ground fault occurs, the current in a faulted phase is 100A. The
zero sequence current in the case will be
A. zero
B. 66.6 A
C. 33.3 A
D. 100A
Solution:
63. In which type of faults given below all the 3 components Ia0, Ia1 and Ia2 are equal?
A. Single line to ground fault
C. Double line to ground fault
B. Line to line fault
D. Three phase fault
64. A 220V series motor takes 10A and runs at 600 rpm. The total resistance is
0 8Ω At what speed will it run when a 5Ω resistance is connected in series, the
motor taking the same current at the same supply voltage
A. 456 rpm
B.458 rpm
C. 460 rpm
D. 462 rpm
65. An electric heater takes 1.2 kWhr in 30 minutes at 120V. What is the current
input to the heater?
A. 20 A
B. 15 A
C. 10 A
D. 5 A
Solution:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
( )(
)(
)(
)
66. When the relative permeability of a material is slightly less than 1, it is
called_____ material.
A. non-magnetic B. paramagnetic
C. ferromagnetic
D. diamagnetic
67. A coil of 50 turns having a mean diameter of 3cm is placed coaxially at the
center of a solenoid 60cm long wound with 2,500 turns and carrying a current of 2A.
What is the mutual inductance of the arrangement?
A. 18.5 mH
B. 1.85 mH
C. 0.185 mH
D. 185 mH
68. The rms value of sinusoidal ac current is equal to its value at an angle of ______
degrees.
A. 45
B. 30
C. 90
D. 60
69 Two capacitors of 0 1μF, 250V and 0 2μF, 500V are connected in series What is
the maximum voltage that can be applied across the combination?
A. 375V
B. 750V
C. 250V
D. 500V
Solution:
(
)
(
)(
)
70. A current of 20A flows through two ammeters A and B joined in series. Across A,
the potential difference is 0.2V and across B, it is 0.3V. Find how the same current
will be divided between the two when they are joined in parallel.
A. 10 A, 10 A
B. 12 A, 8 A
C. 14 A, 6 A
D. 16 A, 4 A
Solution:
(
(
)(
)
)(
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
71. An office 17m by 8m wide, is lighted by 8 lamps has a luminous intensity of 200
Cd. Allowing an absorption loss of 4,000 lm for the reflectors, walls and ceiling,
Calculate the average illuminations on the working plane.
A. 147.9 lm/m2 B. 132.6 lm/m2
C. 118.4 lm/m2
D. 112.8 lm/m2
72. One of the advantages of distributing the winding in alternator is to
A. reduce harmonics
C. reduce the amount of copper
B. improve voltage waveform
D. decrease the value of the voltage
73. A circuit breaker will normally operate
A. when the switch is put on
C. when the power is to be supplied
B. when the line is to be checked
D. whenever the fault in line occurs
74. Two-wattmeters can be used to measure three-phase power for a
A. balanced and unbalanced load
C. balanced load only
B. unbalanced load only
D. unity power factor only
75. A shunt motor runs at 500 rpm on a 200V circuit Its armature resistance is 0 5Ω
and the current taken is 30A in addition to field current. What resistance must be
placed in series in order that the speed may be reduced to 300 rpm, the current in
the armature remaining the same.
A 4 37 Ω
B. 3 37 Ω
2 47 Ω
D 1 47 Ω
Solution:
Eb1/N1 = Eb2/N2
Eb1= 200- (30) (0.5)
= 165V
Eb2 = 185 (300) / 500
= 111V
Ia2 = 111-200/-30
2 7 2 47
76. A transformer has 4% resistance and 6% reactance drop. Find the voltage
regulation at full-load unity power factor
A. 2%
B. 3%
C. 4%
D. 5%
77. What is the nature of the current flowing in the armature of dc machine?
A. pulsating dc
B. pure dc
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
C. rectified ac
D. alternating current
78. The current in the circuit is given by i=50sinωt If the frequency be 25Hz, how
long will it take for the current to rise to 25 amp?
A. 0.02 sec
B. 3.33x10-3 sec
C. 0.05 sec
D. 0.033 sec
79. A single phase transformer when supplied from 220V, 50 Hz has eddy current
loss of 50W. If the transformer is connected to a voltage of 330V, 50Hz, the eddy
current loss will be
A. 168.75W
B. 112.5W
C. 75W
D. 50W
Solution:
Peddy = ke(Eg) = (1.033) (330)² = 112.494W
80 The resistance of the field coil of a motor is 200Ω at 15 . After the motor worked
for a few hours on full load, the resistance increases to 240Ω Calculate the
temperature rise of the load coil assuming the temperature coefficient of resistance
is 0.0042 per at 0 .
A. 20.6
B. 30.6
C. 40.6
D. 50.6
Solution:
t1 = 1/t0+T =
(
)
= 3 951X10ˉ³ ; R = R1
1
(X))
240 = 200 (1 3 951X10ˉ³X ;
X = 50.62 °C
81. A magnetic field exist around
A. copper
B. moving charges
C. iron
D. aluminum
82. Inductance affects the direct current flow at the time of
A. turning on and off
C. turning on
B. operation
D. turning off
83. A power plant is said to have had a use factor of 48.5% and a capacity factor of
a 42.4%. How many hours did it operate during the year?
A. 7,660
B. 8,660
C. 5,660
D. 6,660
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Solution:
84. Surge impedance of transmission line is given by
A √C/L
B √CL
C 1√L/C
D √L/
85. In a radio a gang condenser is a type of
A. air capacitor
B. paper capacitor
C. ceramic capacitor
D. electrolytic capacitor
86. A single- phase transmission line has a total resistance of 1 5Ω and a loop
reactance of 0 3Ω It delivers 2MW at 11kV at a power factor of 0 8 lagging.
Calculate the line voltage at the sending end.
A. 11.21kV
B. 11.11kV
C. 11.41kV
D. 11.31kV
87 Three 40Ω non-inductive resistances are connected in delta across 200V, 3phase lines. Calculate the power taken from the mains if one of the three resistors is
disconnected.
A. 500W
B. 1,000W
C. 1,500W
D. 2,000W
Solution:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
88. Power in a balanced three-phase system is measured by the two wattmeter
method and it is found that the ratio of the two readings is 2:1. What is the power
factor of the system?
A. 0.5
B. 0.8
C. 0.866
D. 1
Solution:
=
√
=
=
√
89. A material commonly used for shielding or screening magnetism is
A. brass
B. aluminum
C. copper
D. soft iron
90. One advantage of secondary cell is that it
A. can be recharged
C. it is compact, easy to carry
B. can be used for portable equipment
D. cannot be recharged
91. Calculate the capacitance of a parallel plate capacitor having 20cm x 20cm
square plates separated by a distance of 1mm. Assume the dielectric medium to be
air.
A. 3.54pF
B. 35.4pF
C. 354pF
D. 3,540pF
Solution:
( )(
)
92. Calculate the self-inductance of an air-cored solenoid, 40cm long having an area
of cross-section 20cm2 and 800 turns.
A. 2.42mH
B. 4.02mH
C. 5.20mH
D. 6.40mH
Solution:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
( )(
)(
)
93. A three-phase induction motor having an input power of 30KW running at a slip
of 4%. The stator loss is 1KW and friction and windage loss is 1.5KW. Determine the
motor efficiency.
A. 86.8%
B. 87.8%
C. 88.8%
D. 89.8%
94. An iron core has a cross-section of 500mm2and having a length of 100cm. A
magnetizing force of 500AT in it produces a magnetic flux of 400µWb. Determine the
relative permeability of the material.
A. 1,275
B. 1,250
C. 1,225
D. 1,200
Solution:
(
)(
)( )(
)
95. Find the capacitive susceptance per mile of single-phase line operating at 60Hz.
The conductor is partridge with an outside diameter of 0.642in and spacing is 20ft.
between centers.
A. 4.10x10-6 mho/mile to neutral
C. 5.10x10-6 mho/mile to neutral
-6
B. 4.90x10 mho/mile to neutral
D. 5.90x10-6 mho/mile to neutral
96. The reactance generator having a subtransient reactance of 0.15pu and
operating at 5 percent above its rated voltage supplies a synchronous motor having
a 0.2pu subtransient reactance. The motor is connected to the generator by a
transmission line and a transformer of total reactance 0.305pu. A sudden threephase short circuit occurs at the generator terminals. Determine the per unit
subtransient fault current.
A. –j6.443pu
B. –j7.443pu
C. –j9.079pu
D. –j10.079pu
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2014
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
97. A synchronous generator having a subtransient reactance of 0.15 pu and
operating at 5 percent above its rated voltage supplies a synchronous motor having
a 0.2 pu subtransient reactance. The motor is connected to the generator by a
transmission line and a transformer of total reactance 0.305 pu. A sudden threephase short circuit occurs at the generator by a transmission line and a transformer
of total reactance of 0.305 pu. A sudden three phase short circuit at the generator
terminals. Determine the per unit subtransient fault current.
A. –j6.443 pu
B. –j7.443 pu
C. –j9.079 pu
D. –j10.079 pu
98. What type of core is used for a high frequency transformer?
A. Air core
B. Aluminum core
C. Closed iron core
D. Open iron core
99. For a single line to ground fault the zero sequence current is given by j3.0pu.
The current carried by the neutral during the fault is
A. j1.0pu
B. j3.0pu
C. j9.0pu
D. j6.0pu
Solution:
(
)
100. An inductor supplied with 100V ac with a frequency of 10kHz passes a current
of 10mA. The value of inductor is
A. 1.7 mH
B. 16 mH
C. 1 mH
D. 160 Mh
Solution:
MARCH 2015
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1. A material best suited for manufacturing of fuse wire is
A. Aluminum
B. Silver
C. Lead
D. Copper
2. In the Fleming’s left hand rule, thumb always represents
A. voltage
B. current
C. direction of force on conductor
C. magnetic field
3. The net reactance in a series RLC circuit is
A. XL
B. XC
C. XC + XL
D. XL – XC
4. Two resistors R1 and R2 are connected in parallel. R1 is twice of R2. If
the current in R1 is I, what is the current in R2?
A. I
B. 2I
C 4I
D. I/2
SOLUTION:
R1 = 2 R2
I2 = I (2R2) / R2
If R1 = I
I2 = 2I
V1 = V2
I1 R1 = I2 R2
5. The ampere-hour capacity of battery depends on
A. The thickness of the plates
B. the strength pf the electrolytes
C. The area of the plates
D. the distance between the
plates
6. A Y-∆ connected transformer has a turns ratio of 1 If the primary line
current is 5 amperes, what is the secondary line current?
A. 5 A
B. 15 A
C. 8.66 A
SOLUTION:
ILA = sqrt(3) x (5 A)
= 8.66 A
D. 2.89 A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
7. In a certain country the energy consumption is expected to double in
10 years. Calculate the growth rate.
A. 4%
B. 3.96%
C. 13.86%
D.6.93%
SOLUTION:
Q = Q0 ekt
2 = I ek(10)
k= 6.93%
8. The condition in Ohm’s Law is that
A. ratio V/I should be constant
B. current should be proportional to voltage
C. the temperature should remain constant
D. the temperature should vary
9. Two single phase transformers with equal ratings and turns ration are
operated in parallel to supply a load of 300 KVA, 0.80 lagging power
factor. Transformer A has a resistance of 2.5% and reactance of 5.5%.
Transformer B has a resistance of 2.0% and a reactance of 5.5%. Find
the KVA load of each transformer.
A. 147.7, 152.2
B. 148.7, 151.5
C. 149.7, 150.5
D. 150.7, 149.5
SOLUTION:
Z1 = sqrt.( 0.0252 + 0.0552 ) = 0.060415
Z2 = sqrt.( 0.022 + 0.0552 ) = 0.058523
S1 = (300)(0.060415 / 0.060415 + 0.058523) = 152.39 kVA
S2 = (300)(0.058523 / 0.060415 + 0.058523) = 147.61 kVA
10. If an electrical network having one or more than one voltage source, is
transformed into equivalent electrical network with a single voltage
source (which is short circuit current of previous circuit) with parallel
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
internal resistance of the network with all current source replaced by
their internal resistance. The above illustration is called
A. Thevenin’s theorem
B. Reciprocity Theorem
o ton’s th o m
D. Superposition theorem
11. What is the power given V = 4 sin3t and I = 4 sin3t?
A. 16 sin(3t)2
B. 16 sin2(3t)
C. 8(1-6cos3t)
D. 16(1-6cos3t)
SOLUTION:
P = (4 Sin 3t)( 4 Sin 3t) = 16 Sin2 3t
12. A 40µF capacitor is supplied with a voltage of v(t) = 100sin377t. Find
the current equation.
A. 1.51sin(377t - 90º)
B. 1.51sin377t
C. 1.51cos(377t+90º)
D. 1.51cos377t
SOLUTION:
40x10-3 ( (100) ( 377 cos 377t) + ( sin 377t) (0)) = 1.51 cos 377t
13. A 20mH inductor draws a current of i(t) = 100sin100t. Find the voltage
equation.
A. 200sin100t
B. 200cos100t
C. 2000sin100t
D. 2000cos100t
SOLUTION:
20x10-3 ( 100(100 cos 100t) + (sin 100t) (0)) = 200 cos 100t
14. For a three phase unbalanced load
A. The power factor of each phase will be proportional to the load
B. The power factor each phase will be the same
C. The power factor of at least one of the phases must be leading
D. The power factor of each phase may be different
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
15. Cellular phones operate in the frequency range of
A. EHF
B. VHF
C. UHF
D. SHF
16. A medium unshaded lamp hangs 8 m directly above the table. To what
distance should it be lowered to increase the illumination to 2 times its
former value?
A. 2.34 m
B. 5.66 m
C. 4 m
D. 4.64 m
SOLUTION:
E1 / 2 E1 = (d2 / 8)2
d2 = 8 ( sqrt.(1/2)) = 5.66 m
17. The resistance of a copper wire at 30ºC is 50Ω If the temperature
coefficient of copper at 0ºC is 0.00427, what is the resistance at
100ºC?
A. 72 26 Ω
B
24 Ω
C 54 25 Ω
D 58 15 Ω
SOLUTION:
T = 1 / ɑ = 1 / 0 00427 = 234 19 deg C
R2 = ((100 + 234.19) / (30 + 234.19)) (50) =
2 Ω
18. What is the maximum allowable voltage drop for lighting circuit?
A. 3%
B. 5%
C. 2%
D. 10%
19. What is the maximum allowable voltage drop for feeder?
A. 1%
B. 2%
C. 3%
D. 5%
20. Fiber optic operates on the principle of
A. Refraction
B. Reflection
C. Diffraction
D. Dispersion
21.
color is reserved for grounding equipment wire only.
A. white
B. green
C. yellow
D. grey
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
22. Overhead lines are protected from lighting by the use of
A. I only
B. II only
C. either I or II
D. both I and II
23. An inductance of 20 mH is connected in parallel with a capacitance of
80 µF. What is the frequency when XL = XC?
A. 100 HZ
B. 150 HZ
C. 128.5 HZ
D. 125.8 HZ
SOLUTION:
√
√(
)(
)
24. A horizontal powerline carries a current of 90 A. Compute the magnetic
field at a point 1.5 m below the line.
A. 1.2 x10-5 T
B. 1.2 x10-4 T
C. 1.2 x10-3 T
D. 1.2 x10-2T
SOLUTION:
(
(
)
)(
(
)
)
25. The syncroscope is an instrument used to indicate the
A. Speed of motor
B. Phase relationship between the current and voltage
C. Phase relationship between two voltages
D. Phase relationship between the true power and the reactive power
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
26. A three-phase transmission line of a two-conductor bundle is arranged
horizontally with a spacing of 8 m between bundle centers. Each
conductor is ACSR, 1,272,000 cmils Pheasant with GMR of 0.0466 ft.
the spacing between conductors of bundle is 45 cm. Find the per unit
series reactance of the line if its length is 160 km and base is 100
MVA, 345 KV.
A. 0.069 pu
B. 0.059 pu
C. 0.049 pu
D. 0.039 pu
SOLUTION:
)(
√(
)
√
(
)
(
)(
)
⁄ )
(
(
)(
(
)
)
27. The current flowing in the armature conductors of a dc motor is
A. ac
B. dc
C. ac as well as dc D. transients
28. A string insulator has 5 units. The voltage across the bottom most until
is 30% of the total voltage. What is the string efficiency?
A. 60%
B. 66.67%
C. 75%
D. 83.33%
SOLUTION:
(
)
( )
29. For a single line to ground fault the zero sequence current is given by
j3.0 pu. The current carried by the neutral during the fault is
A. j 1 pu
SOLUTION:
B. j 3 pu
C. j 9 pu
D. j 6 pu
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
(
)
30. Two single-phase transformer are each rated 75 KVA are connected in
V or open delta to serve a 3-phase load of 120 KW at 0.80 power
factor lagging. Determine the size in KVAR of the capacitor needed to
prevent overloading of the transformers.
A. 40.25
B. 41.28
C. 45.24
D. 43.50
SOLUTION:
√
√
√
√
√
(
)
31. A time of 10 milliseconds is required for the current on a series RL dc
circuit to reach 90% of its final steady state value. What is the time
constant in seconds for the circuit?
A. 3.39 ms
B. 4.34 ms
C. 3.86 ms
D. 4.25 mS
32. The armature current drawn by any dc motor is proportional to
A. The voltage applied to the motor
B. the torque required
C. The flux required in the motor
D. The speed of the motor
33. Fault level means
A. Voltage at the point fault
B. Fault current
C. Fault power factor
D. Fault MVA
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
34. A bulb having a rating of 220 volts, 75 watts is to be connected to a
110 volts source. What power will it draw if connected across 110 volts
source?
A. 37.5 watts
B. 9.375 watts
C. 75 watts D.18.75 watts
SOLUTION:
75 watts = 2202 / R
R = 2202 / 75 = 645 33 Ω
P = 1102 / 645.33 = 18.75 watts
35. A capacitor is charged 0.23 watt-second of energy at a voltage of 48
volts. What is its capacitance?
A. 180 µF
B. 240 µF
C. 200 µF
D. 220 µF
SOLUTION:
C = (0.23 (2)) / 482 = 199.65 x 10-6 F = 200 µF
36. A 20-HP, 110 v dc shunt motor has an efficiency of 88% and an
exciting current of 4 amperes and an armature resistance of 0.04 ohm.
What is the starting resistance required for full-load torque?
A.
Ω
B 0 96Ω
C 0 92Ω
D 0 46Ω
SOLUTION:
Po = 20 HP (746 watts) / 1 HP = 14920 watts
Pi = 14920 / 0.88 = 16954.55 watts
37. A coil of 50-ohm resistance and 150 mH inductance is connected in
parallel with a 50 µF capacitor. What is the power factor of the circuit?
A. 70% lagging
B. 70% leading
B. C. 80% lagging
D. 80% leading
SOLUTION:
A = 50 + 2 pi (60) (150 x 10-3)I = 50 + 18 pi i
B = 1 / 2 pi (60) ( 50 x 10-6) (-i) = -53.05 i
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
((50 + 18 pi) (-53.05i)) / (50 + 18 pi) + (-53.05 i) = 79.895 < -45.48
P.F. = cos (45.48) = 0.707 x 100 = 70 % leading
38. A 220-volt dc shunt motor runs at 500 rpm with an armature current of
50 amperes and an armature resistance of 0 1 Ω Calculate the speed
if the torque is halved?
A. 510.8 rpm
B. 508.6 rpm
C. 505.8 rpm
D. 502.8 rpm
SOLUTION:
N2 = (217.5 (500)) / 215 = 505.8 rpm
39. A 150-MVA, 13.8-KV, Y-connected, 3ɸ, 60-HZ alternator is operating
at rated voltage and at no-load when a three-phase faults occurs at its
terminals. If the substransient reactance of the alternator is j0.2 pu,
calculate the current the instant fault occurs.
A. 10,870 amps
B. 6,276 amps
B. C. 32,611 amps
D. 31,380amps
SOLUTION:
I” = 150 x 106 / (sqrt (3)) (13.5 x 103) (0.2) = 31,377.73 A
40. The capacitance reactance of a transmission line is 90,000 ohms per
kilometer. Find the total capacitance reactance if the transmission line
is 50 km long.
A. 90,000 Ω
B. 4.5 x 106 Ω
C 180,000 Ω
D
,
Ω
SOLUTION:
Xc = 90000 / 50 =
Ω
41. A generating station supplies peak load of 12,000 KW, 9,000 KW, and
6,000 KW. Calculate the maximum demand of the station and the
energy supplies in a year if it its diversity factor and its average annual
load factor is 1.2 and 0.7, respectively.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 27,000 KW,137.97 x 106 KWHR
B. B. 22,500 KW, 137.97 x 106 KWHR
C. 27,000 KW, 5.75 x 106 KWHR
D. 22,500 KW, 5.75 x 106 KWHR
SOLUTION:
PL = (12000 + 9000 + 6000) / 1.2 =22,500,000
0.70 = Annual Energy / 22,500 (8760) = 137.97 x 106 Kw-hr
42. If the input of the prime mover of an alternator is kept constant but
excitation is increased, then
A. KVA will be leading
B. KVA will be lagging
C.KW will be changed
D. The p.f. of the load remains
constant
43. A load of 10 ohms was connected to a 12-volt battery. The current
drawn was 1.18 amperes. What is the internal resistance of the
battery?
A. 0 35 Ω
B
7Ω
C 0 25 Ω
SOLUTION:
( )(
(
)(
)
)
44. In electroplating, the positive electrode is called the
D 0 30 Ω
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. cathode
B. anode
C. terminal
D. iontrap
45. The per unit value of a 2-ohm resistor at 100 MVA base and 10 KV
base voltage is
A. 4 pu
B. 0.5 pu
C. 0.2 pu
D. 2 pu
SOLUTION:
(
(
)(
)(
)
)
46. Calculate the mean spherical candle power of a lamp emitting a flux of
1,500 lumens.
A. 119.37 cd
B. 1,500 cd
C. 375 cd
D. 477.46 cd
SOLUTION:
47. A piece of conductor 10 cm long moves across a magnetic field of
10,000 gauss at a velocity of 120 cm/sec. What voltage appears
across the conductor?
A. 0.24 v
B. 60 v
C. 0.12 v
SOLUTION:
(
)(
)(
)(
)
D. 120 v
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
48. A 220 volt, 10 HP, 60 HZ, three-phase induction motor having four
poles is operating at full-load slip of 3%. What is the frequency of the
rotor current at full-load?
A. 60 HZ
B. 18 HZ
C. 1.8 HZ
D. 180 HZ
SOLUTION:
(
)(
)
49. A load of 10 MVA, 0.8 p.f. lagging, 22 KV is served by a transmission
line which has a line resistance of 3 ohms and a line reactance of 10
ohms. Solve for the sending end voltage.
A. 25,972 v
B. 28,721 v
C. 22,433 v
D. 24,214 v
SOLUTION:
(
)
( )
(
)(
)
50. The core loss of a 5 KVA single phase transformer with normal voltage
applied to the primary is 75 watts. The maximum efficiency occurs 60%
of full load KVA. What is the full load efficiency of the transformer at
0.80 power factor?
A. 95.16%
SOLUTION:
B. 93.38%
C. 89.52%
D. 91.36%
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
(
(
)
)
51. The reactance of a generator designated X” is given as 0 25 per unit
based on the generator’s nameplate rating of 18 KV, 500 MVA The
base for calculations is 20 KV, 100 MVA Find X” on the new base
A. 0.0617 pu
B. 0.0405 pu
C. 0.0081 pu
D. 0.0450 pu
SOLUTION:
X”pu new = 0 25 18 / 20 2 (100 / 500) = 0.0405 pu
52. A constant current of 2 A flows through a circuit element. In 10
seconds, how much net charge passes through the element?
A. 0.2 C
SOLUTION:
B. 2 C
C. 20 C
D. 200 C
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Q = 2 (10) = 20 C
53. Compute the resistance of a copper wire having a diameter of 2.05 mm
and a length of 10 m.
A. 52 Ω
B 52Ω
C 0 52 Ω
D
2Ω
SOLUTION:
A = 2.059 (1 / 10) (1 / 2.54) = (0.0807 in x 1000)2 = 6514.10 CM
R = 10.37 (10 (3.28) / 6514.10) =
2Ω
54. What is the capacitance of a parallel-plate capacitor having rectangular
plates 10 cm by 20 cm separated by a distance of 0.1 mm? the
dielectric is air.
A. 17.7 pF
B. 177 pF
C. 1,770 pF
D. 17,700 pF
SOLUTION:
C = (1 (0.02) (8.854 x 1012)) / 1 x 10-4 = 1770.9 pF
55. A wire length 1 m carries a current of 10 A perpendicular to a field of
flux density 0.5 T. Determine the magnitude of the force on the wire.
A. 5 N
B. 50 N
C. 10 N
D. 100 N
SOLUTION:
F = 0.5 (10) (1) = 5 N
56. The apparent power supplied to a load in an ac circuit is 2,000 voltamperes with a power factor of 0.6 lagging. The reactive power is most
nearly:
A. 1,200 VAR
B. 3,333 VAR
C. 1,600 VAR
D.
VAR
SOLUTION:
S= 2000<-cos(0.60) = 2000<-53.13 = 1200 – j 1599.998 VA
Or 1,600 VAR
2,500
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
57. Barrier potential of silicon diode is:
A. 0.1 v
B. 0.3 v
C. 0.4 v
D. 0.7 v
58. Which of the following is an active element of a circuit?
A. Ideal current source
B. Resistance
C. Inductance
D. Capacitive
59. A 200 µH coil has a Q of 250 at resonance frequency of 800 KHZ.
What is the effective resistance of the coil?
A. 1 Ω
B 2Ω
4Ω
D 8Ω
SOLUTION:
800 x 103 = 1 / 2 pi (sqrt. (200 x 10 -6 (C))
C = 1.98 x 10-10 F
250 = (1 / R) (sqrt.(200 x 10-6 /1.98 x 10-10)
R=4 2Ω
60. Find the capacitive susceptance per mile of a single-phase line
operating at 60 HZ. The conductor is Partridge with an outside
diameter of 0.642 in, and spacing is 20 ff between centers.
A. 5.10 x 10-4 mho/mi to neutral
B. 0.1961 x 104 mho/mi to neutral
C.5.10 x10-6 mho/mi to neutral
D.0.1961x 10-4 mho/mi to neutral
61. Which wqave form will have the minimum rms value if they have the
same peak value of voltage?
A. Square wave
B. Sine wave
C. Triangular Wave
D. Full wave rectified sine wave
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
62. The line currents in amperes in phases a, b and c respectively are 500
+ j150, 100 – j600, and -300 + j600. Determine the zero sequence
component of phase a current
A. -100 – j50 amps
C. 100 – j50 amps
B. -100 + j50 amps
D. 100 + j50 amps
SOLUTION:
Iao =1/3 (Ia+Ib+Ic)
Iao =1/3 { (500+j150) + (100-j600) + (-300+j600) }
Answer: 100 + j50 amps
63. The minimum armature current of a synchronous motor corresponds to
operation at
A. 0.8 p.f. lagging
B. unity p.f.
B. C. 0 p.f. leading
D. 0 p.f. lagging
64. A 10 KW, 110 volts dc series generator has a 2 volts brush drops, an
armature resistance Ra of 0 1 Ω and a series field resistance Rs of 0.05
Ω Calculate the generated emf when delivering rated current at rated
speed.
A. 110 v
B. 130.25 v
C. 115.56 v
D. 125.64 v
SOLUTION:
Eg = Vt + Ia(Ra+Rs) + Vb
Eg = 110 + (10X10^3/110)(0.1 + 0.05) +2
Eg = 125.64 V
65. Lap winding is best siuited for
voltage,
current
dc
C. High, High
D. Low, Low
generators.
A. High, Low
B. Low, High
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
66. A three-phase motor is rated 50 HP, 440 volts and 85% power factor.
What is the rated current if the motor efficiency is 89%?
A. 57.5 A
B. 64.7 A
C. 55 A
D. 59 A
SOLUTION:
P = squareroot of 3 x V x I x pf
(50 x 746)/0.89 = squareroot of 3 (440)(I)(0.85)
I = 64.7 A
67. The phase b line voltage and the phase a line current of a balanced
three phase system are V = 220 sin ωt
210º and I = 10 sin ωt - 30º)
respectively. What is the power of the system?
A. 1,905 W
B. 5,716 W
C. 3,300 W
D. 3,810 W
SOLUTION:
Z = 220 sin ωt
210º / 10 sin ωt 180º
Z = 22 cis 30
P = squareroot of 3 (220)(10)cos30
P = 3,300 W
68. A 200:5 current transformer is used with a 10 amps ammeter. If the
meter reads 4.5 amps, determine the line current.
A. 400 A
B. 20 A
C. 45 A
D. 180 A
SOLUTION:
I = I ratio X I reading
I = (200/5)(4.5)
I = 180 A
69. What is the relative permittivity of vacuum?
A. Unity
B. 8.854 x 10-12
C. 8.854
D. zero
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
70. On triling the number of turns of a coil the inductance
A. Becomes 9 times as large
B. 3 times
C.1/3
C Will remain the same
71. A 1 5 MΩ resistor is connected in series with a 20 µF capacitor. The
voltage source is 120 volts dc. Determine the current at t = 10 seconds
after switch is closed.
A. 80 µA
B. 63.85 µA
C. 32,64 µA
D. 57.32 µA
SOLUTION:
T=RC=20micro x 1.5mega=30 sec
Q=CV=20micro(120)=2.4x10^-3 F
q=Q(1-e^(-t/RC))=2.4x10^-3(1-e^(-10/30))
q=6.803x10^4 F
q=cv; v=q/c= 6.803x10^-4 F/20micro
v=34.016; voltage resistor is equal 120-34.016
voltage resistor = 85.984; i=v/r
i=85.984/1.5 mega= 57.323 micro ampere
72. A dc ammeter has an internal resistance of 0.1 ohm. A shunt of 1.01 x
10-3 ohm is connected to the ammeter. What is the multiplier of the set
up?
A. 80
B. 50
SOLUTION:
Multiplier: (Rg+Rsh)/Rsh
= (0.1+0.00101)/0.00101
C. 100
D. 10
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
=100
73. The field circuit of a 200 KW, 230 volts shunt generator is 8 A when
running full-load at rated terminal voltage. If the combined brush and
armature resistance is 0 03 Ω, solve for the electrical efficiency of the
generator.
A. 88.9%
B. 85.7%
C. 93.5%
D. 81.7%
SOLUTION:
IL=PL/VL=200000/230=869.56 A
Ia=IL+ISH=877.56
E=VL+IaRa=230+877.56(0.03)=256.32V
Pg=EIa=256.32(877.56)=224.936 KW
n=PL/Pg x 100 = 88.91%
74. A parking lot is to be illuminated by four floodlights placed on each
corner of the lot mounted on 7 meters high poles. The parking lot
measures 25 m x 20 m. if each lamp has an output of 500 candelas,
calculate the illumination at the center of the lot.
A. 51.44 lux
B. 25.72 lux
SOLUTION:
d2=12.52+102+72
d2=305.25
Ep=(I/d2)cos theta
Ep=(500/305.25)(7/17.471)
Ep=25.62 lux
C. 6.43 lux
D. 12.86 lux
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
75. An external resistance is added in series with the field of a dc shunt
motor. When the motor runs, the effect of resistance is
A. To reduce the speed of the motor
B. To increase the speed of the motor
C. To reduce the armature current drawn by the motor
D. To reduce the losses
76. The PTs of a 220 KV transmission line have a ratio of 132.76 KV/
66.375 v and are connected wye-wye. A voltmeter connected line to
ground reads 66 volts, what is the transmission line voltage?
A. 228.65 KV
B. 220.10 KV
C. 223.15 KV
D. 225.25 KV
SOLUTION:
VL=V x PT ratio
=114.316(132.76 KV/66.375)
=228.65 KV A
77. What is the speed of an induction motor of four poles if the percent slip
is 3%?
A. 1,764 rpm
B. 1,756 rpm
C. 1,746 rpm
D. 1,730 rpm
SOLUTION:
f=PN/120; N=120f/P=(120 x 60)/4
N=1800 rpm
Ns=1800(0.03)=54
N-Ns=756 rpm
78. A 3 phase synchronous motor runs at full load of 1,200 rpm. If the load
is reduced to one-half of rated, calculate its speed regulation.
A. 100%
SOLUTION:
B. 50%
C. 0%
D. 86.6%
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SR%=(NR-NS)/NS
NR=1200 rpm
NS=f(120)/P=60(120)/3
NS=2400/2=1200
SR%=(1200-1200)/1200=0
79. Whicj of the following is not the method of arc dispersion?
A. Oil immersion contacts
B. Magnetic blow out of
arc
C. Use of rectifiers
D. Deionization of arc path
80. During load shedding
A. System voltage is reduced
B. Some loads are switch off
C. System power factor is changed D. System frequency is reduced
81. The capacitor in a series RC circuit at steady state is:
A. Open circuit
B. Short circuit
C. Transient circuit
D. Coupled circuit
82. A lead storage battery is rated at 12 volts. If the internal resistance is
0 01 Ω, what is the maximum power that can be delivered to the load?
A. 1,200 watts
B. 7,200 watts
B. C. 1,800 watts
D.3,600watts
SOLUTION:
P = 122 / 4(0.01) = 3600 watts
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
83. Two No. 8 copper conductors are placed 15 cm apart with a GMR of
1.27 x 10-3 m. if the lenth of the line is 4 km, find the value of the line
inductance.
A. 9.65 mH
B. 6.85 mH
C. 5.78 mH
D. 7.63 mH
SOLUTION:
d= 15cm×
L= 4
-7
=0.15m
ln(
=4× 10-7 ln(
)
)
L=1.9086×10-6
@4 km
4km×
L= 1.9086×10-6 ⁄ ×4000m
L= 7.63 mH
84. There is no zero sequence component of the fault current for
A. Line to line fault
B. Single line to ground fault
C. Symmetrical fault
D. Double line to ground fault
85. A diesel generator set burns fuel with a heating value of 18,000 BTU
per lb. the diesel engine has an efficiency of 30% and the alternator
has an efficiency of 95%. Determine the fuel cost component of
producing one KWHR if the diesel costs P 2.80 per lb
A. P 0.15
SOLUTION:
B. P 2.15
C. P 3.28
D. P 1.86
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Let ɳeng=efficiency of the diesel engine
ɳalt=efficiency of the alternator
Win=
(
)(
)
Lbs.of coal=
= 0.66548 lbs.
Fuel cost = 0.66548 lbs. × (2.80) = 1.8633
Fuel cost = 1.86
86. The ratio of lumens reaching the work plane divided by the total
lumens generated by the light is:
A. Room ratio
B. Coefficient of utilization
C. Illumination factor
D. Maintenance factor
87. A 50 Ω resistance is connected in series with a coil having 25 Ω
resistance and 150 mH inductance. The circuit is connected to a
voltage source of 200 sinωt Calculate the instantaneous current
A. 2 9 sinωt
B 2
C 1 7 sin ωt-37º)
D 5 11 sin ωt-37º)
SOLUTION:
Square root (2) x 200 = 163.30
Square root (3)
200-163.30=37
200
= 2.1
25+j150
2
sin ωt-37)
88. What is 1013 ergs/sec in KW?
sin ωt-37º)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 1,000 KW
B. 2,000 KW
C. 1,800 KW
D. 3,000 KW
SOLUTION:
1kW=1000W, 1 Watt= 1
, ergs= 10-7
1013ergs/sec×10-7 joule=1×106
1
=1000 kW
89. Find the rotor frequency of an induction motor having 4 poles if the
rotor speed is 1,746 rpm.
A. 60 HZ
B. 1.8 HZ
C. 3 HZ
D. 50 HZ
SOLUTION:
Ns=
=
S=
=
(
)
=1800 rpm
=0.03
Fr=sf= 0.03(60)
=1.8Hz
90. The conductors of a 30 km long transmission line have a triangular
configuration. The conductors are placed 4 ft apart. Each conductor
has 336.4 MCM ACSR and its diameter is 0.75 inch. Find the
capacitive reactance per phase?
A. 5,389 Ω/phase
B 1,354 Ω/phase
7,7 2 Ω/ph s
D. 8,261 Ω/phase
SOLUTION:
Deq= √( )( )( ) = 4
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
C=
(∑ )
( )
=
Xc=
(
(
(
)
= 11.4604
=231.456×106
)(
=231.456×106m×106
=
231.456×103km
= 7715.2
=7715.2 Ω / phase
91. The secondary current of a 20 KV/7.79 KV autotransformer is 100
amperes. Determine the current that flows through the common
winding.
A. 60 amps
B. 100 amps
C. 79 amps
D. 50 amps
SOLUTION:
therefore, for step down autotransformer:
Ic=100-38.5
Ic=60 A
92. A winding is short pitched by 60 degrees electrical. Its pitch factor is:
A. 0.5
B. 0.707
C. 0.966
D. 0.866
SOLUTION:
Sin (60) = 0.866
93. When the excitation of an unloaded salient pole synchronous motor
suddenly gets disconnected, then
A. The motor stops
B. It runs at the same speed
C. It runs at lower speed
D. It runs at very high speed
94. Sensitivity of a voltmeter is expressed as
A. Volts/Ohm
B. Ohms/Volt
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
B. C. Ohm-Volt
D.1/Ohm-Volt
95. Two conductors carrying 50 amperes and 75 amperes respectively are
placed 10 cm apart. Calculate the force between them per meter.
A. 0.075 N/m
B. 100 N/m
C. 0.0075 N/m
D. 10 N/m
SOLUTION:
(
)(
)(
)
F=0.0075 N/M
96. A coil has a resistance of 3 Ω and an inductance of 0 01 H is
connected in series with a capacitor across a voltage source of 220
volts. What must be the capacitance of the capacitor in order that
maximum current occurs at 60 HZ?
A. 3.77 µF
B. 703.6 µF
C. 0.03 µF
D. 512.45 µF
SOLUTION:
60 = 1 / 2 pi (sqrt (0.01 (C))
C = 703.62 µF
97. In a T-T connected transformer, if the terminal voltage in the primary
side is 220 volts, what is the voltage across the teaser transformer?
A. 127 volts
B. 190 volts
C. 220 volts
D. 110 volts
SOLUTION:
220(.866)= 190 V
Note that the in T-T bank primary is 50% and the teaser is 86.6%
98. At a certain point of the system network the positive, negative and zero
sequence impedances are 0.25 pu, 0.25 pu, 0.3 pu, respectively. The
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
base MVA is 100. The level at that point is 34.5 KV. Determine the
zero sequence current for a one line to ground fault.
A. 6,275 A
B. 7,516 A
C. 8,132 A
D. 2,091A
SOLUTION:
Ifpu = 3 (1 / 0.25 + 0.25 + 0.3) = 3.57 pu
If = 3.75 ( 100 x 106 / 34.5 x 103 (sqrt (3))) = 6275.55 A
99. The dc armature winding in which the coil sides are placed a pole pitch
apart is called
winding.
A. Multiplex
B. Full-pitch
100.
C. Fractional-pitch D. Pole-pitch
A power plant gets water from a dam from a height of 100 m at the
rate of 1,000 cubic meters per minute. If the overall efficiency of the
plant is 75%, what is the KW output of the plant?
A. 12,250 KW
B. 5,250 KW
C. 7,550 KW
D. 15,250 KW
SOLUTION:
(
)(
)(
)
AUGUST 2015
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1. One kwhr is equal to_____ BTU.
A. 960
B. 3,413
C. 3600
D. 1000
2. Which of the following is the basis of standards of electrical wiring installation
in the Philippines?
A. Philippine Distribution Code
C. Philippine Electrical Code
B. Philippine Grid Code
D. Fire Code of the Philippines
3. In dwelling units with a hallway of 3m or more in length, at least how many
receptacle outlet/s shall be installed?
A. 3
B. 2
C. 1
D. none
4. When installing two grounding electrodes, the minimum distance between
them is
A. 1800 mm
B. 2000 mm
C. 1500 mm
D. 2400 mm
5. A lamp produces an initial illumination of 800 lux over a normally placed
screen. If the distance of the lamp from the screen is doubled, what is the
new illumination on the screen?
A. 100 lux
B. 200 lux
C. 300 lux
D. 400 lux
6. What is the minimum required ampacity of the feeder conductors supplying a
5A, single-phase motor and a 10A lighting load?
A. 14.25A
B. 15.5A
C. 17.5A
D. 16.25A
7. When the length of a wire is doubled and all other factors remained the same,
what would the wire resistance become?
A. Remained the same
C. decreased
B. Doubled
D. could not be determined
8. A 3 phase, 60Hz, 60-pole induction motor delivers 25 HP at 1,150rpm. If the
rotor copper loss is 300 watts, what is the rotor power input?
A. 7,194 w
B. 6,194 w
C. 8,194 w
D. 5,194 w
9. An aluminum wire has a diameter of 2 mm. What must be the diameter of
copper wire of the same resistance and length as aluminum?
A. 1.33 mm
B. 1.45 mm
C. 1.56 mm
D. 1.75mm
10. A customer owns an old air conditioning unit rated ½ HP at 70% efficiency but
decide to buy a new one of the same horse power rating with 85% efficiency
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
and with 2 years warranty. If the usage of new unit is 8 hours per day and 150
days per year, what is the differential cost of energy in one year when the unit
cost of energy is P8.99/KWHR?
A. P9,870
B. P8,070
C. P1,014
D. P2,029
11. Three impedances Z1= 2.2+j2.2 , Z2= 10+j10 and Z3=-j5 are connected in
series. The voltage across Z1 is 26. 59-j4.69 v. What is the total voltage?
A. P93+j62.4 v B. 93-j62.4 v
C. 112+j51 v
D. 112-j51 v
12. A series circuit consists of three resistors R1, R2 and R3 which are connected
to a 240 v source. If the voltage drop across R1 is 60 v when the current is 4
A and R2= 1.5 R3, what is the ohmic resistance R3?
A. 15
B. 18
C. 27
D. 28
13. Two exactly similar turbo-alternators are rated 5 MW each. They are running
in parallel. The speed load characteristics of the driving turbines are such that
the frequency of alternator one drops uniformly from 60 Hz on no-load to
57.5Hz on full-load, that of alternator two from 60 Hz to 58 Hz. How will two
machines share a load of 8,000 kW?
A. 3,556 kW, 4,444 kW
C. 3,500 kW, 4500 kW
B. 4,000 kW, 4,000 kW
D. 3,636 kW, 4,364 kW
14. Two coupled coils have self-inductances L1= 2 H and L2= 0.5 H, and a
coefficient of coupling k= 0.9. Determine the turns N1/N2 of the two coils.
A. 2
B. 0.2
C. 0.5
D. 0.9
15. A 220-v bulb draws a current of 10 A. How much change in kilocoulombs will
pass through the bulb in two hours period?
A. 7.2
B. 3.6
C. 36
D. 72
16. A 36
resistor is connected in parallel with an unknown resistor R. Their
combination is then connected in series with a 12 resistor. Find the value of
R such that power drawn by the parallel combination of 36 and R is equal to
the power in the 12 resistor.
A. 48
B. 24
C. 18
D. 6
17. A 3 phase, 60 Hz transposed transmission line is arranged horizontally with
distances D12= 5 ft., D23= 5 ft. and D13= 10 ft. The outside diameter of the
conductors is 0.721 inch and with GMR of 0.0243 ft. determines the
capacitance per phase of the line in microfarad per kilometer.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 0.0404
B. 0.0304
C. 0.0204
D. 0.0104
18. An act to ensure and accelerate the total electrification of the Philippines, also
known as the EPIRA law of 2001.
A. RA 7920
B. RA 8189
C. RA 9136
D. RA 1081
19. Which of the following is not included in the evaluation of the Technical
Performance of a Distribution System according to Philippine Distribution
Code (PDC)?
A. Power quality
C. Collecting Efficiency
B. Reliability
D. System Efficiency
20. A 13.8 kV/480 v, 30-MVA three- phase transformer has a 0.03 pu resistance
and 0.004 pu reactance. What is the transformer actual impedance referred to
the primary?
A. 0.3174
B. 0.6348
C. 0.1587
D. 0.2749
21. Three capacitance of 4µF, 6 µF, and 5 µF are connected in series across a
110-volt dc source. Find the charge passing through each capacitor.
A. 1,650 µC
B. 69 µC
C. 178 µC
D. 7.33 µC
22. 7.1x10^10 BTU is equal to______ Gcal.
A. 17.829
B. 178.92
C. 1,789.2
D.17,892
23. Calculate the force that will be exerted on the scale in pony-brake test when a
20-HP, 1,400 rpm motor is operating at full-load. The length of the brake arm
is 3-ft, and the tare weight of the brake is 3.75lb.
A. 26.86 lb
B. 62.76 lb
C. 36.70 lb
D. 28.76 lb
24. The core of a certain magnetic circuit has a length of 5 cm and the inductance
of the coil is 10 mH. What is the inductance of the same if the number of turns
is reduced to 1/2 of the original? All other factors are unchanged.
A. 20 mH
B. 10 mH
C. 2.5 mH
D. 5.0 mH
25. A piece of conductor 20 cm long moves across a magnetic field of 10,000
gauss at a velocity of 120 cm/sec. What voltage appears across the
conductor?
A. 0.24 v
B. 0.12 v
C. 120 v
D. 60 v
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
26. A certain electric generating station has an efficiency of 25%. If coal
consumption is 4,500 kg/hr and calorific value of coal is 6,000kcal/kg. Find
the total energy produced per day.
A. 753.6 MWHR
B. 188.4 MWHR
C. 376.8 MWHR
D.565.2 MHWR
27. Three 40 non-inductive resistances are connected in wye across 200 v, 3phase lines. If one of the resistors is disconnected, what would be the power
taken from the mains?
A. 3,000 w
B. 2,000 w
C. 1,000 w
D. 500 w
28. A 220 v, 3-phase supply has a balanced delta connected load with
impedance of 15+j20 /phase. What is the total real power of the load in
watts?
A. 5,133.3
B. 2,965.6
C. 4,122.5
D. 3,484.8
29. Sparking occurs when a load is switched off because the circuit has high
A. Capacitance B. inductance
C. resistance
D. impedance
30. A 120-volt battery having an internal resistance of 0.5 is connected through
line resistance of 9.5 to a variable load resistor. What maximum power will
the battery deliver to load resistor?
A. 36 watts
B. 63 watts
C. 630 watts
D. 360 watts
31. A sis pole induction motor is connected to a 60 Hz supply and full-load the
rotor emf makes 105 complete cycles in 2 minutes. Find the rotor speed.
A. 1,150 rpm
B. 1,182.5 rpm
C. 1,140.5 rpm
D. 1,170 rpm
32. A. 20 kVA, 2000/220 v, single –phase transformer has a primary resistance of
2.1
and a secondary resistance of 0.026 . The corresponding leakage
reactances are 2.5
and 0.03 . Determine the transformer per unit
impedance.
A. 0.065 pu
B. 0.043 pu
C. 0.033 pu
D. 0.055 pu
33. Slip ring are made of
A. Steel
B. copper
C. bakelite
D. mica
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
34. The resistance of a coil of wire increases from 40 at 10 degrees Celsius to
48.25 at 60 degrees Celsius. Find the temperature coefficient at 0 degrees
Celsius of the conductor material.
A. 0.0043 C-1 B. 0.0039 C-1
C. 0.0027 C-1
D. 0.0013 C-1
35. The primary reason for using carbon brushes over copper brushes in DC
motors is
A. They have low loss
C. They produce less arcing
B. They are stronger
D. all of these
36. A capacitor consists of two metal plates each plates 40 cm x 40 cm, spaced
6 mm apart. The space between the metal plates is filled with a glass plate
5mm thick and layer of paper 1mm thick. The relative permittivities of glass
and paper are 8 and 2, respectively. Calculate the capacitance.
A. 118 X 10-11 F B. 122X10-11 F
C. 126X10-11 F
D.130X10-11 F
37. A single-phase transformer is rated 110/440 v, 2.5 kVA. Leakage reactance
measured from the low- tension, side is 0.06 . Determine leakage reactance
on the high-tension side in per unit.
A. 0.0124
B. 0.1984
C. 0.0496
D.0.3963
38. The capacitance per kilometer of a 3-phase belted cable is 0.3µF between the
two cores with the third core connected to the lead sheath. Calculate the
charging current taken by the five kilometers of this cable when connected to
a 3-phase 50 Hz, 11kV supply.
A. 5.98A
B. 10.37A
C. 3A
D. 4.18A
39. Power developed by dc motor is maximum when the ration of back emf and
applied voltage is
A. Double
B. Zero
C. Unity
D. Half
40. An office 15m by 8m wide is lighted by 8 lamps and each lamp has luminous
intensity of 200 sd, allowing an absorption loss of 4,000 lm for the reflectors,
walls, and ceiling, calculate the average illumination on the working plane.
A. 167.6 lux
B. 134.2 lux
C. 20.9 lux
D. 106.7 lux
41. Two coils having inductances of 20 mH and 50 mH are wound on top of each
other. Calculate the mutual inductive between the two coils if the coupling
coefficient k= 0.98
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 29 mH
B. 30 mH
C. 31 mH
D. 32 mH
42. A lead storage battery is rated at volts. If the internal resistance is 0.01
what is the maximum power that can be delivered to the load?
A. 1,200 watts B. 7,200 watts
C. 3,600 watts
D. 1,800 watts
,
43. Two charges of 2 x 10-5 C and 3 x 10-6 C are placed 10cm apart. Find the
force in kg on each charge.
A. 5.5kg
B. 7.7kg
C. 10kg
D. 2.25kg
44. Three units of 1:10 Transformers are connected in ∆/Y to supply a 3-phase
load from a 400-v, 3-phase source. What is the line voltage on the load side?
A. 6,928 v
B. 3,464 v
C. √3(40)v
D. 4,000 v
45. The starting winding of single-phase motor is placed in
A. Rotor
B. stator
C. armature
D. field
46. A 50-MVA. 11-kV, 3-phase alternator supplies full-load at a lagging power
factor of 0.7. What would be the percentage increase in earning capacity if
the power factor is increase in earning capacity if the power factor is
increased to 0.95?
A. 26.32
B. 6.92
C. 12.76
D. 35.71
47. In a synchronous motor, the rotor copper losses are met by
A. Motor input
B. armature input
C. supply lines
D. DC source
48. A string insulator has 5 units. The voltage across the bottom most unit is 25%
of the total voltage. What is the string efficiency?
A. 80%
B. 75%
C. 67%
D. 86%
49. A delta connected load of 9 +j12 /phase is supplied by a 230 v, 3-phase
source through a line with an impedance of 0.06+j0.12 /conductor. Find the
load voltage in volts.
A. 220
B. 222
C. 224
D. 226
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
50. A substance that contains atoms with several bands of electrons but with only
one valence electron is
A. Insulator
B. Conductor
C. Semiconductor D. Resistor
51. What is the resistance of 2,000 m of copper wire that has a resistivity of 1.72X
10-8 -m and a diameter of 4-mm?
A. 0.086
B. 2.74
C. 1.37
D. 3,24
52. The charge on the plates of a 1µF capacitor is 50 µC. What is the energy
stored by the capacitor?
A. 1.25 mJ
B. 25mJ
C. 5.5mJ
D. 10.5Mj
53. What is the ac current in a circuit if the impedance is 5 j4 Ω and the voltage
source, Vrms is 10v?
A. 2.04 38.7 A B. 1.56 -38.7 A C. 1.25 54.3 A
D. 1.11 -42.6 A
54. If the capacitance in a series RLC ac circuit increase by a factor of 4, what
happens to the resonant frequency?
A. It doubles
C. It decrease by 50%
B. It stays the same
D. It increases by 50%
55. A 10:1 ideal transformer has a load of 0.1µF on the secondary. What is the
load capacitance, as referred to the primary?
A. 1µF
B. 10µF
C. 0.01µF
D. 0.001µF
56. A 110-volt shunt motor has an armature resistance of 0 8Ω and a field
resistance of 220Ω At full load the motor takes 10 amperes, and the speed is
1,200 rpm. At what speed must this motor run as a generator to deliver 10
amperes to an external circuit at 110v?
A. 1,237.8 rpm B. 1,337.5 rpm
C. 1,037.8 rpm
D. 1,387.5 rpm
57. When a conductor is stationary and the magnetic field is moving or changing,
the emf is called:
A. Self-induced emf
C. Mutually induced emf
B. Statically induced emf
D. Dynamically induced emf
58. The per unit impedance of a circuit element is 0.30. If the base kV and base
MVA are halved, then the new value of the per unit impedance of the circuit
element will be
A. 0.30
B. 0.003
C. 0.60
D. 0.006
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
59. In a series RL circuit, R=20Ω and L= 0 06H The current lags the voltage by
80. Determine .
A. 1,890 rad/sec
B. 328 rad/sec
C. 1,980 rad/sec
D. 823 rad/sec
60. A 12-pole, 3- phase alternator driven at a speed of 500 rpm supplies power to
an 8-pole, 3-phase induction motor. If the slip of the motor at full-load is 3%,
calculate the full-load speed of the motor.
A. 750 rpm
B. 734.5 rpm
C. 727.5 rpm
D. 742 rpm
61. A coulomb
A. Represent a current of 1 ampere
B. Flows through a 100-watt light bulb
C. Is equivalent to 1 ampere per second
D. is an extremely large number of charge carriers
62. A balanced wye-connected load with resistance of 8 Ω/phase and no
reactance is supplied by a 240v, 3-phase source. Find the real power of the
load in watts.
A. 6,400
B. 7,200
C. 6,800
D. 7,600
63. Given three unbalanced line currents Ia= 0+j12 A, Ib=5-j10A and Ic=-10-j5A.
Find the negative sequence component of Ic in amperes.
A. 3.12 -14.3 B. 3.12 14.3
C. 2.25 -14.3
D. 2.25 14.3
64. A hollow sphere is charged to 12 µC of electricity. Find the potential inside the
sphere. The radius of the sphere is 0.1m.
A. 1.08x107v
B. 1.08x106v
C. 1.08x104v
D. 1.08x 102v
65. An electromagnet has an air gap of 3 mm and the flux density in the gap is
1.257 Wb/m2. Calculate the ampere-turns required for the gap.
A. 2000
B. 2,500
C. 3,000
D. 4,000
66. An alternating current is represented by i=70.7sin 520t. Determine the value
of the current 0.0015 second after passing through zero and increasing
positively.
A. 49.7 A
B. 0.96 A
C. 24.8 A
D. 74.9 A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
67. A 50-kVA single-phase transformer has on full-load a copper loss of 560
watts and iron loss of 500 watts. Calculate the efficiency at 25% of full-load
for a power factor of 0.8 lagging.
A. 92.94%
B. 94.92%
C. 93.94%
D. 95.92%
68. Fault level means
A. Voltage ate the point of fault
C. Fault power factor
B. Fault current
D. Fault MV
69. Which plant can never have 100% load factor?
A. Hydro
B. Peak
C. Nuclear
D. Base load plant
70. A lamp produces an illumination of 10 lux at point 10 m directly below it. What
is luminous intensity of the lamp?
A. 100
B. 1000
C. 10
D. 1
71. Find the capacitive susceptance per mile to neutral of a single-phase line
operating at 60 Hz. The conductor is Partidge with an outside diameter of
0.642 inch, and spacing is 20ft between centers.
A. 2.55x10^-6 mho/mi to neutral
C. 5.10x10^-6 mho/mi to neutral
B. 2.55x10^-4 mho/mi to neutral
D. 5.10x10^-4 mho/mi to neutral
72. A 100 mw power station delivers 100 MW for 2hrs, 50 MW for 8hrs and is
shut down for the rest of each day. It is also shut down for maintenance for 60
days each year. Calculate its annual load factor.
A. 18%
B. 19%
C. 20%
D. 21%
73. When a line to ground fault occurs, the current in a faulted phase is 300 A.
What is the zero sequence current in this case?
A. Zero
B. 100A
C. 200A
D. 300A
74. Two 100-watt lamps connected in series across a 220-v line draw 1 A. What
is the total power consumed?
A. 200w
B.220w
C. 100w
D. 50w
75. Three capacitors connected in series across a 135-v supply. The voltage
across them are 30,45 and 60v and charge on each is 4,500 µC. Find the
total capacitance in microfarads.
A. 33.3
B. 100
C. 75
D. 150
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
76. A potential lethal electric current is on the order of
A. 0.01 mA
B. 0.1mA
C. 1mA
77. The unit elastance is
A. Farad
B. daraf
C. siemen
D. 0.1A
D. henry
78. A complex current wave is represented by the equation i= 5+ 5sin(120pi)t A.
Find its average value in amperes.
A. 4.5
B. 6
C. 5
D. 4
79. The core loss of a 5-kVA single-phase transformer with normal voltage
applied to the primary is 75 watts. The maximum efficiency occurs 60% of fullload kVA. What is the full-load efficiency of the transformer at 0.80 power
factor?
A. 95.16%
B. 93.38%
C. 89.52%
D. 91.36%
80. A 34.5 kV feeder line is 5 miles long. The conductors are spaced 4-feet
horizontally. The conductor is 4/0 copper with GMR of 0.01688 ft. What is the
reactance?
A. 2.36 Ω
B. 6.72 Ω
C. 3.46 Ω
D. 5.16 Ω
81. A power plant gets water from a dam from a height of 122.45 meters at the
rate of 1,000 cubic meters per minute. If the output of the plant is 15,000kW,
what is the plant efficiency?
A. 65%
B. 70%
C. 75%
D. 80%
82. If resonant frequency is 10kHz and quality factor is 50, then
A. Bandwidth is 200 Hz
C. R= 50 Ω
B. XL=50,000 Ω
D. Xc= 50,000 Ω
83. All magnetic fields originates from
A. Moving electric charges
B. Iron atoms
C. magnetic domain
D. permanent magnets
84. A capacitor is charged by a dc source through a resistor of one megohm. If in
one second, the potential difference across capacitor reaches 80% of its final
value, calculate its capacitance.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 0.321µF
B. 0.421µF
C. 0.512µF
D. 0.621µF
85. The input power to a 3-phase induction motor running without load is
measured by two wattmeter method. One wattmeter indicates-220 watts and
the other one indicates 940 watts. What is the no –load power factor of the
motor?
A. 0.483
B. 0.253
C. 0.425
D. 0.337
86. The power required to produce a gain of 10dB over 4 w of original power is
A. 80w
B. 40w
C. 0.4w
D. 8w
87. In a 12-Pole duplex lap wound dc armature, each conductor can carry a
current of 50 amperes. If the total armature conductor is 600, what is the
rated current of the armature?
A. 30,000A
B. 1,200A
C. 600A
D. 2,500A
88. A 5-MVA, 13.8 kV/480 V, 5% impedance transformer is tapped at 13.8 kV line
where the Thevenin’s equivalent impedance is 0 5Ω Determine the fault
current at the primary for a three-phase fault at the secondary.
A. 10,500A
B. 4,200A
C. 6,050
D. 3,300A
89. If stator voltage of a SCIM is reduced to80% of its rated value, torque
developed is reduced by____ percent of its full-load value.
A. 64
B. 36
C. 20
D. 40
90. An ion
A. Is electrically neutral
B. Has positive electric charge
C. has negative electric charge
D. can have either a positive or negative charge
91. Two long straight conductors each carrying an electric current of 5A are kept
parallel to each other at a separation of 2.5cm. Calculate the magnitude of
magnetic force experienced by 10cm of a conductor.
A. 5X10^-5N
B. 4x 10^-5N
C. 3x 10^-5N
D. 2x 10^-N
92. The current in the coil of a large electromagnet falls from 6A to 2A in 10ms.
The induced emf across the coil is 100v. What is the self- inductance of the
coil?
A. 10H
B. 5H
C. 0.50H
D. 0.25H
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
93. An induction motor is analogous to
A. Two winding transformer with open circuit secondary
B. Two winding transformer with short circuit secondary
C. 3 winding transformer
D. Autotransformer
94. A three-phase,4-pole,50 Hz induction motor supplies a useful torque of 160
N-m at 4% slip. If friction and windage losses are 500 watts, determine the
rotor input.
A. 25,653w
B. 26,653w
C. 24,615w
D. 23,615w
95. In a balanced 3-phase voltage source with phase sequence abc, phase A
voltage is 127cis 0 volts. Find the line voltage Vbc
A. 220 cis(-150)v
B. 220 cis(-120)v C. 220 cis(-60)v
D. 127 cis(-120)v
96. If the line frequency is 60 Hz, the output frequency of a bridge rectifier is
A. 30 Hz
B. 60 Hz
C. 120 Hz
D. 240 Hz
97. A diesel generator set burns fuel with a heating value of 18,000 BTU per lb.
The diesel engine has an efficiency of 30% and the alternator has an
efficiency of 95%. Determine the fuel cost component of producing one
KWHR if the diesel cost P12.80 per lb.
A. P8.51
B. P7.51
C. P6.51
D. P5.51
98. The capacitance reactance of a transmission line is 90,000 ohms per
kilometer. Find the total capacitive reactance of a transmission line is 60-km
long.
A. 5.4x10^6 ohms
B. 1500 ohms
C. 90,000 ohms
D. 180,000 ohms
99. Estimate the distance over which a load of 150 MW at a power factor of 0.8
lagging can be delivered by a three phase transmission line having a
conductors each of the resistance 1 ohm per kilometer. The voltage at the
receiving end is to be 132 kV and the loss in the transmission is to be 5% of
the power delivered.
A. 37.18 km
B. 55.77 km
C. 42.93 km
D. 74.36 km
100. A power transformer rated 50MVA, 34.5kV/13.8 kV is connected wye-wye.
What is the rated primary line current?
A. 636.7 A
B. 1,449.3A
C. 2,091.8
D. 1,207.7A
SOLUTION:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1.
2.
3.
4.
5.
1Kwhr = 3413 BTU
C. Philippine Electrical Code
C. Outlet
A. 1800 mm
B. 200 Lux
Solution :
(
*
(
6. D. 16.25
Solution:
(
)( )
7. B. doubled
Solution:
8. A. 7, 194 W
Solution:
(
9. C. 156 mm
Solution:
(
10.
)
( )
)(
)
*
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
11. D. 112-j51 V
Solution :
(
((
12. B. 18
Solution :
13. A. 3556 kW, 4.444kW
Solution :
@58Hz
@57.5Hz
14. A. 2
Solution ;
)
)
(
)
(
))
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
√
15. D. 72
Solution:
(
)(
)( )
𝐶
16. C 18Ω
Solution :
17.
18.
19.
20.
21.
C. RA 9136
C. Collecting Efficiency
A 0 3174Ω
C. 178µC
Solution:
𝐶
𝐶
((
)
(
)
(
) )
𝐶
(
)(
𝐶
)
22. D. 17.89
Solution:
23. D. 28.76
Solution:
(
)(
(
)
)( )
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
24. C. 2.5 mH
Solution ;
(
(
*
)(
)(
*
25. B. 0.12 v
Solution :
(
)(
)
26.
27. D. 500 w
Solution ;
28. D. 3.48
Solution :
220/15+j20= 5.28+j 7.04
(
)(
)
29. B. Inductance
30. D. 360 watts
(
)
31. B. 1 182.5
Solution :
(
)
(
32.
)(
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
33. B. Copper
34. A. 0.0043⁰C
𝐶
35. C. They Producing less arching
36.
37. A. 0.0124
Solution:
(
)(
*
38. A. 5.98 A
(
(
)( )
)(
(
)(
)
)
39. D. half
40.
41. C. 31mH
Solution:
)(
√(
√
)
42. C. 3600 watts
Solution:
(
)
43. A. 5.5 kg
Solution :
(
)(
(
)
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
44. A. 400:4000
Solution:
√ (
)
45. B. Stator
46. D.35.71
Solution :
47. D. DC Source
48. A. 80 %
Solution:
49.
50. B. Conductor
51. B 2 74Ω
Solution :
(
)(
(
)
)
52. A. 1.25 mJ
Solution :
𝐶
W= 1.25 mJ
53. B. 1.56 -38.7 A
Solution :
54. C. It decreases by 50 %
55. D. 0.001 F
Solution :
(
)(
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
(
𝐶
𝐶
(
)(
)
)(
*
001µF
56. D. 1387.5 rpm
Solution :
(
(
)
)( )
(
) )
(
)(
)
57. B. Statically induced emf
58.
59. A. 1890 rad/sec
Solution :
( )(
)
60. C. 727.5
Solution :
(
)(
)
@motor
(
(
)
)(
)
(
)(
61. D. is an extremely large number of charge carriers
62. B. 7200
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
( √
(
,
√ )(
√
√
*
63. C. 2.25 -14.3
Solution :
(
)
((
(
)
)(
)
(
)(
64. B. 1.08 x10^6 V
Solution :
(
)
65. C. 3000
(
)(
)
= 3,000
66.
67. B. 94.92
Solution :
(
)(
(
(
)
) (
)
68. D. Fault MVA
69. D. Base load Plant
70. B. 1000
Solution :
(
71.
72. D. 215
Solution :
)
)(
)
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
(
)(
)(
)
(
)( )(
)
73. B. 100 A
Solution :
74. B. 220
75.
76.
77.
78. B. 5
Solution :
√( * (
)
( )(
)( )
)( )
79.
Solution :
(
(
)
80. C 3 46 Ω
Solution :
√( )( )( )
)
(
(
(
)(
)(
)
)( )
81. C. 75 %
Solution :
(
(
)(
)(
)(
)
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
82. A. Bandwith is 200 Hz
Solution :
83. A. Moving electric charge
84.
85. D. 0337
Solution :
√ (
(
)
*
70.28
(
)
)
86.
87. B. 1200 A
Solution :
(
)
(
)( )(
)
)(
)
88. D. 3300A
Soltuion :
(
(
)(
)
)
(√ )(
89. B. 36
Solution :
(
*
( )(
*
90. D. can have either a positive or negative charge
91.
Solution :
(
)(
)
(
)( )(
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
5
92. D. 0.25 H
Solution :
93. B. two winding transformer with the short circuit secondary
94. A. 25, 653
Solution :
(
)( )
(
)
(
𝐶
)(
(
)(
)
)
𝐶
(
)( 𝐶
)
(
)
95. D. 127 cis (-120)
Explanation : since it positive sequence the rotation of Vbc is -120
96.
97.
98. B. 1500 ohms
Solution:
99. A. 37.18 km
Solution :
( )(√ )(
(
100. A. 836.7 A
)
)(
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2015
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
√
√
MARCH 2016
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1. The color yellow reserved for se in equipment grounding conductor is
A. Yellow
B. Green
C. White
D. Gray
2. What is the emf induced across an inductor with 150mH inductance and
current of 4 amperes?
A. 0.6v
B. 0v
C. 1.2v
D. 12v
3. Which of the following is not a full-duplex?
A. Radar
B. Telephone
C. Tolemetry
D. Local Area Network
4. In a circuit breaker, the time duration from the instant of the fault extinction of
arc is known as
A. Operating time
B. total clearing time
C. Lag time
D. lead time
5. A resistance of 6 ohms is connected in parallel with another resistor R across
a 120v supply. The total current drawn from a supply was found to be 40A. What
is the value of resistance R.
A. 1 ohms
B. 2 ohms
SOLUTION:
Z= V/ I
Z= 120V/ 40A = 30 ohms
Current in R1= V/ R
= 120/ 6= 20A
R2= V/ I
C. 4 ohms
D. 6 ohms
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
= 120V/ 20 = 6 ohms
Answer: D. 6 ohms
6. A 50 cm long is moved in a field of density 1Wb/m squared at a velocity of
30m/s. what is the emf induced if the motion is perpendicular to the field?
A. 150v
B. 1.5v
C.15v
D. 0.15v
SOLUTION:
e= BLvsin Ф
= (1)(50x 10^-2)(30)(sin 90)
= 15v
Answer: C. 15v
7. Two capacitors C1= 50uF and C2= 30uF are connected in series. Find the
equivalent capacitance in uF.
A .1,875
B. 187.5
SOLUTION:
C total = ((C1-1) + (C2-1))-1)
= ((50uF-1) + (30uF-1))-1)
= 18.75 uF
Answer: C. 18.75 uF
C. 18.75
D. 1.875
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
8. 34.5 KV to 69 KV is classified as
A .Low voltage
B. Medium voltage C. High voltage
D. Extra high vol.
9. Wavelength is the distance travelled by an electronic wave during the time of
one cycle. Given a wavelength of 12 meters, what is the frequency?
A. 250 KHZ
B. 25KHz
C. 250MHZ
D. 25MHZ
SOLUTION:
F = VC/ wavelength
= (3x108) / 12
= 25MHZ
Answer: D. 25MHZ
10. A 4 pole dc generator has total of 600 conductors in its lap wound armature.
The flux per pole is 108 lines. Determine the generated emf if it is driven at 2400
rpm.
A. 230v
B. 254v
SOLUTION:
Eg= PZON/ 60a
= ((4)(600)(105)(2400)/ 60(4))* 10-8
= 240V
Answer: D. 240V
C. 234v
D. 240v
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
11. For an RL circuit, the power factor cannot be less than ______ or greater
than _____.
A .0,1
B. 1,0
C. 0, -1
D. -1, 0
12. In a certain country, the peak power demand for year 2005 is 9027 MW and
by year 2014 it is estimated to be 10064 MW. Calculate the growth rate.
A. 0.9 %
B. 0.8%
C. 0.76%
D. 0.85%
SOLUTION:
F= Pern
10,064= 9287er(9)
r= 0.89 %
Answer: A. 0.9%
13. __________ is the overall energy program formulated and updated yearly by
the DOE, submitted to the congress pursuant to RA 7638.
A. Philippine Energization Program
C. Philippine Electrification Program
B. Philippine Energy Plant
D. Philippine Electrification Plan
14. A certain amount of fuel can be converted into 3x10 quads of energy.
Assume 30% overall efficiency for the power plant. If the average load on the
power plant over a 24 hr period is 60MW, how long in days the fuel will last?
A. 180
B. 175
C. 183
D. 185
15. The lighting load for a dwelling expressed in terms of a unit load in volt
ampere per square meter must be at least _______.
A. 24
B. 12
C. 16
D. 2
16. The capacitors of power factor correction are rated in terms of
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. KV
B. KW
C. KVA
D. KVAR
17. Find the maximum power drawn from a 12v battery its internal resistance is
0.25.
A. 72W
B. 144W
C. 576W
D. 36W
SOLUTION:
P= V2/ 4R
= (12v)2/ 4(0.25)
= 144W
Answer: B. 144W
18. Two identical coupled coils have an equivalent inductance of 80mH when
connected in series aiding and 35mH in series opposing. What is the value of the
coefficient of coupling K.
A. 0.391
SOLUTION:
M = (Lta – Lto)/ 4
= (80 – 35)/ 4
= 11.25 mH
Lta= 2L+ 2M
80= 2L+ 2(11.25)
B. 0.319
C. 0.193
D. 0.139
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
L= 28.75mH
K= M/ sq. rt of (L1L2)
= 11.25/ sq. rt of (28.752)
= 0.391
Answer: A. 0.391
19. What is the emf induced in a coil of 500 turns and with a constant flux of 10 8
maxwells?
A. 0v
B. 5v
C. 50v
D. 500v
20. In a balanced three phase wye connected circuit, the ine voltage are equal
A. To the line current
C. and so are the line currents
B. To the phase voltage
D. but the line currents are unequal
21. If a given circuit when the power factor is unity the reactive power is
B. equal to i2r
A. Maximum
C. zero
D. minimum
22. What is the branch ampacity of a hermectic motor with a full load current of
16A?
A. 15A
B. 20A
SOLUTION:
Ampacity = Current full load x 80%
= 16x 80%
= 20A
C. 25A
D. 30A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Answer: B. 20A
23. A three phase wye delta connected, 50MVA, 345/ 34.5 Kv transformer is
protected by differential protection. The current transformer on the high side for
differential protection is 150:5. What is the current on the secondary side of
CT’s?
A. 3.83A
B. 2.53A
C. 4.50A
D. 4.83A
SOLUTION:
a=
Ip=
= 144.93 A
a=
=
Is=
(
)( )
Is=4.831 A
Answer: D. 4.831 A
24. Joule found out that the heat produced in a current carrying conductor is
proportional to
A. The square of the current
C. the square of resistance
B. The current
D. inversely proportional to time
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
25. A conductor has four identical strands arranged in diamond configuration.
Find the GMR of the conductor in terms of the radius r of each strand.
A. 1.6921r
B. 1.7037r
C. 1.3008r
D. 1.3052r
26. The resistance of the same length f aluminum and copper wires are found to
be equal. Find the ratio of radii of aluminum to copper.
A. 0.78
B. 1.29
C. 0.88
D. 1.14
27. In a wye connected system, line current is
A. 0.707 times the phase current
C. equal to the phase current
B. 1.735 times the phase current
D. 1.414 the phase current
28. What is the device function number for overcurrent relay?
A. 27
B. 67
C. 50
D. 51
29. In a series RL circuit, the inductor current ________ the resistor current.
A. Tags
B. leads
C. is equal to
D. is greater than
30. A three phase, 60Hz, transmission line has its conductors arranged in a
triangular configuration so that the two distances between conductors are 5m
and the third is 8m. the conductors have an outside diameter of 250 mils. Find
the inductive reactance in ohm per km per phase of the transmission line.
A. 0.567
B. 0.283
SOLUTION:
GMD = √(
)(
GMD = 5.84m
R=
x
R=0.7788
)(
)
C. 0.586
D. 0.293
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
GMR=0.7788x0.3175
GMR=0.247cm
L=(2x10-7) ln
L=1.55
XL=2 fL
=2 (60)(1.55x10-6)(1000)
ϕ
XL= 0.586
Answer: C. 0.586
31. Natural gas has an energy content of 0.036 watt- year/ ft3, and coal has an
average energy content of 640 watt-years/ton. If 2o percent of the net energy
requirement of 2.82x 108 GHWR were to be met with gas and 80 percent with
coal, what amount of gas would be required?
A. 1.79x106ft3
B. 1.79x108ft3
C1.79x1010ft3
D. 1.79x1012ft3
32. When one coil of a magnetically coupled pair has a current of 5A, the
resulting fluxes Ф11 Ф12 are 0 4mWb and 0 8mWb, respectively If turns are N1=
500 and N2= 1500, find L1.
A. 20mH
B. 40mH
SOLUTION:
L=
=
(
)
L= 120 Mh
Answer: D. 120mH
C. 60mH
D. 120Mh
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
33. Three capacitances C1= 6uF, C2= 7uF and C3= 18uF are connected in
series across a 120v supply. Find the voltages across C3.
A. 1.826v
B. 18.26v
C. 54.78v
D. 5.487v
SOLUTION:
C total = ((C1-1)+ (C2-1)+ (C3-1))-1
= ((6-1)+ (7-1)+ (18-1))-1
= 2.73uF
Q = CV
= (2.73uF)(120v)
= 327.6 uC
V = Q/ C
= 327.6 uC/ 18uF
= 18.26v
Answer: B. 18.26V
34. The specific resistance p is defined as
A. Resistance of a conductor which has a length of 1m and cross section of
1 m squared at 2o Celsius.
B. Resistance of any conductor at 25 celsius
C. Resistance of any conductor at 20 celsius
D. Resistance of a conductor which has a length of 1m and cros section of 1 cm
squared at 20 celsius.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
35. A 15 ohm resistor connected in series with an inductor has an equivalent
impedance of 30 ohms with an unknown angle. Find the power factor angle in
degrees.
A. 30
B. 60
C. 45
D. 75
SOLUTION:
Cos θ =
Θ = Cos-1 ( )
Θ= 60o
Answer: B. 60o
36. The master control center for a cellular telephone system in the
A. Cell site
C. central office
B. Mobile telephone switching office
D. branch office
37. The permeability of a material means
A. Strength of permanent magnet
B. Strength of an electromagnet
C. The magnetization left in the iron after exciting field has been removed.
D. The conductivity of a material for magnetic lines of force
38
A 10KVA, 200/400v, 1Ф transformer is operated with pen circuited
secondary. Find the primary current.
A. 2A
B. 4A
C.6A
D.8A
39. An office has a total of 500 square meters. Find the total lighting load for a
unit of 28 volt-amperes per square meter.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 8KVA
B. 10KVA
C. 12KVA
D. 14KVA
SOLUTION:
Load= (28volt- ampere per square meter)(500 square meter)
= 14KVA
Answer: D. 14KVA
40. Is an instrument connected across the load?
A. Voltmeter
B. ammeter
C. ohmmeter
D. wattmeter
41. A balanced delta load of 3+j4 ohms per phase is connected to a balanced
110v source. Find the line current.
A. 22A
B. 38.1A
C. 11A
D. 19.05A
SOLUTION:
I = sq. rt of (V)/ Z
= sq.rt. of (110v)/ 3+j4 ohms)
= 38.1A
Answer: B. 38.1A
42. Transform the current given by 6+j8 A to its time domain.
A. 100 cos (wt + 53.13)
B. 10cos (wt + 53.13)
C. 100 cos (wt + 36.78)
D. 10 cos (wt + 36.78)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SOLUTION:
I = 6 +j8 A
= 10 < 53.13
Answer: B. 10cos (wt + 53.13)
43. What is the equivalent phasor of i(t) = 20 cos(wt + 40) A?
A. 15.3- j2.9 A
B. -15.3+ j12.9 A
C. 15.3 + j12.9 A
D. -15.3 – j12.9 A
SOLUTION:
i(t) = 20 cos(wt + 40) A
i= 20< 40 A
= 15.3 + j12.9 A
Answer: C. 15.3 + j12.9 A
44. A parallel RL circuit draws a total current of 17A and 1.8KW from a 120V
supply. Find R.
A. 7 ohms
SOLUTION:
P = V2/ R
B. 8 ohms
C. 9 ohms
D. 10 ohms
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1800 w = 1202/ R
R= 8 ohms
Answer: B. 8 ohms
45. What will happen to the current of a transformer when the temperature of the
transformers winding increases?
A. remains unchanged
C. decreases
B. increases
D. dramatically unchanged
46. A 6 ohms resistor is connected in series with an inductor L across a 110v,
60Hz source and draws of a current of 10A. Find L.
A. 25.5mH
B. 26.5mH
SOLUTION:
Z= V/ I
= 110v/ 10A
= 11 ohms
Z2= R2+ Xc2
112= 62 + Xc2
Xc= 9.21 ohms
L= 9.21/ 2pi(60)
= 24.5 mH
Answer: D. 24.5mH
C. 23.5mH
D. 24.5Mh
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
46. The type of emf induced by neighboring coils.
A. Self- induced
C. dynamically induced
B. statically induced
D. mutually induced
47. Transformer are use to change the value of the following EXCEPT.
A. Alternating current
C. power
B. Alternating voltage
D. resistance
48 The power factor of a 20 MW , 13 2 KV, 3Ф motor is corrected to 0 9 a 230uF
capacitor. What is its initial power factor
A. 0.628
B. 0.965
C. 0.765
D. 0.828
SOLUTION:
Ф1= tan-1 ((2pi x 60 x 230uF x (13.2KV/ sq. rt. Of 3))/ (20MW/ 3)) + tan 25.84
= 51. 10
pf= cos 51. 10
= 0.628
Answer: A. 0.628
49. Two 6- ohm resistors are connected in series. When a resistor R is parallel
with one of them, the total resistance is ohms. What is the value of R?
A. 5 ohms
SOLUTION:
B. 6 ohms
C. 7 ohms
D. 8 ohms
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
6+ (6R/ 6+R)= 9
R= 6 ohms
Answer: B. 6 ohms
50. A coil of wire wound, with or without a magnetic core designed to have a
higher self-inductance than a straight wire.
A. Toroid
B. Solenoid
C. Inductor
D. Inductive Relay
51. What capacitance must be placed in series with an inductance of 0.05 henry,
so that when the frequency is 100 Hz, the impedance becomes equal to the
ohmic resistance?
A. 50.7 µF
B. 31.8 µF
C. 67.5 µF
D. 42 µF
SOLUTION:
Fr=100 HZ
L=0.5H
Fr= 1/2pi√ 𝐶
100=1/2pi√( )(𝐶)
C=50.7 µF
Answer: A. 50.7 µF
52. When a dc motor has no load, what will happen to the back emf?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. Reduces
C. Becomes Maximum
B. Increases
D. Becomes Zero
53. A three-phase induction motor has a nameplate speed of 1,720 rpm. What is
the rotor frequency?
A. 1.8 Hz
B. 2.7 Hz
C. 5Hz
D. 4.4 Hz
SOLUTION:
F= 60 Hz, Nr
Fr=%S x f
%S=
Fr=4.4% x60Hz
%S=
FR = 2.7 Hz
%S=4.4%
Answer: B. 2.7 Hz
54. A 50 MW coal-fired power plant has an average heat rate of 11,000
BTU/kWHR. Coal has a heating value of 13,000 BTU per pound. The plant has a
load factor of 80%. How much coal is burned per day?
A. 8.1 x 105 lb
B. 8.1 x 105 lb
C. 1.2 x 105 lb
SOLUTION:
(
)(
) (
) (
Answer: B. 8.1 x 10^5 lb/day
)(
)
D. 7.2 x 105 lb
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
55. Three identical resistors are connected in wye across 220 v, 3-phase lines.
The line current is12.7 A. To what value in volts should the line voltage be
changed the same line current with the resistors connected in delta?
A. 98.6
B. 132.8
C. 120
D. 73.3
SOLUTION:
VL Delta=12.7(10) = 127v
V
IL= 12.7A
Vphase =
√
73.32 v
Answer: D. 73.32 v
56. A sinusoidal current having peak value 7.07 A is superimposed on dc of 5 A.
If a hot-wire ammeter is used to measure the combined current in the circuit, it
will indicate ___ amperes.
A. 7.07
B. 10
C. 12.07
D. 2.07
57. A 4-way switch controls a lamp from _______ different locations.
A. 1
B. 2
C. 3
D. 4
58. When a V-V system is converted into Δ-Δ system, increase in the capacity of
the system is _____ percent.
A. 86.8
B. 73.2
C. 66.6
D. 50
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
59. A small wind generator is designed to generate 50 kW of power at a wind
velocity of 25 miles per hour. What is the approximate blade diameter?
A. 9.98 m
B. 12.98 m
C. 11.98 m
D. 10.98 m
60. A synchronous generator having a subtransient reactance of 0.15 pu and
operating at 5 percent above its rated voltage supplies a synchronous motor
having a 0.20 pu subtransient reactance. The motor is connected to the
generator by a transmission line and a transformer of total reactance 0.305 pu. A
sudden three-phase fault occurs at the generator terminals. Determine the per
unit subtransient fault current.
A. –j7.079 pu
B. –j8.0789 pu
C. –j9.079 pu
D. –j10.079 pu
61. The capacitance between any two conductors of a three-phase, threeconductor cable is 2 µF. The cable operates at 11 kV line voltage and 50 Hz.
What is the charging current through the cable capacitance?
A. 7.98 A
B. 4 A
C. 6.93 A
D. 12 A
62. A meter has a full-scale current of 50 µA, what is its sensitivity?
2
Ω/
B 20 v/kΩ
SOLUTION:
Sensitivity = 1/ IFL
= 1/ 50x10-6
= 20 kΩ/V
nsw :
2
Ω/
C 50 kΩ/v
D. 50 µA/v
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
63. The current-carrying capacity of a copper wire having twice the diameter of
another copper wire is ______________ as great.
A. Twice
B. Half
C. 4 Times
D. 3 Times
SOLUTION:
D2=2d1
(
)
Answer: C. 4 times
64. In a 10-pole synchronous machine, 20 electrical degrees are equivalent to
how many mechanical degrees?
A. 2
B. 8
C. 4
D. 10
SOLUTION:
Electrical angle = (P/2) x Mechanical angle
20= (10/2)x mechanical degree
Mechanical degree= 4
Answer: C. 4
65. You have 120 volts at the panel and 115 volts at the volts at the load. What is
the percentage voltage drop?
A. 5%
B. 4.35%
SOLUTION:
C. 4.17%
D. 3%
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
VD=
VD= 4.17 %
Answer: C. 4.17%
66. A delta 3ᶲ, 4-wire secondary 230/115 v would have a high-leg to neutral
voltage of ________.
A. 208 v
B. 230 v
C. 277 v
D. 199 v
SOLUTION:
3
230/115
High-leg neutral = √ 115
= 119.19V
Answer: D. 199.19 v
67. The conductors of a three-phase transmission line are arranged in the form of
an equilateral triangle with sides of 6 m each. If the conductors are 500 mils in
diameter and the line is 25 km long, what is its inductance per phrase?
A. 35.5 mH
B. 3.55 mH
SOLUTION:
Dm= √( )( )( )=6m
Ds=r=500/2=250mils
C. 71 mH
D. 7.1 Mh
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
250 mils x 1 inch/1000mils x 1ft/12 inch x 1m/ 3.28ft= 6.3516x10 -3m
L=2x10-7 ln Dm/Ds= (2x10-7 ln (6/6.3516x10-3)(25000)=34.25Mh OR 34.Mh
Answer: A. 35.5mH
69. A 10-km long, single-phase short transmission line has0 5 < 60 Ω/km
impedance. The line supplies a 316.8 kW load at 0.8 power factor lagging. What
is the voltage regulation if the receiving and voltage is 3.3 kV?
A. 12.94 %
B. 16.94%
C. 14.94%
D. 10.94%
SOLUTION:
Z =0.5 cis 60 = 0.25+j0.43
Z= R+jxL
= 0 25 j 43 Ω/km x 10k
Z= 2 5 j 4 3Ω
R= 2 5Ω
XL=4 3Ω
Vr= 3.3 kv
Vs= √(
I=
√ (
)
(
)
)( )
I=120A
Vs= √(
Vs=3856.63v
%VR=
(
)(
))
(
(
)(
))
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
=
%VR=16.94%
Answer: B. 16.94%
70. The positive, negative, and zero sequence reactances of a 20-MVA, 13.2 KV
synchronous generator are 0.3 pu, 0.2 pu and 0.1 pu, respectively. The
generator is solidly grounded and is not loaded. A line to ground fault occurs on
phase a. neglecting all the resistances, determine the positive sequence of the
fault current.
A. 4,374A
B.1,458A
C.2,525 A
D.7,576A
SOLUTION:
L-G fault
√ (
√
(
)
(
)
)(
)
= 4373.89
= 1/3 If
= 1/3(4373.89)
=1458A
Answer: 1458 A
71. Converts energy of water to mechanical energy.
A. pump
B. turbine
C. generator
D. draft tube
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
72. Calculate the capacitance of a parallel plate capacitor having 20 cm x 20
cm square plates separated by a distance of 1 mm. Assume the dielectric
medium to be air with permittivity of 8.85 x 10-12 F/m.
A. 354 uF
B. 354 pF
C. 3.54 uF
D. 3.54 Pf
SOLUTION:
A= (.2x.2m) =0.4m
D= Imm =0.001m
∑
𝐶
=8.85x10 F/m
∑
[(
)( ) )]
Answer: 354 pF
73. A current of 10 A is flowing in a flexible conductor of length 1.5 m. A force of
15 N acts on it when it is placed in uniform field of 2 T. Calculate the angle
between the magnetic field and the direction of the current.
A. 90°
B. 60°
SOLUTION:
F=15N,
B=2T
I=10
L= 1.5m
F=BIL sin
15 = (2) n (10) (1.5) sin
C. 45°
D. 30°
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
=30
Answer: 30°
74. If the waveform of a current has form factor 1.2 and peak factor 1.7, find the
average value of the current if the maximum value of the current is 100 A.
A. 45 A
B. 47 A
C. 49 A
D. 51 A
SOLUTION:
Form factor =1.2
Peak factor = 1.7
Answer: C. 49.02
75. The applied voltage in a transformer is increased by 50 % and frequency is
reduced by 50 %. The maximum core flux density will become ______________.
A. same
B. 1.5 times
C. 3 times
D. 5 times
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
76. A device that establishes an electrical connection to the earth.
A. Grounding conductor
C. Grounding electrode
B. Grounded conductor
D. Grounding electrode conductor
77. A transformer has 4 % resistance and 6 % reactance drop. Find the voltage
regulation at full-load 0.8 p.f. lagging.
A. 6.8 %
B. 5.8 %
C. 4.8 %
D. 160%
SOLUTION:
%VR= √(
)
(
)
%VR= 6.8%
Answer: A. 6.8%
78. A 6-pole, 50 Hz, three-phase induction motor has a maximum torque of 200
N-m when it is running at a speed of 900 rpm. The resistance of the rotor is 0.25
Ω Neglecting stator impedance, determine the torque at 5 % slip
A. 180 N-m
B. 140 N-m
C. 150 N-m
D. 160 N-m
79. In a certain country, the equivalent fuel reserve for power generation is 3 x
106 MW-yoars. The present peak power demand is 200 GW, and the expected
power consumption growth rate is 2.1 percent. How long will the fuel reserve
last?
A. 8 years
B. 11 years
SOLUTION:
F=
Pern
3*106 = (200*103)0.021n
C. 13 years
D. 14 years
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
N= 13 years
Answer: C. 13 years
80. Which of the following is not a standard branch circuit among rating?
A. 15 A
B. 25 A
C. 30 A
D. 40 A
81. Once residual magnetism of a shunt generator is lost, it may be restored by
connecting its shunt field.
A. to earth
C. to an external battery
B. in reverse
D. to an alternator
82. Power in balance 3-phase system is measured by the two-wattmeter method
and it is found that the ratio of the two-wattmeter readings is 2 is to 1. What is the
power factor of the system?
A. 0.9
B. 0.82
C. 0.866
SOLUTION:
P1= 1 P2 =2
p.f = cos
[(√ )(
(
)]
)
= 30
p.f. = cos30° = 0.866
Answer: C. 0.866
D. 0.707
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
83. A coil with 40 ohm resistance and 0.02 H inductance and a pure capacitor
are connected in parallel across a 60 Hz supply. Find the value of the capacitor
in uF if the circuit is resonant.
A. 14.35
B. 12.07
C. 11.67
D. 15.82
SOLUTION:
F= 60
;
Fr=
√
60=
√
R=40 ;
(
)
(
)
L=0.02H
C = 12.07 µF
Answer: B. 12.07 µF
84. A balance delta connected load draws 100 A line current form a balanced 3phase supply. Determine the zero sequence components of the currents.
A. -50 – j86.6
B. 50 – j86.6
SOLUTION:
When delta connected (zero sequence)
Io= 0
Answer: D. 0
C. 86.6 – j50
D. 0
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
85. Surge impedance of tansmission line is given by:
A √C/L
B √LC
C 1/√LC
D √L/
86. In full-wave rectification, if the in-out frequency is 60 Hz, then output has a
frequency of ______
A. 120 Hz
B. 60 Hz
C. 30 Hz
D. 15 Hz
SOLUTION:
Fout = 2fin
Fout = 2(60Hz) = 120Hz
Answer: A. 120 Hz
87. Determine the total inductance of a single-phase overhead transimission line
of 10km long. The diameter of each conductor os 0.8 cm and the distance
between them is 1.2 meters.
A. 11.9 mH
B. 23.8 mH
SOLUTION:
L=4x1017 ln
=4x1017 ln
=
(
)
2.3815x10-6(10,000m)
L=23.81 Mh
C. 35.7 mH
D. 47.6 mH
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Answer: B. 23.8 mH
88. A diversity factor of 2 gives a saving of ___ % in generating equipment.
A. 33
B. 50
C. 67
D. 75
SOLUTION:
dF = 2
dF (saving) = 100%
2 (saving) = 1
Saving = 50%
Answer: B. 50%
89. A room 8 m x 12 m i slighted by 15 lamps wo fairl uniform illumination of 100
lumens per square meter. What is the coefficient of utilization if the output of
each lamp is 1,600 lumens.
A. 40 %
B. 60 %
SOLUTION:
100= (x*1600*15)/ (8*12)
X= 40%
Answer: A. 40%
C. 30 %
D. 50 %
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
90. A 440 -v, 70- HP shunt motor has an ammature of0 185 Ω and field
resistance of 350 Ω The current drawn byy this machine is 135 A at full-load. If
this machine is to deliver torque equal to 175 percent of that at full-load, what
would be the best resistance of its starter?
A 34 Ω
B 56 Ω
C 22 Ω
D
7 Ω
SOLUTION:
Ist= Vs/ (Ra+ Rst)
1.75(135) = 440/ (0.185+ Rst)
Rst= 1.67 ohms= 1.7ohms
Answer: D. 1.7 ohms
91.In a parallel Rc circuit, as the capcitance decreases, the power factor
___________.
A. Increases
B. decreases
C. Remains the same
D. Becomes zero
92. Find the amount of electrical energy expanded in raising the temperature of
45 liters of water by 75 C. Assume a heater efficiency of 90%.
A. 2.64 KWHR
SOLUTION:
M= 45L x
m=45kg
B. 3.46 KWHR
C. 4.36 KWHR
D.6.34 KWHR
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Q=45kg x
x 75degree C x
(
)(
)
Q = 4.36KWhr
Answer: C. 4.36 kWhr
93. A capacitor of 40 μF capacitance in series with 2,000 ohms is suddenly
connected across a 200-volt source. What is the energy stored in the capacitor
after 0.04 sec?
A. 0.124 J
B. 0.241 J
C. 0.412 J
D. 2.41 J
SOLUTION:
W = ½ (Q2/C)
= ½ ((It)2/ C)
= ½ ((0.1*0.04)2/ 40uF)
= 0.2
Answer: B.0.241J
94. Calculate the average voltage generated in a six-turn full-pitch coil of a 25cycle alternator if the flux pole is 7.2 x 10^5 maxwells.
A. 7.4 V
B. 8.64 V
SOLUTION:
F= 25Hz
= 7.2 x 10^5 maxwells
C. 1.08 V
D. 4.32 V
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
N= 6
Eave = 4 f N x 10^-8
= (25) (7.2x 10^5) (6) x 10^-8
Eave= 4.32 V
Answer: D. 4.32 V
95. A 13.8 kV/440 v, 50 kVA single-phase transformer has a leakage reactance
of 300 ohms referred to the 13.8 kV side. Determine the per unit value of the
leakage reactance of the low base.
A. 0.305
B. 0.40
C. 0.097
D. 0.079
SOLUTION:
S= V2/R
= (13800)2/300
= 634800
Per unit= 50000/ 634800
= 0.079
Answer: D. 0.079
96. A 100 km transmission line has a 1,000 ohms shunt reactance. What is the
per km shunt reactance?
A 1,000 Ω
SOLUTION:
B
,
Ω
C 10 Ω
D 100 Ω
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
100 km,
R = 1,000Ω
Rsh = 1000Ω/km 100km)
Rsh = 100,000 Ω
nsw : B
,
Ω
97. A 5,000 kVA synchronous condenser operates with a leading p.f. of 0.032.
The losses are 180 kW.
A. 5,160 kW
What is the power input to the motor?
B. 5,320 kW
C. 160 kW
D. 320 kW
SOLUTION:
Cos ϴ= P/ S
0.032= P/ 5000000
P= 160 KW
Answer: C. 160KW
98. The current flowing in the armature conductors of a dc motor is
A. ac
B. dc
C. ac as well as dc
D. Transients
99. The sequence components of phase c current of a 3-phase system are as
follows: Ic0=0, Ic1=18.4 cis88.4, Ic2=3.23 cis48.2. Find the phase b current in
amperes.
19.24 cis -218
B. 18 cis 42
C. 18 cid -42
D. 19.24 cis 218
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SOLUTION:
Ia1= (18.4<88.40) (1<120) = 18.4<- 151.6
Ia2= (3.23<48.2) (1<120) = 3.23<168.2
Ib= (18.4<- 151.6)(1<120)+ (3.23<168.2)(1<240)
= 19.23<-22 (1<240)
= 19.23<218
Answer: D. 19.24 cis 218
100. A current of 20 A is flowing i =n an RL series circuit the instant before the
switch is opened. If R = 10 Ω and L= 10 H, find the current after 3 second has
elapsed.
A. 1 A
B. 2 A
SOLUTION:
I= (E/R)(1- e –R/L(t))
= (200/10)(1-e-10/10(3))
= 19A
I= 20-19
= 1A
Answer:A.1A
C. 3 A
D. 4 A
AUGUST 2016
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1. The color yellow reserved for equipment grounding conductor is
A. Yellow
B. Green
C. White
D. Gray
2. What is the emf induced across an inductor with 150mH inductance and
current of 4 amperes?
GIVEN: L=150mH, I=4A
SOLUTION:
Emf=LI
Emf=(150mH)(4A)
=0.6V
A. 0.6v
B. 0v
C. 1.2v
D. 12v
3. Which of the following is not a full-duplex?
A. Radar B. Telephone
C. Tolemetry
D. Local Area Network
4. In a circuit breaker, the time duration from the instant of the fault extinction of
arc is known as
A. Operating time
B. total clearing time C. Lag time
D. lead time
5. A resistance of 6 ohms is connected in parallel with another resistor R across
a 120v supply. The total current drawn from a supply was found to be 40A.
What is the value of resistance R?
A. 1 ohm
B. 2 ohms
C. 4 ohms
D. 6 ohms
GIVEN: R=6ohms, V=120V, I=40A
SOLUTION:
Z= V/ I
Z= 120V/ 40A = 30 ohms
Current in R1= V/ R
= 120/ 6= 20A
R2= V/ I
= 120V/ 20
= 6 ohms
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Answer: D. 6 ohms
6. A 50 cm long is moved in a field of density 1Wb/m squared at a velocity of
30m/s. what is the emf induced if the motion is perpendicular to the field?
A. 150v
B. 1.5v
C.15v
D. 0.15v
GIVEN:
B=1Wb/m
L=50cm
v=30m/s
SOLUTION:
e= BLvsin Ф
= (1)(50x 10^-2)(30)(sin 90)
= 15v
Answer: C. 15v
7. Two capacitors C1= 50uF and C2= 30uF are connected in series. Find the
equivalent capacitance in uF.
A. 1,875
B. 187.5
C. 18.75
D. 1.875
GIVEN: C1= 50uF and C2= 30uF
SOLUTION:
C total = ((C1-1) + (C2-1))-1)
= ((50uF-1) + (30uF-1))-1)
= 18.75 uF
8. 34.5 KV to 69 KV is classified as
A. Low voltage B. Medium voltage C. High voltage
D. Extra high vol.
Answer: According to Phillipine Distribution Code, A Voltage exceeding 34.5
Kv upto 230kV is considered as High Voltage
C. High Voltage
9. Wavelength is the distance travelled by an electronic wave during the time of
one cycle. Given a wavelength of 12 meters, what is the frequency?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 250 KHZ
B. 25KHz
C. 250MHZ
D. 25MHZ
GIVEN:
VC=3x108 m/s (speed of light)
Wavelength=12m
SOLUTION:
F = VC/ wavelength
= (3x108) / 12
= 25MHZ
10. A 4 pole dc generator has total of 600 conductors in its lap wound armature.
The flux per pole is 108 lines. Determine the generated emf if it is driven at
2400 rpm.
A. 230v
B. 254v
C. 234v
D. 240v
GIVEN: P=4, Z=600, O=105 , N=2400
SOLUTION:
Eg= PZON/ 60a
= ((4)(600)(105)(2400)/ 60(4))* 10-8
= 240V
Answer: D. 240V
11. For an RL circuit, the power factor cannot be less than ______ or greater than
_____.
A. 0,1
B. 1,0
C. 0, -1
D. -1, 0
Explanation : Power factor is the ration of the actual electrical power
dissipated by an AC circuit to the product of RMS values of its current and
voltage. Since you can never use more power than what is flowing through
your circuit, this ratio or power factor can never be more than 1 and less than
0.
12. In a certain country, the peak power demand for year 2005 is 9027 MW and
by year 2014 it is estimated to be 10064 MW. Calculate the growth rate.
A. 0.9 %
B. 0.8%
C. 0.76%
D. 0.85%
GIVEN : (From Continuously Compounding Periods topic)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
P = 9207 (present value)
f = 10,064 (future value)
r = ? (periodic interest rate)
n = 2014-2005 = 9 (number periods)
Find r.
SOLUTION :
F= Pern
10,064= 9287er(9)
r= 0.89 %
Answer: A. 0.9%
13. __________ is the overall energy program formulated and updated yearly by
the DOE, submitted to the congress pursuant to RA 7638.
A. Philippine Energization Program C. Philippine Electrification Program
B. Philippine Energy Plan
D. Philippine Electrification Plan
14. A certain amount of fuel can be converted into 3x10 quads of energy. Assume
30% overall efficiency for the power plant. If the average load on the power
plant over a 24 hr period is 60MW, how long in days the fuel will last?
A. 180
B. 175
C. 183
D. 185
SOLUTION :
1 Quad = 2.93x10^9 Mwh
0.003 Quad = 8.79x10^5
In 24 hrs: 60 x 24 = 1440 Mwh
At 30% efficiency : 1440/0.3 = 4800 Mwh
Hence, fuel will be consumed in : 8.79x10^5/4800 = 183.125 days
15. The lighting load for a dwelling expressed in terms of a unit load in volt
ampere per square meter must be at least _______.
A. 24
B. 12
C. 16
D. 2
16. The capacitors of power factor correction are rated in terms of
A. KV
B. KW
C. KVA
D. KVAR\
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Explanation : KVAR means Kilo Volt Ampere Reactive. Leading Reactive
Power is produced by synchronous Capacitors and Capacitor banks.
Consumed by Capacitive nature of Loads.
17. Find the maximum power drawn from a 12v battery its internal resistance is
0.25.
72W
B. 144W
C. 576W
D. 36W
SOLUTION:
P= V2/ 4R
= (12v)2/ 4(0.25)
= 144W
Answer: B. 144W
18. Two identical coupled coils have an equivalent inductance of 80mH when
connected in series aiding and 35mH in series opposing. What is the value of
the coefficient of coupling K.
A. 0.391
B. 0.319
C. 0.193
D. 0.139
SOLUTION:
M = (Lta – Lto)/ 4
= (80 – 35)/ 4
= 11.25 mH
Lta= 2L+ 2M
80= 2L+ 2(11.25)
L= 28.75mH
K= M/ sq. rt of (L1L2)
= 11.25/ sq. rt of (28.752)
= 0.391
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Answer: A. 0.391
19. What is the emf induced in a coil of 500 turns and with a constant flux of 10 8
maxwells?
A. 0v
B. 5v
C. 50v
D. 500v
Explanation : According to Faraday’s Law of induction, an electromotive
force needs a rate of change of flux (dB/dt) to be induced. Since flux is
constant, the induced emf is zero.
20. In a balanced three phase wye connected circuit, the line voltage are equal
A. To the line current
C. and so are the line currents
B. To the phase voltage
D. but the line currents are unequal
21. In a given circuit when the power factor is unity the reactive power is
A. Maximum
B. equal to i2r
C. zero
D. minimum
22. What is the branch ampacity of a hermectic motor with a full load current of
16A?
A. 15A
B. 20A
C. 25A
D. 30A
Solution:
Ampacity = Current full load x 125%
= 16 x 1.25
= 20A
Answer: B. 20A
23. A three phase wye delta connected, 50MVA, 345/ 34.5 Kv transformer is
protected by differential protection. The current transformer on the high side
for differential protection is 150:5. What is the current on the secondary side
of CT’s?
A. 3.83A
B. 2.53A
C. 4.50A
D. 4.83A
Solution:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
IL-Primary =
√
= 83.67A
Since wye connected , IL-Primary = IØ-Primary = 83.67A
a=
IØ-Secondary = 2.789A
IL-secondary = √ x 2.789A
IL-secondary = 4.83A
Answer: D. 4.83A
24. Joule found out that the heat produced in a current carrying conductor is
proportional to
A. The square of the current
C. the square of resistance
B. The current
D. inversely proportional to time
25. A conductor has four identical strands arranged in diamond configuration.
Find the GMR of the conductor in terms of the radius r of each strand.
A. 1.6921r
B. 1.7037r
C. 1.3008r
D. 1.3052r
Solution:
d1 = 2r = d2 = d3, d4 = 2√ r
GMR = √
GMR = √(
GMR = 1.6921r
Answer: A. 1.6921r
)
(
√
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
26. The resistances of the same length of aluminum and copper wires are found
to be equal. Find the ratio of radii of aluminum to copper.
A. 0.78
B. 1.29
C. 0.88
D. 1.14
Solution:
ρaluminum = 17 , ρcopper = 10.37
therefore r = √
R=
√
√
Answer: B. 1.29
27. In a wye connected system, line current is
A. 0.707 times the phase current
C. equal to the phase current
B. 1.735 times the phase current
D. 1.414 the phase current
28. What is the device function number for overcurrent relay?
A. 27
B. 67
C. 50
D. 51
29. In a series RL circuit, the inductor current ________ the resistor current.
A. Tags B. leads
C. is equal to
D. is greater than
30. A three phase, 60Hz, transmission line has its conductors arranged in a
triangular configuration so that the two distances between conductors are 5m
and the third is 8m. the conductors have an outside diameter of 250 mils. Find
the inductive reactance in ohm per km per phase of the transmission line.
A. 0.567
B. 0.283
C. 0.586
D. 0.293
Solution:
d = 250mils x
r=
= 6.35x
= 3.175
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
GMR = 0.7788r = 0.7788(3.175
GMD = √(
)(
)(
L = (2 x
) ln(
= (2 x
) ln (
) = 2.47
) = 5.848m
)
)
= 1.55x
XL = 2πfL
XL = 2π(60)( 1.55x
XL = 0.586
)(1000)
/Ø
Answer: C. 0.586
31. Natural gas has an energy content of 0.036 watt- year/ ft3, and coal has an
average energy content of 640 watt-years/ton. If 2o percent of the net energy
requirement of 2.82x 108 GHWR were to be met with gas and 80 percent with
coal, what amount of gas would be required?
A. 1.79x106ft3
B. 1.79x108ft3
C1.79x1010ft3
D. 1.79x1012ft3
32. When one coil of a magnetically coupled pair has a current of 5A, the
resulting fluxes Ф11 Ф12 are 0 4mWb and 0 8mWb, respectively If turns are
N1= 500 and N2= 1500, find L1.
A. 20mH
B. 40mH
C. 60mH
D. 120mH\
Solution :
Ф11= 4mWB
Ф12= 8mWB
Ф1= Ф11 Ф12
= .4 + .8
Ф1= 1 2mWB`
Answer: D. 120mH
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
33. Three capacitances C1= 6uF, C2= 7uF and C3= 18uF are connected in
series across a 120v supply. Find the voltages across C3.
A. 1.826v
B. 18.26v
C. 54.78v
D. 5.487v
SOLUTION:
C total = ((C1-1)+ (C2-1)+ (C3-1))-1
= ((6-1)+ (7-1)+ (18-1))-1
= 2.73uF
Q = CV
= (2.73uF)(120v)
= 327.6 uC
V = Q/ C
= 327.6 uC/ 18uF
= 18.26v
Answer: B. 18.26V
34. The specific resistance p is defined as
A. Resistance of a conductor which has a length of 1m and cross section
of 1 m squared at 2o Celsius.
B. Resistance of any conductor at 25 celsius
C. Resistance of any conductor at 20 celsius
D. Resistance of a conductor which has a length of 1m and cros section of 1 cm
squared at 20 celsius.
35. A 15 ohm resistor connected in series with an inductor has an equivalent
impedance of 30 ohms with an unknown angle. Find the power factor angle in
degrees.
A. 30
B. 60
C. 45
D. 75
36. The master control center for a cellular telephone system in the
A. Cell site
C. central office
B. Mobile telephone switching office D. branch office
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
37. The permeability of a material means
A. Strength of permanent magnet
B. Strength of an electromagnet
C. The magnetization left in the iron after exciting field has been removed.
D. The conductivity of a material for magnetic lines of force
38. A 10KVA, 200/400v, 1Ф transformer is operated with pen circuited secondary
Find the primary current.
A. 2A
B. 4A
C.6A
D.8A
Solution :
S=VI
I=10KVA/4KV
I= 2.5A
Answer: A. 2A
39. An office has a total of 500 square meters. Find the total lighting load for a
unit of 28 volt-amperes per square meter.
A. 8KVA
B. 10KVA
C. 12KVA
D. 14KVA
SOLUTION:
Load= (28volt- ampere per square meter)(500 square meter)
= 14KVA
Answer: D. 14KVA
40. Is an instrument connected across the load?
A. Voltmeter
B. ammeter
C. ohmmeter
D. wattmeter
41. A balanced delta load of 3+j4 ohms per phase is connected to a balanced
110v source. Find the line current.
A. 22A
SOLUTION:
B. 38.1A
C. 11A
D. 19.05A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
I = sq. rt of (V)/ Z
= sq.rt. of (110v)/ 3+j4 ohms)
= 38.1A
Answer: B. 38.1A
42. Transform the current given by 6+j8 A to its time domain.
A. 100 cos (wt + 53.13) B. 10cos (wt + 53.13)
cos (wt + 36.78)
C. 100 cos (wt + 36.78)
D. 10
What is the equivalent phasor of i(t) = 20 cos(wt + 40) A?
A. 15.3- j2.9 A
B. -15.3+ j12.9 A
SOLUTION:
C. 15.3 + j12.9 A
D. -15.3 – j12.9 A
SOLUTION:
i(t) = 20 cos(wt + 40) A
I = 6 +j8 A
= 10 < 53.13
i= 20< 40 A = 15.3 + j12.9 A
Answer: B. 10cos (wt + 53.13)
Answer: C. 15.3 + j12.9 A
43. A parallel RL circuit draws a total current of 17A and 1.8KW from a 120V
supply. Find R.
A. 7 ohms
SOLUTION:
P = V2/ R
1800 w = 1202/ R
R= 8 ohms
Answer: B. 8 ohms
B. 8 ohms
C. 9 ohms
D. 10 ohms
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
44. What will happen to the current of a transformer when the temperature of the
transformers winding increases?
A. remains unchanged
dramatically unchanged
B. increases
C. decreases
D.
46. A 6 ohms resistor is connected in series with an inductor L across a 110v,
60Hz source and draws of a current of 10A. Find L.
A. 25.5mH
B. 26.5mH
C. 23.5mH
D. 24.5Mh
SOLUTION:
Z= V/ I
= 110v/ 10A
= 11 ohms
Z2= R2+ Xc2
112= 62 + Xc2
Xc= 9.21 ohms
L= 9.21/ 2pi(60)
L= 24.5 Mh
Answer: D. 24.5 Mh
47. The type of emf induced by neighboring coils.
A. Self- induced C. dynamically induced
D. mutually induced
B.statically induced
48. Transformer are use to change the value of the following EXCEPT.
A. Alternating current
B. Alternating voltage
C. power
D. resistance
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
49 The power factor of a 20 MW , 13 2 KV, 3Ф motor is corrected to 0 9 a 230uF
capacitor. What is its initial power factor
A. 0.628
B. 0.965
C. 0.765
D. 0.828
SOLUTION:
Ф1= tan-1 ((2pi x 60 x 230uF x (13.2KV/ sq. rt. Of 3))/ (20MW/ 3)) + tan 25.84
= 51. 10
pf= cos 51. 10
= 0.628
Answer: A. 0.628
50. Two 6- ohm resistors are connected in series. When a resistor R is parallel
with one of them, the total resistance is ohms. What is the value of R?
A. 5 ohms
B. 6 ohms
C. 7 ohms
D. 8 ohms
SOLUTION:
6+ (6R/ 6+R)= 9
R= 6 ohms
Answer: B. 6 ohms
46. A coil of wire wound, with or without a magnetic core designed to have a
higher self-inductance than a straight wire.
A. Toroid B. Solenoid C. Inductor D. Inductive Relay
47. What capacitance must be placed in series with an inductance of 0.05 henry,
so that when the frequency is 100 Hz, the impedance becomes equal to the
ohmic resistance?
A. 50.7 µF
B. 31.8 µF
C. 67.5 µF
D. 42 µF
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SOLUTION:
Fr=100 HZ
L=0.5H
Fr= 1/2pi√ 𝐶
100=1/2pi√( )(𝐶)
C=50.7 µF
Answer: A. 50.7 µF
48. When a dc motor has no load, what will happen to the back emf?
A. Reduces
C. Becomes Maximum
B. Increases
D. Becomes Zero
49. A three-phase induction motor has a nameplate speed of 1,720 rpm. What is
the rotor frequency?
A. 1.8 Hz
B. 2.7 Hz
C. 5Hz
D. 4.4 Hz
SOLUTION:
F= 60 Hz, Nr
Fr=%S x f
%S=
Fr=4.4% x60Hz
%S=
FR = 2.7 Hz
%S=4.4%
Answer: B. 2.7 Hz
50. A 50 MW coal-fired power plant has an average heat rate of 11,000
BTU/kWHR. Coal has a heating value of 13,000 BTU per pound. The plant
has a load factor of 80%. How much coal is burned per day?
A. 8.1 x 105 lb
B. 8.1 x 105 lb
C. 1.2 x 105 lb D. 7.2 x 105 lb
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SOLUTION:
(
)(
) (
) (
)(
)
Answer: B. 8.1 x 10^5 lb/day
51. Three identical resistors are connected in wye across 220 v, 3-phase lines.
The line current is12.7 A. To what value in volts should the line voltage be
changed the same line current with the resistors connected in delta?
A. 98.6
B. 132.8
C. 120
D. 73.3
SOLUTION:
VL Delta=12.7(10) = 127v
V
IL= 12.7A
Vphase =
√
73.32 v
Answer: D. 73.32 v
52. A sinusoidal current having peak value 7.07 A is superimposed on dc of 5 A.
If a hot-wire ammeter is used to measure the combined current in the circuit,
it will indicate ___ amperes.
A. 7.07
B. 10
C. 12.07
D. 2.07
53. A 4-way switch controls a lamp from _______ different locations.
A. 1
B. 2
C. 3
D. 4
54. When a V-V system is converted into Δ-Δ system, increase in the capacity of
the system is _____ percent.
A. 86.8
B. 73.2
C. 66.6
D. 50
55. A small wind generator is designed to generate 50 kW of power at a wind
velocity of 25 miles per hour. What is the approximate blade diameter?
A. 9.98 m
B. 12.98 m
C. 11.98 m
D. 10.98 m
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SOLUTIONS
P=1/2pAv^3CP
convert miles per hour into meter per
second
P=Power
25 miles per hour=11.176 meter per second
p=Air Density
solving for diameter
A=Area(pi(r)^2) or (piD^2/4)
P=1/2pAv^3CP
v^3= Velocity
=½ (1.226) (11.176)^3(piD^2/4)(.59)
CP=Power Coefficient
51.
=11=10.98
A synchronous generator having a subtransient reactance of 0.15 pu and
operating at 5 percent above its rated voltage supplies a synchronous
motor having a 0.20 pu subtransient reactance. The motor is connected
to the generator by a transmission line and a transformer of total
reactance 0.305 pu. A sudden three-phase fault occurs at the generator
terminals. Determine the per unit subtransient fault current.
A. –j7.079 pu
B. –j8.0789 pu
C. –j9.079 pu
D. –j10.079 pu
SOLUTION:
Using Thevenin’s; @ gen
Zth =
)(
)
If = Vf/Zth = 1.05/j0.1156 = -j9.079 pu
Answer: C. –j9.079
52.
The capacitance between any two conductors of a three-phase, threeconductor cable is 2 µF. The cable operates at 11 kV line voltage and 50
Hz. What is the charging current through the cable capacitance?
A. 7.98 A
B. 4 A
C. 6.93 A
D. 12 A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SOLUTION:
CLN = 2CLL
CLN = 2 (2x10^-6) = 4x10^-6
XC = 1/2πfC
Xc = 1/2π 50 4x10^-6 = 795 775 Ω
I = VLN/XC
√
I
= 7.98 A
Answer: A. 7.98 A
53. A meter has a full-scale current of 50 µA, what is its sensitivity?
A. 2 Ω/
B 20 v/kΩ
C 50 kΩ/v
D. 50 µA/v
SOLUTION:
S = 1/I
S = 1/50x10^-6 = 20kΩ/V
Answer: A. 2
Ω/
54.
The current-carrying capacity of a copper wire having twice the diameter
of another copper wire is ______________ as great.
A. Twice
B. Half
C. 4 Times
D. 3 Times
SOLUTION:
D2=2d1
(
)
Answer: C. 4 times
55.
In a 10-pole synchronous machine, 20 electrical degrees are equivalent
to how many mechanical degrees?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 2
B. 8
C. 4
D. 10
SOLUTION:
E degree = P/2 x M degree
( )=4
Answer: C. 4
56.
You have 120 volts at the panel and 115 volts at the volts at the load.
What is the percentage voltage drop?
A. 5%
B. 4.35%
C. 4.17%
D. 3%
SOLUTION:
VD=
VD= 4.17 %
Answer: C. 4.17%
57.
A delta 3ᶲ, 4-wire secondary 230/115 v would have a high-leg to neutral
voltage of ________.
A. 208 v
B. 230 v
C. 277 v
D. 199 v
SOLUTION:
3
230/115
High-leg neutral = √ 115
= 119.19V
Answer: D. 199.19 v
58.
The conductors of a three-phase transmission line are arranged in the
form of an equilateral triangle with sides of 6 m each. If the conductors
are 500 mils in diameter and the line is 25 km long, what is its inductance
per phrase?
A. 35.5 mH
B. 3.55 mH
C. 71 mH
D. 7.1 Mh
SOLUTION:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
= 0.0127 m
r = 0.0127/2 = 6.35x10^-3
r’ = 0 7788r = 4 9454x10^-3
Length = 25km = 25,000 m
L per-phase = 2x10^-7
((
L per-phase = 2x10^-7
( )(
)
))(
) = 35.5 mH
Answer: A. 35.5 mH
A 10-km long, single-phase short transmission line has0 5 < 60 Ω/km
impedance. The line supplies a 316.8 kW load at 0.8 power factor
lagging. What is the voltage regulation if the receiving and voltage is 3.3
kV?
A. 12.94 %
B. 16.94%
C. 14.94%
D. 10.94%
59.
SOLUTION:
Z =0.5 cis 60 = 0.25+j0.43
Z= R+jxL
= 0 25 j 43 Ω/km x 10k
Z= 2 5 j 4 3Ω
R= 2 5Ω
XL=4 3Ω
Vr= 3.3 kv
Vs= √(
)
I=
√ (
(
)
)( )
I=120A
Vs= √(
(
)(
))
(
(
)(
))
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Vs=3856.63v
%VR=
=
%VR=16.94%
Answer: B. 16.94%
60.
The positive, negative, and zero sequence reactances of a 20-MVA, 13.2
KV synchronous generator are 0.3 pu, 0.2 pu and 0.1 pu, respectively.
The generator is solidly grounded and is not loaded. A line to ground fault
occurs on phase a. neglecting all the resistances, determine the positive
sequence of the fault current.
SOLUTION:
L-G fault
√ (
√
(
)
(
)
)(
)
= 4373.89
= 1/3 If
= 1/3(4373.89)
=1458A
Answer: 1458 A
71. Converts energy of water to mechanical energy.
A. pump
B. turbine
C. generator
D. draft tube
72. Calculate the capacitance of a parallel plate capacitor having 20 cm x 20
cm square plates separated by a distance of 1 mm. Assume the dielectric
medium to be air with permittivity of 8.85 x 10-12 F/m.
A. 354 uF
B. 354 pF
C. 3.54 uF
D. 3.54 Pf
Solution:
A = (20x10-2 m) (20x10-2 m)
= 0.04m2
d = 1x10-3m
Σo = 8.85x10-12 F/m
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1x10-3
C=
= 354pF
-12
= (8.85x10 )(1)(0.04)
73. A current of 10 A is flowing in a flexible conductor of length 1.5 m. A force of
15 N acts on it when it is placed in uniform field of 2 T. Calculate the angle
between the magnetic field and the direction of the current.
A. 90°
B. 60°
C. 45°
D. 30°
Solution:
I = 10A
L = 1.5m
F= 15N
β = 2T
F = βILsinØ
15 = (2)(10)(1.5)sinØ
Ø
˚
74. If the waveform of a current has form factor 1.2 and peak factor 1.7, find the
average value of the current if the maximum value of the current is 100 A.
A. 45 A
B. 47 A
C. 49 A
D. 51 A
Solution:
F = 1.2
P = 1.7
Imax = 100A
P=
;
RMS = 58.82A
F=
;
AVE = 49A
75. The applied voltage in a transformer is increased by 50 % and frequency is
reduced by 50 %. The maximum core flux density will become
______________.
A. same
B. 1.5 times
C. 3 times
D. 5 times
76.
A device that establishes an electrical connection to the earth.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. Grounding conductor
B. Grounded conductor
C. Grounding electrode
D. Grounding electrode conductor
77. A transformer has 4 % resistance and 6 % reactance drop. Find the voltage
regulation at full-load 0.8 p.f. lagging.
A. 6.8 %
B. 5.8 %
C. 4.8 %
D. 160%
Solution:
%R = 4% = 0.04
%X = 6% = 0.06
pf = 0.8, lagging
θ = 36 87˚
)
%VR = √(
%VR = √(
%VR = 6.8%
)
(
[
)
(
)
]
78. A 6-pole, 50 Hz, three-phase induction motor has a maximum torque of 200
N-m when it is running at a speed of 900 rpm. The resistance of the rotor is
0 25 Ω Neglecting stator impedance, determine the torque at 5 % slip.
A. 180 N-m
B. 140 N-m
C. 150 N-m
D. 160 N-m
79. In a certain country, the equivalent fuel reserve for power generation is 3 x
106 MW-yoars. The present peak power demand is 200 GW, and the
expected power consumption growth rate is 2.1 percent. How long will the
fuel reserve last?
A. 8 years
B. 11 years
C. 13 years
D. 14 years
Solution:
F = Pern
3x106 = (200x109)0.021n
n = 13 years
80. Which of the following is not a standard branch circuit among rating?
A. 15 A
B. 25 A
C. 30 A
D. 40 A
81.Once residual magnetism of a shunt generator is lost, it may be restored by
connecting its shunt field.
A. to earth
C. to an external battery
B. in reverse
D. to an alternator
EXPLANATION:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Absolutely it can be restored provided the core material has not suffered
degradation. Excessive heating can do much damage. Re-exciting the
magnetic poles suing a dc exciter (DC power source) can restore the
residual magnetism required for starting. External Battery is a DC power
source.
82.
Power in balance 3-phase system is measured by the two-wattmeter
method and it is found that the ratio of the two-wattmeter readings is 2 is
to 1. What is the power factor of the system?
A. 0.9
B. 0.82
C. 0.866
D. 0.707
SOLUTION:
P1= 1 ; P2= 2 ; pf= cos θ
θ= 30°
p.f. = cos30°
p.f. = 0.866
83.
A coil with 40 ohm resistance and 0.02 H inductance and a pure capacitor
are connected in parallel across a 60 Hz supply. Find the value of the
capacitor in uF if the circuit is resonant.
A. 14.35
B. 12.07
C. 11.67
D. 15.82
SOLUTION:
F= 60 ; R= 40 ; L= 0.02H
Formula of Resonant Frequency:
C = 12.07 uF
84.
A balance delta connected load draws 100 A
line current form a balanced 3-phase supply. Determine the zero
sequence components of the currents.
A. -50 – j86.6
B. 50 – j86.6
C. 86.6 – j50
D. 0
SOLUTION:
(100
85.
)
Iao= 0 = Ibo = Ico
Surge impedance of transmission line is given by:
A √C/L
B √LC
C 1/√LC
SOLUTION:
D √L/
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Upon Simplifying:
Where,
f = Frequency of the system
L = Inductance per unit length of the line
l = Length of the line
Hence we get,
86.
In full-wave rectification, if the in-out frequency is 60 Hz, then output has a
frequency of ______
A. 120 Hz
B. 60 Hz
C. 30 Hz
D. 15 Hz
SOLUTION:
t= t/2
So the frequency,
f= 2f
f= 2(60)
f= 120 Hz
87.
Determine the total inductance of a single-phase overhead transmission
line of 10km long. The diameter of each conductor of 0.8 cm and the
distance between them is 1.2 meters.
A. 11.9 mH
B. 23.8 mH
C. 35.7 mH
D. 47.6 mH
SOLUTION:
( )
(
)(
)(
)
LT = 23.8 mH
88.
A diversity factor of 2 gives a saving of ___ % in generating equipment.
A. 33
B. 50
C. 67
D. 75
SOLUTION:
df = 2
df (saving) = 100%
2 (saving) = 1
saving= 1/2 x 100
saving = 50 %
89.
A room 8 m x 12 m i slighted by 15 lamps wo fairl uniform illumination of
100 lumens per square meter. What is the coefficient of utilization if the
output of each lamp is 1,600 lumens.
A. 40 %
B. 60 %
C. 30 %
D. 50 %
SOLUTION:
100= (x*1600*15) / (8*12)
X= 40%
90.
A 440 -v, 70- HP shunt motor has an ammature of0 185 Ω and field
resistance of 350 Ω The current drawn by this machine is 135 A at fullload. If this machine is to deliver torque equal to 175 percent of that at fullload, what would be the best resistance of its starter?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A 34Ω
B 56Ω
C 22Ω
D
7Ω
SOLUTION:
IST= Vs / (Ra+ RST)
1.75(135) = 440 / (0.185+ RST)
RST = 1.67 ohms
RST = 1.7 ohms
91.
In a parallel Rc circuit, as the capcitance decreases, the power factor
___________.
A. Increases B. decreases C. Remains the same D. Becomes zero
92.
Find the amount of electrical energy expanded in raising the temperature
of 45 liters of water by 75 C. Assume a heater efficiency of 90%.
A. 2.64 KWHR
B. 3.46 KWHR
C. 4.36 KWHR D.6.34 KWHR
SOLUTION:
M= 45L x
m=45kg
Q=45kg x
x 75degree C x
(
)(
)
Q = 4.36KWhr
Answer: C. 4.36 kWhr
93.
A capacitor of 40 μF capacitance in series with 2,000 ohms is suddenly
connected across a 200-volt source. What is the energy stored in the
capacitor after 0.04 sec?
A. 0.124 J
B. 0.241 J
C. 0.412 J
D. 2.41 J
SOLUTION:
Ec=200 (1- e^-t/RC)
Ec=200 (1- e^-.04/(2000)(40x10^-6)
Ec=78.69 V
W = ½ (Ec2/C)
= ½ (Ec2/ C)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
= ½ (78.692/ 40uF)
Answer: B.0.124J
94.
Calculate the average voltage generated in a six-turn full-pitch coil of a 25cycle alternator if the flux pole is 7.2 x 10^5 maxwells.
A. 7.4 V
B. 8.64 V
C. 1.08 V
D. 4.32 V
SOLUTION:
F= 25Hz
= 7.2 x 10^5 maxwells
N= 6
Eave = 4 f N x 10^-8
= (25) (7.2x 10^5) (6) x 10^-8
Eave= 4.32 V
Answer: D. 4.32 V
95.
A 13.8 kV/440 v, 50 kVA single-phase transformer has a leakage
reactance of 300 ohms referred to the 13.8 kV side. Determine the per unit
value of the leakage reactance of the low base.
A. 0.305
B. 0.40
C. 0.097
D. 0.079
SOLUTION:
S= V2/R
= (13800)2/300
= 634800
Per unit= 50000/ 634800
= 0.079
Answer: D. 0.079
96.
A 100 km transmission line has a 1,000 ohms shunt reactance. What is
the per km shunt reactance?
A 1,000 Ω
B
,
Ω
C 10 Ω
D 100 Ω
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SOLUTION:
100 km,
R = 1,000Ω
Rsh = 1000Ω/km 100km
Rsh = 100,000 Ω
Answer: B.
97.
,
Ω
A 5,000 kVA synchronous condenser operates with a leading p.f. of
0.032. The losses are 180 kW.
What is the power input to the motor?
A. 5,160 kW
B. 5,320 kW
C. 160 kW
D. 320 kW
SOLUTION:
Cos ϴ= P/ S
0.032= P/ 5000000
P= 160 KW
Answer: C. 160KW
98.
The current flowing in the armature conductors of a dc motor is
A. ac
B. dc
C. ac as well as dc
D. Transients
99.
The sequence components of phase c current of a 3-phase system are as
follows: Ic0=0, Ic1=18.4 cis88.4, Ic2=3.23 cis48.2. Find the phase b
current in amperes.
A. 19.24 cis -218 B. 18 cis 42 C. 18 cid -42 D. 19.24 cis 218
SOLUTION:
Ia1= (18.4<88.40) (1<120) = 18.4<- 151.6
Ia2= (3.23<48.2) (1<120) = 3.23<168.2
Ib= (18.4<- 151.6)(1<120)+ (3.23<168.2)(1<240)
= 19.23<-22 (1<240)
= 19.23<218
Answer: D. 19.24 cis 218
100.
A current of 20 A is flowing i =n an RL series circuit the instant before the
switch is opened. If R = 10 Ω and L= 10 H, find the current after 3 second
has elapsed.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2016
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 1 A
SOLUTION
I= (E/R)(1- e –R/L(t))
= (200/10)(1-e-10/10(3))
= 19A
I= 20-19
= 1A
Answer: A. 1A
B. 2 A
C. 3 A
D. 4 A
MARCH 2017
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1. A 4 pole lap winding motor with 16 slots, 42 conductors per slot, 480 v runs at 1800
rpm. Find the flux produced per pole.
A. 11.9 mWb
B. 47.6 mWb C. 35.7 mWb
D. 23.8 mWb
SOLUTION:
=
60
=
.
𝒃
2. Compute for the core loss if the transformer consumes 75 watts when it is connected
across a 240 v source and taking 1.4 A. The primary resistance is 0.25 Ω
A. 73.6 W
B. 74.65 W C. 74.75 W
D. 74.51 W
SOLUTION:
=
2
= 1.42(0.25) = 0.49
= 75 − 0 49 =
.
3. What is the total power consumed by the load when the readings of two
wattmeters are 5 kW and -0.5kW?
A. 5.5 kW
B. 4.5 kW
C. 5 kW
D. 4.05 kW
SOLUTION:
W1 = 5kW , W 2 = -0.5kW
PT = W 1 + W 2
=5
−05
= .
4. Find the reactive factor of the load having 30 kW and 50 kVA.
A. 0.6
B. 0.5
C. 0.8
D. 0.7
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SOLUTION:
Q2 = S 2 – P 2
rf = Q
= 40
S
50
Q2 = 502 - 302
= 0.8
Q = 40kVAR
5 Find the total resistance if 3Ω is connected in series with the parallel combination of
4Ω, 5Ω and 20Ω
A 4Ω
B. Ω
C 6Ω
D 7Ω
SOLUTION:
RT = (R1-1 + R2-1 + R3-1)-1 + R4
= (4-1 + 5-1 + 20-1)-1 + 3 =
6. Given a 100 kVA 2,400/240 v single phase transformer. Find the current
transformer (CT) ratio at the low voltage side.
A. 700:5
B. 600:5
C. 500:5
D. 400:5
SOLUTION:
CTR = Ip
Is
Is = S / V
Ans. 500:5
= 100x103 / 240 = 416.67 A
7. One KWHR is equal to __________ BTU.
A. 360
B. 3,413
C. 3,600
SOLUTION:
1kWHR = 3413 BTU = 3600 kJ
8. Convert the delta connected impedance of 12
impedance.
D. 1,000
36 Ω to balanced wye connected
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 3
36°
B. 6
36°
C. 4
36°
D. 12
36°
SOLUTION:
Zwye = Zdelta / 3 = 12cis36 / 3 = 4cis36
9. Heating effect of current has an undesirable side effect in
A. Electric oven
B. immersion heater C. electric iron
D. vacuum cleaner
10. The primary of transformer has 200 turns and is excited by a 240 v, 60 Hz source.
What is the maximum value of the core flux?
A. 4.04 mWb
B. 4.4 mWb C. 4.13 mWb
D.
4.32
mWb
SOLUTION:
= 4.44
240 = 4.44(60)(200)
= .
𝒃
11. When the sole purpose of an alternating current is to produce heat, the selection of
conductor is based on _______ value of the current.
A. average
B. instantaneous
C. root mean square
D.peak
12. What is the primary advantage of FM over AM?
A. FM has a greater bandwidth than AM
B. noise immunity
C. more complex
D. greater capture effect
13. A Walkman has 4 – AA batteries. The combination has a capacity of 200 watt-sec.
How long will it take to discharge if Walkman consumes 10 mA at 6 v?
A. 55.6 min
B.65.6 min
C. 45.6 min
D. 75.6 min
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SOLUTION:
= (10 × 10−3)(6) = 0.06
=
=
= 200 = 3333.33
0.06
×
1
=
=
.
60
14 What is the total resistance of eleven 33 kΩ resistors connected in parallel?
A 33 kΩ
B.
Ω
C 363 kΩ
D 11 kΩ
SOLUTION:
33
=
=
=
11
15. Which of the following is not included in the evaluation of the Technical Performance
of a Distribution System according to Philippine Distribution Code (PDC)?
A. Power Quality
B. Reliability
C. Collecting Efficiency
D. System Efficiency
16. The phase angle for a series RC circuit may be computed as the angle between the
__________ and __________ phasors.
A. resistance, impedance
C. resistance, capacitance
B. resistance, reactance
D. impedance, reactance
17. What is the formula for the synchronous speed of a motor?
A. NN = 120P
B. Ns = 120fP
f
C. Ns = 120f
P
D. Ns = 60f
P
18. Which is not a characteristic of an ideal transformer?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. finite permeability
C. no losses
B. infinite permeability
D. no leakage flux
19.How many 240 v, 20 A branch circuits are required to supply 60,000 va load?
A. 13
B. 14
C. 15
D. 12
SOLUTION:
240 × 20 = 4800
20. Two capacitors in series are changed across 24 v source. If C 1 is 12 picofarads, and
the voltage across it is 6 v, find C2.
A. 6 pF
B. 8 pF
C. 2 pF
D. 4 pF
Solution:
1 = 𝐶 1 +𝐶𝐶22
𝐶2 =
1−𝐶 11 = 6 1224×10−6−12 =
21. It is defined as the total number of sustained Customer power interruption within a
given period divided by the total number of Customers served within the same period.
A. System Average Interruption Frequency Index
B. System Average Interruption Duration Index
C. Customer Average Interruption Frequency Index
D. Customer Average Interruption Duration Index
22. Calculate for the dc voltage when the converter consumes 1.5 kW of power at a
source voltage of 230 v ac.
A. 253 v
B. 352 v
C. 235 v
D. 325 v
SOLUTION:
Vdc = Vac(sqrt. of 2)
= 230(sqrt. of 2)
= 325 v
23. A 115 kV three-phase transposed transmission line is composed of 2-ACSR 336,
400 cmil, 30/7 Oriole conductor per phase with horizontal configuration: D 12 = 7 ft, D23 =
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
7 ft, D13 =14 ft. The line spacing is measured from the center of the bundled conductors.
The distance between the conductors of the bundle is 6 inches. The conductors have a
diameter of 0.741 inch and a GMR of 0.02255 ft. Find the capacitance per phase for 20
km of the line in microfarads.
A. 0.1300
B. 0.2719
C. 0.2889
D. 0.2609
24. The specific resistance ρ is defined as
A. resistance of a conductor which has a length of 1 m and cross-section of
1 m2 at 20°C
B. resistance of any conductor at 25°C
C .resistance of any conductor at 20°C
D. resistance of a conductor which has a length of 1 m and cross-section of 1
cm2 at 20°C
25. The impedance triangle is similar to the __________ triangle with the resistance
phasor in place of the __________.
A. Current, resistor current
C. voltage, impedance
B. Current, resistor voltage
D. voltage, resistor voltage
26. What is the IEEE device function number 50?
A. AC time overcurrent relay
B. instantaneous overcurrent relay
C. AC circuit breaker
D. Differential protective relay
27. In long transmission line, at no-load the receiving end voltage as ccompared to the
sending end voltage is
I. higher
II. lower
III. Remains the same
A. I only
B. II only
C. Either I or II
D. III only
28 How many 100 kΩ will be connected in parallel to obtain 20 kΩ
A. 8
B. 6
C. 5
D. 4
SOLUTION:
Rt = R/n ,
n = R/Rt ,
n = (100k)/(20k)
n=5
29. What determines the direction of force in a conductor?
A. Lenz law
B Faraday’s law
C. Left hand rule
D. Right hand rule
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
30. Which of the following plants will take least time in starting from cold condition to full
load operation?
A. gas turbine
C. nuclear power plant
B. steam power plant
D. hydroelectric power plant
31. The study of illumination involves
A.
B.
C.
D.
design of lighting system
study of lighting and wiring system
calculation of wiring sizes for various lighting fixtures
study of photometry and its application
32. When a power plant is not able to meet the demand of consumers it will resort to
A.
B.
C.
D.
load shedding
efficiency plant operation
power factor improvement at the generators
penalizing high load consumers by increasing the charges of electricity
33. A distributor is designed from the point of view of
A. voltage drop
carrying capacity
B. current carrying capacity
C. voltage drop and current
D. load capacity
34. The annual load curve is a straight line from 40 MW to 8 MW. What is the annual
load factor?
A. 0.8
B. 0.7
C. 0.6
35. Conservator of a transformer consists of
A.
B.
C.
D.
an air-tight metal drum fixed at the top of the tank
drum placed at the bottom of the tank
overload protection
none of these
36. Cellular phones operate in the frequency range of
D. 0.9
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. EHF
B. VHF
C. UHF
D. SHF
37.Varmeter when paired with other devices measures __________ factor?
A. diversity
B. power
C. load
D. demand
38. The type of ac distribution system commonly used to supply both light and power is
the
A. open delta system
C. three phase wye system with neutral wire
B. three phase delta system
D. three phase wye system without neutral wire
39.A 40μF capacitor is supplied with a voltage of v t = 100 sin 377t What is the current
at t=0?
A. 0
B. 1.51 A
C. 3.02 A
D. 1.07 A
SOLUTION:
𝑿 = /𝒘 = /(
= /𝑿 =
)(
/
µ )=
.
= .
.
Ω
40.If an electrical network having one or more than one voltage source is transformed
into equivalent electrical network with a single current source (which is the circuit
current of previous circuit) with parallel internal resistance of the network with all current
source replaced by their internal resistance; the above illustration is called
A. Thevenin’s theorem
C. Reciprocity theorem
B. o ton’s th o m
D. Superposition theorem
41.Which is the most reliable power plant?
A. Steam
B. Hydro
C. Wind
D. Tidal
42.What governs the minimum safety requirement in the Philippines for distribution and
grid?
A. Philippine Electrical Safety Code
C. Philippine Grid Code
B. Philippine Electrical Code
D. Philippine Distribution Code
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
43.In a diode modulator, what supplies the negative halfwave?
A. Inductor
B. Capacitor
C. Resistor
D. Tuned
Circuit
44.Which is not a source of power?
A. Thermocouple
B. Fuel coil
C. Photovoltaic cell D. Solar cell
45. When the frequency of a synchronous motor increases, what happens to its speed?
A. decrease B. increase C. remains the same D. none of these
46. A copper wire is drawn down such that its length is doubled but the volume remains the same,
what is the new resistance of the wire?
A. R1
B. R1/2
C. 2R1
D. 4R1
SOLUTION:
=ƿ
/
=
= ƿ )
= ƿ )(
)/
= ƿ )(
,
ƿ (
)/
/ƿ
)(
=
)/
^
=
47.What instrument measures the insulation of a powerline?
A. growler
B. ohmmeter
C. galvanometer
D. megger
48.What is the frequency where the reactances of 57 μH inductor and a 57 μF capacitor
are equal?
A. 7.92 kHz
B. 9.72 kHz
C. 2.79 kHz
D. 2.97 kHz
SOLUTION:
𝑿
𝝅
^
𝑿
/ 𝝅
/ 𝝅^
√ (𝝅 ) (
)
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
(
.
49 A resistance of 30 Ω and a capacitance of 132 6 μF are connected in series across
a 220 v, variable frequency ac supply. At what frequency in Hz will the current be 4.4 A?
A. 30 Hz
B. 40 Hz
C. 50 Hz
SOLUTION:
𝒁
𝑿
𝑿
= 𝝅(
/ 𝝅
)(
.
− )
=
50. At steady state in an RC circuit, the capacitance will act as __________.
A. open circuit
coupled circuit
B. short circuit
C. transient circuit D.
51. A certain amount of fuel contains 15 x 10 10 BTU of energy. What is the
corresponding energy in kilocalories?
A. 3.78 x 10 13 kcal
B. 3.78 x 10 12 kcal
C. 3.78 x 10 11 kcal
D. 3.78 x 10 10 kcal
SOLUTION:
15×10^10 btu × .252kcal = 3.78×10^10kcal
1btu
D. 60
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
52. In a 3-phase, 4-wire system the current in the a, b, and c lines under
abnormal condition of loading are, I a = 100 30° A, I b = 50 300° A and I c = 30
180° A. Find the zero sequence currents.
A. 18.3 6.81° A
B. 17.3 3.15° A
C. 6.71 5.4° A
D. 27.29 4.69° A
SOLUTION:
Ia=100 &lt;30° Iao=1/3 [ (100 &lt;30°)+(50 &lt;300°)+(30 &lt;180°)]
Ib=50 &lt; 300° Iao= 27.29 4.69° A
Ic= 30 &lt;180°
53. A transmitter supplies 10 kW of carrier power to the antenna. The total
radiated power with 40% modulation is __________ kW.
A. 14
B. 10.8
C. 1.6
D. 25
SOLUTION:
Pt= Pc(1+m^2/2)
Pt= 10 (1+4^2/2) =10.8
54. In a balanced 3-phase voltage source with phase sequence abc, phase A
voltage is 127 cis 0° volts. Find the line C voltage.
A. 127 -240° v
B. 220 -150° v
C. 220 -120° v
D. 127 -60° v
SOLUTION:
Va=127 angle 0° =Va angle;0°
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Va=127 angle -120° =Vb angle -120°
Vc=127 angle 240° =Va angle -240
55. A 6-pole lap wound dc generator has 240 armature conductors, a flux of 0.04
Wb per pole and runs at 1,500 rpm. If the armature resistance is 0 8 Ω, determine the
current through each conductor.
A. 300 A
B. 100 A
C. 50 A
D. 25 A
SOLUTION:
N=6 Pole
Z=240
N=1500
Ra=.8
𝒁ф
𝑬=
(
)(.
)(
)
𝑬=
( )( )
𝑬=
56. An air cored toroidal coil has 450 turns and a mean diameter of 300 mm and
a cross-sectional area of 300 mm 2 . Determine the self-inductance of the coil.
A. 81 x 10 -4 H B. 8.1 x 10 -4 H
C. 0.81 x 10 -4 H D. 0.081 x 10 -4 H
SOLUTION:
N=450 turns A=300×(.001m/1mm)^2= 3×10^-4
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
d=300 mm L= (3×10^-4)(450)^2(4×3.14×10^-7)(1)
A=300mm^2 300×10^-3 (3.14)
L= 0.81 x 10 -4 H
57. A 4-pole, three-phase 50 Hz induction motor develops a maximum torque of
20 N-m at 1,440 rpm. Obtain the torque exerted by the motor at 5% slip.
A. 16.51 N-m
B. 17.51 N-m
C. 18.51 N-m
D. 19.51 N-m
58. A transformer has negligible resistance and a p.u. reactance of 0.1. What is
its voltage regulation on full load with a leading p.f. angle of 30°?
A.-10%
B. 10%
C. 5%
D. -5%
59. In an ac circuit, a low value of KVAR compared with KW indicates
A. maximum load current
B. low efficiency
C. high power factor
D. unity power factor
60. The frequency of the emf in the stator of a 4-poleinduction motor is 60 Hz,
and that in the rotor is 2 Hz. At what speed is the motor running?
A. 1,720 RPM B. 1,740 RPM C. 1,760 RPM D. 1,780 RPM
SOLUTION:
=
/ =
(
)/ =
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
=
=
( )/ =
=
=
61 The voltage across a 50 μF capacitor rises at a constant rate of 10 v/ms Calculate
the current through the capacitor.
A. 50 mA
B. 500 mA
C. 5 mA
D. 5 A
SOLUTION:
I= CE
= (50x10-6)(10)(1/1x10-3)
I= 0.5A or 500mA
62. Branch circuit larger than __________ amperes shall only supply nonlighting outlet load.
A. 15
B. 20
C. 30
D. 50
63.In a 4-pole dynamo, the flux per pole is 15 mWb. Calculate the maximum emf
induced in one of the armature conductors if armature is driven at 600 rpm.
A. 0.6 v
B. 0.3 v
SOLUTION:
E=
𝒁ф
= ( )
(
C. 0.94 v
D. 0.47 v
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
.
.
64. How much larger is the rotor reactance of a SCIM at start-up than it is when the
motor operates at 5 percent slip?
A. 20 times
B. 10 times C. 5 times
D. 25 times
65. The velocity of electromagnetic waves in free space is given by
A.
B.
C. 1/
𝜺
D. √
66. A 220 v, 3-phase, 4-wire abc system supplies unbalanced wye-connected
resistance of 10 Ω, 15 Ω, and 20 Ω Determine the total power of the system in
watts.
A. 3,895
B. 3,560
C. 3,385
Solution:
=
√
)
.
𝒘
D. 3,495
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
67. Assuming a certain driving voltage causes the current to an initially discharged
1,000 μF capacitor to increase at a constant rate of 0 06 A/s , determine the voltage
across the capacity at t = 10 seconds.
A. 600 v
B. 1,500 v
C. 2,000 v
SOLUTION:
E = Q/C
Q = It
=(0.06A/s)(10s)
= .06 C
E=
0.06C
1000x10-6F
E=600
D. 3,000 v
68.The illumination on a surface is 100 lm/m 2. The reflection coefficient of the surface is
80%. What is the maximum brightness of the surface in Cd/m2?
A. 80
B. 125
C. 100
D. 64
SOLUTION:
1lm/m2 = 1cd
0.80x100lm/m2=80lm/m2=80cd/m2
69. Wye-delta starting is equivalent to autotransformer starting with __________
tapping.
A. 33%
B. 58%
C. 85%
D. 52%
70. With reference to armature windings, wave windings are often called __________
windings.
A. cascade
B. ring
C. multiple or parallel
D. series
70. With reference to armature windings, wave windings are often called
__________ windings.
A. cascade
B. ring
C. multiple or parallel
D. series
71. Induced charge on insulators
A. resides on surface
C. changes into electric current
B. moves inside
D. moves outward
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
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PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
72. Human body is
A. Insulator B. low resistive
C. conductor
D. electrolyte
73. The presence of an earth in case of overhead lines
A. increases the capacitance
C. increases the inductance
B. decreases the capacitance
D. decreases the inductance
74. A string insulator has 6 units. The voltage across the bottom most unit is 20%
of the total voltage. Its string efficiency is
A. 20%
B. 60%
C. 75%
D. 83.3%
SOLUTION:
String Efficiency =Operating V(phase)/(nXVoltage nearest to the conductor) x100
String Efficiency = Vph / (6 x .20Vph) x 100 = 83.3%
75. The per unit value of 2 ohm resistor at 100 MVA base and 10 KV base
voltage is
A. 4 pu
B. 2 pu
C. 0.5 pu
D. 0.2 pu
SOLUTION:
Zpu = Zold (Sbase) / (Vbase)^2
Zpu = 2 (100000000) / (10000)^2
Zpu = 2 pu
76. A 75 MW power plant has an average load of 35,000 KW and a load factor of
65%. Find the reserve over peak.
A. 23.41 MW
B. 21.15 MW
C. 25.38 MW
D. 18.75 MW
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
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PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SOLUTION:
LF= Average/Peak
Peak= Average/Load Factor
Peak= 35x10^6/0.65 = 53.846x10^6
Reserve OverPeak= Orig.-Peak = (75x10^)(53.846x10^6) = 21.153x10^6
77. Transformer breaths in when
A. load on it increases
C. load remains constant
B. load on it decreases
D. none of these
78. A hydroelectric generating station is supplied from a reservoir of capacity
6,000,000 m 3 at a head of 170 m. Assume hydraulic efficiency of 80% and electrical
efficiency of 90%. The fall in the reservoir level after a load of 15 MW
has been supplied for 3 hours, if the area of the reservoir is 2.5 km 2 is closest to
A. 5.39 cm
B. 4.32 cm
C. 5.98 cm
D. 4.83 cm
79. The active length of each conductor placed in a DC generator armature is 0.4
m. The armature is related at a speed of 1,800 rpm in a magnetic field of average
flux density 1.2 T. The diameter of the armature is 0.5 m. Find the emf induced in
the conductor when it cuts the magnetic field at right angles.
A. 5.65 v
B. 11.31 v
SOLUTION :
e = βlv sin theta = βlv
C. 45.24 v
D. 22.62 v
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
v = πDN/60 = π 0 5 1800 /60 = 47 12 m/s
e = βlv = 1 2 0 4 47 12 = 22 62 V
80. The flux produced in the air gap between two electromagnetic pole faces 6 x
10 -2 Wb. Length of air gap is 1.4 cm and cross-sectional area of the gap is 0.3 m 2 .
Find the magnetic field intensity.
A. 153.2 x 10 3 AT/m
B. 155. 2 x 10 3 AT/m
C. 157.2 x 10 3 AT/m
D. 159.2 x 10 3 AT/m
81. What is the empirical formula to calculate the number of strands?
A. 3n(n + 2n) + 2
B. 3n(n + 1) + 2
C. 3n(n + 1) + 1
D. 3n(3 + 3n) + 1
82. The shaft of synchronous motor is made of
A. mild steel B. chrome steel C. alnico D. stainless steel
83. For a single line to ground fault, the zero sequence current is given by j3 pu. The
current carried by the neutral during the fault is
A. j1 pu
B. j3 pu
C. j9 pu
D. j6 pu
SOLUTION:
𝒁
𝒁
84. A moving coil instrument requires 50 mA and 100 mV for full-scale deflection.
What is the value of the shunt required to convert it to read up to 5 A?
A 0 0101 Ω
B.
2 2Ω
C 0 0303 Ω
D 0 0404 Ω
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SOLUTION:
( )(
)
85.The resistance of a winding wire made up to copper is 25 ohms at 30°C. What is its
resistance when it operates at a temperature of 75°C? Assume temperature coefficient
at 20°C equals 0.004/°C.
A 31 36 Ω
B 24 04 Ω
C 27 45 Ω
D. 2
Ω
SOLUTION:
(
*
86. Bundled conductors are used in transmission lines, the effective capacitance and
inductance will respectively.
A. decrease and increase
B. increase and decrease
C. remain same and increase
D. decrease and remain same
87. A 40 m metallic conductor of cross-sectional area 1 mm2 has a resistance of 12 Ω
Calculate the conductivity of the metal.
A. 3.33 KS/m
B. 33.3 MS/m
C. 33.3 KS/m
D. 3.33
MS/m
SOLUTION:
(
)(
)(
)
88. A car battery supplies 48 J of energy at 12 v over a certain period of time.
Determine the charge moved during this period.
A. 0.33 C
B. 0.25 C
SOLUTION:
𝑬
𝑬
C. 4 C
D. 2 C
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
89. An inductive coil consumes 500 W of power at 10 A and 110 v and 60 Hz.
Determine the inductance of the coil.
A. 24 mH
B. 25 mH
C. 26 mH
D. 27 mH
SOLUTION:
𝒁
𝑿
√𝒁
√
( )( )( )
√
90. Two coupled coil have self-inductances L1 = 50 mH and L2 = 200 mH, and a
coefficient of coupling K = 0.50. If I1 = 5 sin 400t A, find the voltage at coil 2.
A. 100 cos 400t
B. 100 sin 400t
C. 400 cos 400t
D. 400 sin 400t
SOLUTION:
√
√
(
)
91. In a three-phase system, when the loads are perfectly balanced, the neutral
current is
A. zero
C. two-thirds of maximum
B. one-third of maximum
D. at maximum
92 A parallel RLC circuit has R = 0 5 Ω, L = 10 mH and C = 2.5 mF. Determine
the resonance frequency
A. 63.66 Hz
B. 79.79 Hz
SOLUTION:
Fr= (1/2pi)(sqrt. (1/LC)-(R^2/L^2))
C. 112.82 Hz
D. 31.83 Hz
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Fr= (1/2pi)(sqrt. (1/(10x10^3)(2.5x10^3))-(0.5^2/10x10^2)) = 31.83HZ
93. A double squirrel-cage induction motor has
A. two rotors moving in opposite direction
B. two parallel windings in stator
C. two parallel windings in rotor
D. two series windings in stator
94. A balanced delta connected load draws 10 A of line current and 3 KW at 220
v. Determine the value of resistance of each phase of the load.
A 38 1 Ω
B
Ω
C 23 5 Ω
D 33 3 Ω
SOLUTION:
R= P/ I^2= 3000W/ 10^2= 30 OHM
95. Three sinusoidal generators and a battery are connected in series with a coil
whose resistance and inductance are 8 Ω and 26 53 mH, respectively The
frequency and rms voltage of the respective generators are 20 Hz, 15 v, 60 Hz,
30 v, 80 Hz, 50 v. The battery voltage is 6 v. Determine the circuit rms voltage.
A. 10 v
B. 60.51 v
C. 101 v
D. 69.5 v
96. A 12 KVA load A operating at 0.70 p.f. lagging and a 10 KVA load B
operating at 0.80 p.f. lagging are connected in parallel and supplied by a 440 v,
60 Hz generator. Determine the system power factor.
A. 0.767
B. 0.727
C. 0.747
D. 0.787
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
SOLUTION:
I= S/ V= 12000KVA /440V= 27.27angle 45.57
I= S/V = 10000KVA/ 440V= 22.73angle 36.87
It=I+ I= (27.27angle 45.57)+(22.73angle 36.87)= 49.86angle 41.618
arcos(41.617)= 0.747
97. Suppose that the consumption of energy in a certain country has a growth
rate of percent per year. In how many years will the energy consumption be
tripled?
A. 20.60
B. 13.73
C. 9.16
D. 27.47
98 A 345 KV transmission line has a series impedance 4
j60 Ω and a shunt
admittance of j2 x 10 -3 S. Using 100 MVA and the line voltage as base values,
calculate the per unit shunt admittance of the line.
A. j2.38 pu B. j3.57 pu
C. j4.76 pu
D. j5.95 pu
SOLUTION:
Z= 1/Y= 1/j2x10-3= -j500
Zpu= (j500x100x10^6)/(345x10^3)= j0.42
Ypu= 1/ Zpu= 1/j0.42= j2.38 pu
99. The purpose of providing dummy coils in a generator is
A. to reduce eddy current losses C. to amplify voltage
B. to enhance flux density
C. to amplify voltage
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
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D. to provide mechanical balance for the rotor
100. The conductors of a three-phase transmission line are arranged in the form
of an equilateral triangle with sides of 6 m each. If the conductors are 500 mils in
diameter and the line is 25 km long, what is its inductance per phase?
A. 40 mH
B. 17.75 mH
C. 26.62 mH
D.
35.5
mH
AUGUST 2017
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1. A conductor of length 1 meter moves at right angle to a magnetic field of flux density
1 Wb/m^2 with a velocity of 25m/s. What is the induced emf in the conductor?
Solution:
e= wsinᴓ
=25(1)(1)
=25V
Answer: A. 25v
2. It is difficult to magnetize steel because of its
Answer: C. Low Permiability
3. Present day capacitors which have high capacitance in small size use a dielectric of
Answer: C. Ceramic
4. The current-carrying capacity of a copper wire having twice the diameter of another
copper wire is ______________ as great.
Solution:
.
Therefore,
=
=
=4
Answer: B. Four times
5.The output current corresponding to maximum efficiency for a transformer having
core loss of 100 watts and equivalent resistance referred to secondary of 0 25Ω is
________ amperes
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
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PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Solution:
Pco = Pcu
100=
I=
√
= 20A
Answer: B.20
6. What kind of device is a diode?
Answer: D. Nonlinear
7. What is the value of inductance of a coil that induces 100v when the current changes
at the rate of 2mA in 2 microseconds?
Solution:
e= L
=L
L = 0.1H
Answer: D. 0.1H
8. In a generator, if the voltage regulation is 5.5% and the full-load voltage is 220 volts,
what is the no-load voltage equal to?
Solution:
(
=
=
(
)
)
= 232.1
Answer: A. 232.8v
9. If the line frequency is 60Hz, the output frequency of a bridge rectifier is
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
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PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Answer: C. 120Hz
10. At what frequency will a 100µF capacitor offer a reactance of 100Ω
Solution:
C=
100 =
(
)
= 15.9 Hz
Answer: B. 15.9 Hz
11. A 4-pole wave wound generator has 220 coils of 10 turns each. The resistance of
each turn is 0 02Ω find the resistance of armature winding
Solution:
(
Answer: A.
=
)
Ω
Ω
12. A three-phase 4-pole 60Hz induction motor has a rotor resistance of 0 02Ω/phase
and stands still reactance 0f 0 5Ω/phase Calculate the speed at which the
maximum torque is developed.
Solution:
%slip=
=
= 0.004
Nr= Ns(1-%slip)
=
=
(1-%slip)
(
)
(1-0.004)
Nr = 1728 RPM
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
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PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Answer: D. 1728 rpm
13. In a shunt generator the voltage builds up till constrained by
Answer: C. Saturation of iron
14. Slip rings are made of
Answer: B. copper
15. How much energy is stored by a 100mH inductance with a current of 1A?.
Solution:
W= ½ (100 x
)(1)
W = 0.05J
Answer: B. 0.05J
16. For proper parallel operation, ac polyphaser alternators must have the same______
Answer: C. Voltage Rating
17.Suppose that the consumption of energy in a certain country has a growth rate of
4% per year. In how many years will the energy consumption be tripled?
Solution:
Q = Qo
3Q = Qo
ln 3 = ln
t= 29.47
Answer: B. 29.47
18. The capacitance between any two conductors of a three-conductor cable, with the
third conductor grounded is 0.6µF/km. Calculate the line to ground capacitance of a
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
25-km length of the cable.
Solution:
C= (0.6
) (25km) = 15
)
CT = 2 (15
CT = 30
Answer: A. 30µF
19. A transmitter supplies 10kW of carrier power to the antenna. The total radiated
power with 40% modulation is ________ kW
Solution:
Pr= Pc (1 +
= 10 (1+
)
)
Pr = 10.8 kW
Answer: D. 10.8
20. A 3-phase, 4-pole induction motor with the open circuited rotor is connected to a
400-v, 50Hz, 3-phase supply. The motor will run at _________rpm.
Answer: D. 0
21. A lamp has a luminous efficiency of 11 lm/watt and gives out a luminous flux of 275
lm. What is the wattage of the lamp?
Solution:
P=
P = 25 W
Answer: B. 25
22. The series field of a short-shunt compound dc generator is excited by ______
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
current.
Answer: D. External
23.If copper loss of a transformer at 7/8th of full load is 4900W, then what is its full-load
copper loss?
Solution:
= size x
=( )
P =6400W
Answer: B. 6400 W
24.The Reciprocal of permeability is
Answer: C. reluctivity
25. For which of the following sinusoids, the rms value and mean value is the same?
Answer: C. Square Wave
26.A 440-v; three-phase source supplies a wye connected 10KVA load at 0.8 lagging
power factor and a delta-connected 10KVA unity power factor load. Calculate the
total apparent power input to the two loads.
Solution:
= 10 cis –
(0.8) +10
= 18.97KVA
Answer: D. 18.97KVA
27. The maximum efficiency of a half –wave rectifier is
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
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PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Solution:
=(
)x 100
 = 40.5%
Answer: A. 40.6%
28. A resistance of 30 ohms and a capacitance of 132.6µF are connected in series
across a 220v variable frequency ac supply. At what frequency in HZ will the current
be 4.4A?
Solution:
Z=
=
= 50
=
+
)
= (√
= 40 =
=
(
)(
f = 30 Hz
Answer: D. 30 Hz
29.A balanced wye-connected load with resistance of 8ohms/phase and no reactance
is supplied by a 240v, 3-phase source. Find the real power of the load in watts.
Solution:
V= IR
I=30
P=
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
( )
=
P= 7200 W
Answer: B. 7200
30. Given three unbalanced line currents Ia=0+j12A, Ib=5-j10A and Ic=-10-j5A. Find the
negative sequence component of Ic in amperes.
Solution:
=
[
+
+a ]
= 2.25 cis 105.70
= 2.25cis 105.70 (1cis240)
= 2.25 cis -14.3
Answer: C. 2.25cis-14.3deg
31.A 40ohm resistor and a pure capacitor are connected in parallel across a 230v,
60Hz ac supply. The total current taken from the supply is 8A. Find the capacitance
of the capacitor in µF.
Solution:
Z = V/I = 230/8 = 28.75
Z= 28.75 =
(
)
Trial and error substitute the given to find Z = 28.75
Therefore, 64.15µF
Answer: A. 64.15µF
32. Two electrons in a vacuum experience a force of 2 x 10^-15 N. How far apart are
the electrons?
Solution:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
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PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
P= kQ1Q2 / d^2
=
=
K=
d=
√(
)(
)
d= 3.4 x 10^-7 m
Answer: A. 3.4 x 10^-7m
33.A 120 volts battery having an internal resistance of 0 5Ω is connected through line
resistance of 9 5Ω to a variable load resistor What maximum power will the battery
deliver to the load resistor?
Solution:
P=
=
(
)
P = 360W
Answer: D. 360 W
34. Three resistors of 10Ω, 15Ω and 20Ω are connected in parallel What is the total
resistance?
Solution:
= [
+
+
] ^ -1
4 2Ω
Answer: B. 4 2Ω
35. 10^13 ergs/sec is equal to how many KW?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Solution:
=1000KW
Answer: A. 1000 KW
36. Ideal transformer assumptions do not include
Answer: D. zero reactance of the winding
37.A dc ammeter has an internal resistance of 0 1Ω A shunt 1 01 x 10^-3Ω is
connected to the ammeter. What is the multiplier of the set up?
Solution:
R = 0 1Ω
R=
= 100 Ω
Answer: C. 100
38. Two conductors carrying 50 amperes and 75 amperes respectively are placed 10cm
apart. Calculate the force between them per meter
Solution:
F= (
)(
F=(
)(
)
)( )
F=
Answer: C. 0.0075N/m
39. A three-phase motor is rated 50HP, 440 volts and 85% power factor. What is its
rated current?
Solution:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
P= √3 VL IL pf
I=
; P= 50HP x
√
=
√ (
)(
)
I = 57.5A
Answer: B. 57.5A
40.A 100-km transmission line has 1200Ω shunt reactance What is the per km shunt
reactance?
Solution:
Unit Analysis
= (1,200)(100)
= 120,000
Answer: B. 120,
Ω
41. Two 500-watt lamps connected in series across a 220-volt line draw 1A. What is the
total power consumed?
Solution:
P= IV
= 1 (220)
P = 220w
Answer: B. 220w
42. A switch is connected across a 220v supply. What is the voltage across the switch
if it is opened?
Answer: C. 220v
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
43. Calculate the AT/m to produce a flux density of 0.001 Wb/m^2 at the center of a
long straight solenoid.
Solution:
µ = 4pi x
β = µH
H=
= 795.77
796
Answer: D. 796
44. A series RLC circuit consists of 20 ohms resistance ,0.2H inductance and an
unknown capacitance if the circuit has a leading angle of 45% at 60Hz/
Solution:
tanᴓ =
20=
= 2 fL – 20 =
C=
(
)
==
(
)(
)(
)(
= 47.9 µF
)
Answer: B. 47.9µF
45.A circuit which has wo= 10^6 rad/sec, C= 10pf and Q=100, must have a resistance
of ____kΩ
Solution:
f=
√
; Q=
√
√LC =
√ 𝐶 =
L=
=(
)(
)
= 0.1
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
R=
=
√
√
Ω
Answer: C. 1
46.A coil of copper wire has a resistance a 5 46Ω at 75deg C What will be its
resistance at 25deg C.
Solution:
Copper = 234.5 [T(C)]
=
=4
(
)
(
)
Ω
Answer: D. 4.58 Ω
47.A coil of 50Ω resistance and 150m H inductance is connected in parallel with a 50µF
capacitor. The source voltage is 100 sin (wt + 30deg) v. What is the equation of the
line current?
Solution:
Hz
(
(
)(
)
(
)(
)
)(
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Answer: C. 1.25 sin (wt + 75.5deg)
48. A lead-acid battery having a 100Ah capacity is 25% charged. After being charged at
10A for 5hours, It will be approximately _________ charged.
Solution:
( )
(
)
Answer: B. 3/4
49.The current in a coil decays as follows; when t=0.002 sec, the current is 10 mA ;
when t=0.006 sec, the current drops to 4 mA. The time constant of the coil is
_______
Solution:
0.01= Io
Io =
0.01
=
= 0.004
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
ln
= ln
= ln (0.4) –
Tc = 4.36 ms
Answer: B. 4.36 ms
50. If the load current and flux of a dc motor are held constant voltage applied across its
armature is increased by 10%, its speed will ________________.
Answer: C. increase by about 10%
51.An abc phase sequence three phase voltage source connected in a balanced wye
has a line voltage of Vab= 208cis0° v rms. Determine the phase voltage Vbn.
Solution:
Vab = 208cis0
Vbc = 208cis-120
VL lags Vᴓ by 30°
Vbn = Vbc/√ cis30
= 208/√ cis30
= 120cis- 150
Answer: C. 120cis-150°v
52. A 15-hp motor operates at an efficiency of 87.5 percent at full-load. If the stray
power loss is approximately one-fourth of the total loss, calculate the copper loss.
Solution:
Pi = Pcu + SPL + Po
TL = Pcu + SPL
Pi = TL + Po
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
TL = Pi - Po = 1598.57
SPL = TL
therefore: Pcu = TL = ( 1598.57)
Pcu
1200 W
Answer: A. 1,200 W
53.A 4-pole shunt motor develops 20 lb-ftcf torque when the flux per pole is 700,000
maxwells. If the armature winding has 264 conductors and is wound wave, calculate
the total armature current.
Solution:
T=
= 9.55
N-m = 7.04
lb ft
1 N-m=
Ia =
(
)(
(
)(
)(
)
)
Ia = 46.12A
Answer: C. 46 A
54. A dc shunt motor has a nameplate rating of 15HP, 230 v, 57.1 amperes, and 1,400
rpm The field circuit has a resistance of 115
0 13
and the armature circuit resistance is
Neglecting the effect if armature reaction, find the on-load line current.
Solution:
Shunt Motor:
Ic = Ia + If
If = 230/115 = 2A
Eb = V2- IaRa
= 230 – 55.1(0.13) = 222.837
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Ia = 57.1 – 2
Pd = EaIa
= 55.1A
= 12,278.32W
Po = 15 x 746 = 11,190W
Pin =Pd – Po = 1088.3187 W
Pm = EbIa
Pm = [ 230 – IaRa] [Ianl] ^2
1088.32 = 230Ianl -0.13Ianl^2
Ianl^2 -1769.23Ianl + 8371.64 = 0
Ianl1 = 1764. 48546 – Too High
Ianl2 = 4.74 – useful
Ilnl = Ianl + If
= 4.74 + 2 = 6.74A
Answer: C. 6.74 A
55. A capacitor of 0.1µF capacitance charged to a potential difference between plates of
100 v, Is discharged through a resistor of 1 megaohm. Calculate the initial value of
decay of capacitor voltage.
Solution:
Answer:
56.A 400-volt 50Hz star connected induction motor takes a line current of 50 amperes
at a p.f. of 0.8 lagging. Three mess connected capacitors are connected pf raise the
p.f. to 0.9. Find the value of each capacitor in microfarads.
Solution:
Q = P (Tan
- Tan
)
P = √ VL IL pf = √ (400)(50)(0.8)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
= 27,712.8 W
=36.87
25.84
Q = 27,712.8 [ Tan36.87 – Tan 25.84]
= 7362.68VAR
Q/3=
Xc =
2 fC
C = 7362.68 / 3(400)^2 (2pi)(50) = 48.9µF
Answer: B. 48.9
57. Two transformers are connected on open delta and deliver a balanced three-phase
load of 245 kW at 460 volts and power factor of 0.707. Calculate the power
delivered by the individual transformers
Solution:
=
= 346534.65
= 200071.88 =
√
= cos-1 (.707) = 450°
cos-1 ( 45 + 30 )= 0.2588
= cos-1 ( 30 - 45 ) = 0.966
=S
=S
= 193.2 KW
= 51.8 KW
Answer: B. 193.2 kW, 51.8 kW
58.A 500 volts 1 Φ synchronous motor is taking 50 amperes at a p f of 0 8 leading The
output is 25 HP and the effective resistance of the armature is 0.25 ohm. Find the
iron and firction losses.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Solution:
Pin = PL + Po ; PL = Pin – Po
PL = 500 (50)(0.8) – 25 (746)
= 20,000 – 18,650
= 1350
PL = Pcu + Pco
Pcu =
=
(0.25)
= 625
Pco = PL-Pcu
= 1350 – 625
= 725 W
Answer: D. 725 W
59. A two-pole three-phase 50 Hz star connected ac generator has 9 slots/pole and 6
conductors/slot. What is the flux per pole if the terminal voltage of open circuit is
1,100 volts. Take the coil span as unity.
Solution:
=
=
= 20 deg
 = slots per pole per phase
=
d=

=3
(
=
)
= 0.959
kp = sin (90 x pitch ) = sin (90 x1 ) = 1
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Z=
= 36
Ep = 2.22kpdf Z
√
( )(
)(
)(
)
0.1756 Wb
Answer: A. 01756 Wb
60. A 500-KVA alternator operates at 80% of full-load with an efficiency of 92 percent. If
the load power factor is 0.8, calculate the total loss.
Solution:
 = Po / Po + PL
PL =  - Po =
(
)(
)(
)
– 0.8 (500x
)(0.8)
PL = 27,826
PL = 27.83 KW
Answer: A. 27.83 kW
61. If there is an open circuit in the rotor of a JCIM,
Answer: C. motor will not start
62. In a synchronous machine when the rotor speed becomes more than the
synchronous speed during hunting, the damping bars develop______ torque.
Answer: C. induction generator
63.A 20 KV/7, 87KV auto transformer has a secondary line current of 100 A. What is
the current in the common winding?
Solution:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
=
=
=
x= 39.35
Icw = 100- 39.35
Icw = 60.65 A
Answer: B. 60.65 A
64. A 3Φ, 6-pole, 50 Hz induction motor develops 3.73 KW at 960 rpm. What will be the
stator input if the stator loss is 200 watts?
Solution:
Pd = 3.73 kw
Nr = 960
Ns =
(
)
= 1000
SPI = SCL + RPI
RPI = RCL + RPD =
RDD =
(
) = RPI (1-s)
RPI =
SPI =
=4165.4W
Answer: D. 4,165 W
65. A three –phase, wye-connected, 6.25 kVA, 220-volt synchronous generator has a
reactance of 8.4 ohms per phase. Using the rated kVA and voltage as base value,
determine the per unit reactance.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Solution:
=
=
(
√ (
)
= .626
Answer: D. 0.627
66.A two-pole alternator is running at 1,500 rpm, what is the angular velocity?
Solution:
1550
x
x
= 157.1
Answer: C. 157.1 rad /sec
67. At leading p.f., the armature fkux in an alternator________ the rotor flux.
Answer: C. opposes
68. Synchronous motors are
Answer: B. not self-staring
69.A three-phase induction motor is taking 40kWm the slip being 4% and stator losses
amount to 800 watts, Calculate the total power developed.
Solution:
SPI = 40kW
S = 0.04
SCL = 800
RPI = SPI – SCL =39,201
RPD = RPI (1-s)
RPD = 37,632W
Answer: A. 37.63 kW
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
70.The per-unit reactance of a synchronous generator are <d = 1.1, Xd^i = 0.24, Xd^a
= 0.15. The Generator is operating without load at 5 percent above rated voltage
when a three-phase short circuit occurs at its terminals. What is the per unit
subtranient fault current?
Solution:
Answer:
71.Three 30.1 step-down transformers are connected Y -
for stepping down the
132,000-volt three-phase transmission voltage. Calculate the secondary line
voltage.
Solution:
√
=a
Vs =
√ (
)
Vs = 7,621v
Answer: C. 7,621 v
72.A hydroelectric generating station is supplied form a reservoir of capacity 5 x 10^8
m^3 at a head of 200 meters. Find the total energy available in KWHR if the overall
efficiency is 75%
Solution:
 = Po / PN20 x 100
Po = PN20 = 0.75 (2.75x10^6 kWHr) = 2.044x10^6 kWHr
PN20 = QWH
=(
)(9810 N/m^3) (200m)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
=(
=
) N-m x
kWHr
Answer: B. 2.044x10^6kWHr
73. This is the rating of power circuit breakers used to be the basis in replacing its
contacts.
Answer: C. Duty Rating
74.A uniform source of light gives 1,884 lumens and is suspended 4 m above the
center of floor 3 m square, Find the illumination in lm/m^2 at the floor level directly
below the lamp.
Solution:
E = I / s^2
I=
E=
=
= 150
= 9.41lm/
Answer: A. 9.4
75.An amplifier has an output of 50 watts. What is its output in dBm?
Solution:
dBm=
=
= 47dBm
Answer: A. 47dBm
76. A consumer requires 2 x 10 ^6 KWHR per year and its yearly load factor is 30
percent. What is its maximum demand?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Solution:
MD =
=
(
)
(
)
(
)
= 761 kW
Answer: D. 761 kW
77.If a half-wave rectifier is used 117-v rms ac (house mains), the average dc output
voltage is about ;
Solution:
√ (
) = 165.46
= 0.318 (165.46)
=52.67V
Answer: A. 52.7 V
78. A short 3Ø transmission line with an impedance of 6 j8
per phase has
sending and receiving end voltages of 120 kv and 110 kv respectively for some
receiving end load of a p.f of 0.9 lagging. Determine the sending end power factor.
Solution:
R= 6 Ω
XL = 8 Ω
P.f = 0.9
ƟR = cos-1 0.9 = 0.451
VS =
√
= 69.28 Kv
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
VR =
= 63.51 Kv
√
VS = VR + I (R Cos ƟR
XL Sin ƟR )
69.28 = 63.51 + I ( 6 X 0.9 + 8 X Sin 0.451)
I = 650. 3 A
Sending end P.f = (VR Cos ƟR + IR)/ VS
=
(
)(
) (
)( )
= 0.88 Lag
Answer: A. 0.88 lag
79. A generating plant has a minimum and maximum outputs of 50 MW and 100 MW,
respectively. It generates an energy of 1,800,000 KWHR for 24 hours at average
power factor of 90%. What is the load factor of the plant?.
Solution:
Max Demand (MD) = 100 MW
Total Energy Produced (TEP) = 1,800,000 KWHr
Hours of Service (SH) = 24 Hours
LF =
(
)(
)
LF = 75 %
Answer: A. 75 %
80. A 75 MW steam power station uses coal of calorific value of 6,400 kcal/kg. Thermal
efficiency of the station is 30% while electrical efficiency is 80%. Calculate the coal
consumption per hour when the station is delivering its full output.
Solution:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
noverall = nthermal x nelectrical
= 0.3 x 0.8
= 0.24
Units generated per hour : @ 1 KWHr = 860 Kcal
(75 x 10 3 ) x 1 = 75000 KWHr
Heat Produce / Hour = Electrical Output in Heat Units / noverall
(
)
Coal Consumption / hour =
𝐶
𝐶
= 41,992 Kg x
= 42 tons
Answer: D. 42 Tons
81. An air core toroidal coil has a 120 turns and the length is 12 cm. What is the current
required to set up a flux of 1.2 x 10^5 weber? If the cross-sectional area is 12
square cm?
Solution:
Φ=
(
Answer: B. 0.7960 A
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
82.A shunt motor with an armature resistance of 0.15 ohm is running 1,200 rpm for a
load which requires an armature current of 50 A form a 230 v source. At no load, the
armature current is 5 A. If the effect of armature reaction has reduced the air-gap
2% form no load to full load, what is the no load speed?
Solution:
Answer:
83. A 60 KV, three-phase short transmission line is 16 km long. The line has a per
phase series impedance of 0.125 + j0.4375 ohm per km. Determine the
transmission efficiency when the line delivers 70 MVA, 0.80 lagging power factor at
64 KV.
Solution:
Answer:
84. A copper conductor with a diameter of 0.10 inch has a resistance of 1 ohm per
1,000 ft. What is the resistance of 200 ft copper wire with a diameter of 40 mils?
Solution:
d1 = 0.10 in
d2 = 40 mils x
(
*
(
)
2
nsw :
= 0.04 in
2 Ω
2 Ω
85. A three-phase 60 HZ transposed 230 KV transmission line has a horizontal
configuration of Dab = D and Dbc = D and Dac = 2D. The line reactance is 0.486
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
ohm per km. The conductor GMR is 2.0 cm. What is the phase spacing D?
Solution:
Answer:
86. A straight conductor 100 cm long and carrying 40 A lies perpendicular to a magnetic
field of 1.5 T (Wb/sq.m). What is the mechanical power in watts required to move
the conductor at a uniform speed of 5 meters per second?
Solution:
e=βlv
= 1.5 X 100
X5
= 7.5 V
P = e x I = 7.5 x 40
P = 300 W
Answer: D. 300 W
87. A 9.6 KW, 240 volts shunt generator having an armature resistance of 0.10 ohm and
a shunt field resistance of 240 ohms, delivers full load at rated voltage and 800 rpm.
The machine is now run as a motor while taking 250 v. Neglect the brush contact
drop, what is the speed of the motor?
Solution:
Answer:
88. A single-phase, 10-km transmission line has a 16.65 mH total inductance. If the
distance between the conductors is 1.0 m, what is the conductor radius?
Solution:
Answer:
89. A room measuring 16 m is to be illuminated by 8 lamps with an average illumination
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
of 72 lm/sq. m at floor level. If 40 percent of the total light emitted is absorbed by the
walls and ceiling, calculate the mean spherical candle power required for each lamp.
Solution:
Answer:
90. A 3-phase circuit 60 HZ, 230 kV transposed transmission line composed of two
1,272 MCM 54/19 conductors per phase with horizontal configuration. The bundle
conductors are 50 cm, In distance while phase spacing between the centers of the
bundle is 10 meters. If the GMR of the ACSR conductors is 0.0466 ft, find the
inductive reactance on ohm/km/phase of the transmission line?
Solution:
Answer:
91. The voltage applied across the resistor was reduced by 50%. The power consumed
by the resistor will be reduced by ________%.
Solution:
Therefore
( )
Answer: C. 25
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
92. A balanced delta connected load of 4 – j3 per phase is fed by 380 v, 3 – phase
system. Find the reactive power in VAR.
Solution:
*(
(
)
Answer: A. 52 KVAR
93. The effect of the dielectric is to
Answer: D. reduce the working voltage
94. A transmission line cable consists of 26 strands of identical copper conductor, each
1,255 mm in diameter. The length of the cable is 10km, but because of the twist of
the strands, the actual length of each conductor is increased by 5%. If the resistivity
of the copper is 1.72 x 10 raised to -8 ohm/meter, what is the resistance of the
cable in ohms?
Solution:
(
)(
)(
(
)
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Answer: D. 5.62
95. Two lamps having luminous intensity of 250 and 300 candelas, respectively are
placed 100 m apart. Lamp A is placed 10 m above the ground while lamp B is
placed 20 m above the same level. What is the illumination at the center of the lamp
posts at ground level?
Solution:
Answer:
96. A short 230 kV transmission line has an impedance of 10 cis 80
The sending end
powers 150 MW at 230 kV and 82% power factor. What is the voltage at the other
end?
Solution:
Z = 5√
P = VL IL Cos Ɵ
P.f = 0.82
150 x
Ɵ = 34.415
IL = 795 A
IL (0.82)
Sin Ɵ = 0 572
VS2 = (VR + IL Cos ƟR
IX Sin ƟR)2
IX Cos ƟR – IL ƟR)2
VR = 227 KV
Answer: D. 225.45 KV
97. In a short circuit study, the positive, negative and zero sequence impedances are
0.25p.u., 0.25 p.u. and 0.3 p.u., respectively. The base MVA is 100. Determine the
fault current for a three phase fault at the 115 kV level.
Solution:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
3 Phase Fault
√
(
)
√ (
)
(
)
Answer: A. 3000 A
98. Two single phase transformers each rated 75 kVA are connected in V or open-delta
to serve a three-phase load of 120 kW at 0.80 power factor lagging. To prevent the
overloading of transformers, determine the size of the capacitor in kVAR.
Solution:
Answer:
99. A 1 5 M
resistor is connected in series with a 20 µF capacitor. The voltage source
is 120 volts dc. Determine the time at which the voltage across the capacitor is 75%
of the source voltage.
Solution:
Vc = E (1 -
) ; RC = 30
shift solve: t = 41.58 sec
≃ 41.60 sec
Answer:A. 41.6 sec
100.An induction motor with 8 poles, 60 Hz is operated with a slip of 3%. Calculate the
rotor speed.
Solution:
P=
=
(
)
;
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2017
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
%S =
0.03 =
P = 873
Answer: C. 873
MARCH 2018
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1. In Delta connected circuit, when one resistor is open, then power will be
A. 0
B. increased by a factor of 3
C. decreased by a factor of 3
D. remain unchanged
2. Which does not belong
A. lines per square centimeter
B. maxwells per square centimeter
C. flux
D. gauss
3. The diameter of a conductor is 0.064 inch. What is the area in circular mils?
A. 5,000
B. 10,000
C. 3,217
D. 4,096
Solution:
d=0.064inch
d= 0.064inch (1000mils/1inch) = 64mils
A = d² = 64² = 4096 CM
4. In a shunt motor, what is the relative connection of the armature winding with
respect to the field winding?
A series
B. parallel-series
C. series-parallel D. parallel
5. A series RLC circuit has R = 10 ohms , L = 40 x 10^-6 H and C = 60 x 10^-12
F. What is the resonant frequency of the circuit in MHZ?
A. 20.17
B. 3.24
C. 4.49
D 1.62
Solution:
R= 10 ohms
L= 40 x 10^-6 H
C= 60 x 10^-12 F
√ 𝐶
√(
)(
)
𝒁
6. A capacitor charged with 10,000 uC. If the energy stored is 1 joule, find the
capacitance.
A 500 uF
B. 5 uF
C. 5,000 uF
D. 50 Uf
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Solution:
Q= 10000 uC
W= 1 J
C=?
W = ½ Q^2 / C
C = ½ Q^2 / W = ½ (10000x10^-6)² / 1 = 50 x 10^-6 F or 50 uF
7. A 440-volt synchronous motor is taking 50 amperes at a pf of 0.9 lagging. The
effective resistance of armature is 0.8 ohm. If the iron and friction losses amount
to 600 watts, find the horsepower output.
A 25.7
В 37 1
C. 23.1
D. 40.5
Solution:
VL= 440v
IL= 50A
PF= 0.9
Ra= 0.8 ohms
Pfw= 600W
Pi = √3 VL IL PF = √3 440 50 0 9 =34 3 KW
Pcus= IL²Ra = 50²(0.8) =2000 W
Pout = 32.3 KW – 2000 W – 600 W = 31.7 KW ÷ 746 = 42.5 HP
8. What is considered as the most important value of a sine wave?
A. Effective value
C. Average value
B. Peak value
D. Instantaneous value
9. For a 3-phase load balanced condition, each phase has the same value of _
A. impedance
B. resistance
C. power factor
D. all of these
10. Three 100 uF capacitors are connected in delta to a 500-volt, three-phase, 50
Hz supply. Find the line current.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A 15.71 A
B. 27.21 A
C. 31.83 A
D 8.66 A
Solution:
C= 100pF
VL= 500v, 50Hz
IL=?
Xc= 1/ 2πfC = 1/ 2π(50)(100uF)= 31.8
Iphase= 500/31.8 = 15.72A
IL= √3 Iphase = √3 15 72 = 27.23 A
11. Assuming the most efficient technologies for the extraction of energy, the fuel
with the largest known reserves is
A. Coal
B. Oil
C. Natural gas
D. Nuclear
12. A three-phase 60 Hz line has flat horizontal spacing. The conductors have an
outside diameter of 3.28 cm with 12 m between conductors. Determine the
capacitive reactance of the line to neutral if its length is 125 miles.
^ Ω
.
B. 202.4 x 10^3 Ω
C. 25.3 x 10^3 Ω
D. 16.2 x 10^3 Ω
Solution:
Given : f = 60 Hz, D = 12m, d = 3.28 = .0328, r = .0164m
L = 125mi = 201.168 km
C = 8.138x10-12 F/m ( 1000m/ km )(201.168 km)
C = 1.637x10-6 F
Xc = 1/wC = 1/ 2πx60x1 637x10-6) = 1.6x103 Ω
13. A circuit has a resistance of 20 ohms and reactance of 30 ohms. What is the
p.f of the circuit ?
A. 0
B. 0.55
Solution:
Given: R = 20, X = 30
Z = R + jX
C. 0.832
D. 0.99
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Z = 20
j30 = 36 06∟56 31˚
Pf = cos(56.31) = 0.55
14. A capacitive load always has a __________ power factor
A. Leading
B. Lagging
C. Zero
D. Unity
15. A road is illuminated by two 500 candela lamps place 6.1 m above the center
line of the road and 18.3 m apart. Find the illumination produced on the surface
of the road at a point on the center line midway between lamps
A. 2.29 lux
B. 4.58 lux
C. 9.16 lux
D. 18.32 lux
Solution:
Given: I = 500
h1 = h2 = 6.1m, d = 18.3/2 m = 9.15 m
d2 = 6.12 + 9.152= 120.93
tanƟ = 9 15/ 6 1, Ɵ = 56 31
Ep 1= (I/d2 cosƟ
Ep1 =(500/120.93)cos(56.31) = 2.29 = Ep2
Eptotal = Ep1 + Ep2 = 2.29 + 2.29 = 4.58 lux
16. A magnetizing force of 1000 AT/m will produce a flux density of ___________
in air
A. 1.257 mWb/m^2 B. 0.63 mWb/m^2 C. 1.257 Wb/m^2 D. 0.63 Wb/m^2
Solution:
Given: H = 1000 AT/m
ᵦ = H x uo = 1000 4πx10-7) = 1.257x10-3 mWb/m^2
17. In hydro electric power plant, it is use to prevent the sudden rise and drop of
water pressure.
A. Penstock
B. Intake tower
C. Dam
D. Surge tank
18. The basis where the flow of current is from positive to negative was derived
from __________
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. Superstition
B. Tradition
C. Scientific
D. Convention
19. The following are the given loads of a particular circuit
5 - 15 HP motors
3 - 5 HP motors
8 KW - lighting loads
3.5 KW - miscellaneous loads
Calculate for the maximum demand if the demand factor is 65%
A. 78.64
B. 45.81
C. 51.12
D. 120.28
Solution:
Given : 5 - 15 HP motors = 5( 15x746 ) = 55950
3 - 5 HP motors = 3( 5x746 ) = 11190
8 KW - lighting loads
3.5 KW - miscellaneous loads
DF = PFxTCL = (0.65)(55950 + 11190 + 8000 + 3500)/1000
DF = 51.12
20. By using two wattmeter method, power can be measured in
A. 3-phase, 2-wire
B. 3-phase, 3-wire C. 3-phase, 4-wire D. All of these
21. The double energy transient occur in the
A. purely inductive circuit
B. R-L Circuit
C. R-C Circuit
D. R-L-C Circuit
22. Its primary source is to provide ground source
A. zig-zag transformer
C. surge arrester
B. sectionalizer
D. tertiary transformer
23. A 20 KV/7.87 KV autotransformer has a secondary line current of 100 A.
What is the current in the common winding?
A. 139.25 A
B. 100 A
C. 60.65 A
D. 39.35 A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Solution:
Given:
Find: Icb
𝒃
24. In a star connected system, the current flowing through the line is
A. Greater than the phase current
C. Lesser than the phase current
B. Equal to the phase current
D. None of these
25. The capacitive reactance of a transmission line is 90,000 ohms per kilometer.
Find the total capacitive reactance if the transmission line is 50-km long.
A. 4.5 x 106
B. 1800
C. 90,000
D. 180,000
Solution:
𝑿
26. Three phase induction motor is more suitable than single phase because
A It’s self-starting
C. it has better power factor
B.it has better efficiency
D. all of these
27. A 100 watts 230 volts gas fitted lamp has a mean spherical candlepower of
92 Find it’s efficiency in lumens per watt
A. 11.56
B. 1.156
C. 115.6
D. 1,156
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Solution:
(
)
𝑬
28. What is the speed of an induction motor of six poles if the percent slip is
2.5%?
A. 1462 rpm
B.1170 rpm
C.877 rpm
D.1755 rpm
Solution:
Given:
Find: Nr
(
(
)
)
(
)
29. Two (2), 1 ⌀, 25-KVA transformers are connected in open-delta bank.
Determine the maximum KW the bank can supply without overloading at 0.8 p.f
lagging.
A. 43.3
B. 34.64
C. 40
D. 50
Solution:
Given:
⌀
(
(
)(
)(
⌀)
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
(
)
(
)
30. The luminous intensity is defined as
A. lumen per square meter
B.luminous flux per unit solid angle
C.illumination per square meter
D. candela per unit solid angle
31. MHO relay is used for
A. rectifier
B. circuit breaker
C. transmission lines
D. feeders
32. Three units of transformers /γ are connected to supply a 3-phase load from
a 400 volts, 3-phase source. What is the voltage on the load side?
A. 2,000v
B. 3,464v
C. 693v
D. 1,200v
Solution:
VL= √3 (400)
=693V
33. In a serious motor, what is the relation of the connection of motor field
winding with the respect of the motor armature?
A. series
B. parallel
C. series-parallel
D. delta
34. The field circuit of a 4-poledc generator has a resistance of 200Ω and an
inductance of 100H. If it is connected to a 400v supply, find the time taken for the
current to reach ljkjhggfdfd1.5A.
A. 0.125 sec
B. 1.5 sec
C. 0.369 sec
Solution:
I= 1.5A, R= 200Ω, L= 100H, E= 400v, t=?
I= E/R(1-e^(R/L) t
1.5=400/200(1-e^-(200/100) t
D. 0.693 sec
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
t= 0.693sec
35. Calculate the effective voltage in one phase of an alternator, given the
following particulars; f= 60 cps; turns per phase N = 240; flux per pole =
2.08x10^6.
A. 1,330v
B. 2,304v
C. 1,225v
D. 2,122v
Solution:
f= 60 cps, N= 240rpm, = 2.08x10^6
E= (240) (2.08x10^6)
=1324V ≠ 1330V
2 (60)
36. a 60 F capacitor is connected in series with 40,000 Ω resistor If the
capacitor is initially uncharged. Determine the resistor voltage when t= 1.5 times
the time constant for a suddenly applied source emf of 120volts.
A. 93.22v
B. 120v
C. 80v
D. 26.78v
Solution:
I= E/R(1-e^(R/L) t
I= 120
= 3 x 10^-3
40,000
3x10^-3= E/40,000 (1-e^-(40,000/60) (1.5)
E= 120v
37. What is the force on a +5x10^-11 C charge that is 5 cm form each of two
+2x10^-9 C charge that are separated by 8cm?
A. 0.432x10^-6N
B. zero
C. 0.36x10^-6N
Solution:
Q1= 5x10^-11, Q2= 2x10^-9, d= 0.05
5cm x 1m
100cm
F= KQ1Q2
= 0.05m
D. 0.14x10^-6
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
d^2
F= (9x10^9)(5x10^-11)(2x10^-9) = 0.36x10^-6
(0.05) ^2
38. A balanced delta connected load consist of 20 cis 25 Ω impedances The
60Hz line voltage 208v. What is the line current?
A. 6A
B.10.4A
C. 12A
D. 18A
Solution:
R= 20∟25 Ω, V= 208V
IL= 208v
= 10.4A
20Ω
39 The impedance of 69 kV transformer is 14 28Ω when referred to primary. The
transformer is a 10-MVA unit. What is the percent impedance of transformer?
A. 4
B. 6.2
C. 3
D. 4.5
Solution:
Zpu= (Zbase x Sbase)
Vbase^2
Zpu= (10 x 14.28)
x 100 = 2.99≠3
69^2
40. What is the cost of operating a 70percent 20hp pump for 20 days, 8 hrs per
day? Cost of energy is P0.05/kW-hr.
A. P112
B.P170.45
C. P228.60
Solution:
Pin= 20Hp, ɳ= .70, Cost of energy= P0.5kW/hr
Pin= Pout
ɳ
= 20x746
=21.31x10^3kW-hr
0.70
=20days x 8hrs = 160hrs
D. P83.55
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1day
= 160 x 0.5 = 80kW-hr
= 80 kW-hr (21.31 x 10^3)
= 170.45
41. The ratio of the wattmeter readings in three-phase inductive system is 2:1
when power is measured by the two-wattmeter method. What is the power factor
of the load?
A. 0.5
B. 0.866
C.0.75
D. 0.9
Solution:
Given: ratio: 2:1
Find: Pf=?
√ (
)
(
√ (
)
)
42. A coil of 100 turns is cut by a magnetic field that increases at the rate of 40
Wb/min. What is the induced voltage?
A. 66.7 v
B.16.7 v
C. 4,000 v
D. 6.67 v
Solution:
Given: N = 100 turns
⁄
Find: e =?
(
)
43. Find the horsepower rating of a motor running at 1,500 rpm and developing a
torque of 105 lb-ft.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 22
B. 28
C. 30
D. 36
Solution:
Given: N = 1,500 rpm
T = 105 lb-ft
Find: Hp=?
(
)(
)
44. The rms value of a sinusoidal wave is equal to _________ of maximum
value.
A. 0.637
B. 0.707
B. 0.506
D. 1.414
45. The voltage across a 50-µF capacitor rises at a constant rate of 10 V/ms.
Calculate the current through the capacitor.
A. 2 mA
B. 5 mA
C. 50 mA
D. 500 mA
Solution:
Given: C =
Find: I=?
𝐶
( ) (𝐶)
(
)(
)
46. One advantage of disturbing the winding in alternator is to
A. reduce harmonics
C. reduce the amount of copper
B. improve voltage waveform
D. decrease the value of the voltage
47. A series RLC circuit has R = 100 ohms, L = 100µH and C = 100 pF. What is
the frequency in MHZ at unity power factor?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 1.59
B. 1.36
C. 15.9
D. 13.6
Solution:
Given:
𝐶
Find: F=?
(√
)
(√(
)(
))
48. In dc machines, lap winding is used for
A. high voltage low current
C. high voltage high current
B. low voltage low current
D. low voltage high current
49. The ratio of active power to apparent power is known as _______________
factor.
A. demand
B. load
C. power
D. form
50. At ________________ frequencies, the parallel R-L circuit behaves as purely
resistive.
A. very low
B. low
C. high
51. One kilowatt equals to _ horsepower.
A. 1.26
B. 1.36
C. 1.46
D. very high
D. 1.56
Solution:
52. The output of motor in watts when in takes a power of 3 kW and its efficiency
is 75%, is
A. 2000
B. 2250
C. 2500
D. 2750
Solution:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Given:
Find:
𝒘
53. In a certain Y-Y system, the source phase currents each have a magnitude of
9 A. The magnitude of each load current for a balanced load condition is
A. 12 A
B.3 A
C. 9 A
D. 27 A
Solution:
Given:
54. In a three-phase system, the voltages are separated by
A. 90°
B. 45°
C. 120°
D. 180°
Solution:
55. In a three-phase system, when the loads are perfectly balanced, the neutral
current is
A. one-third of maximum
C. two-thirds of maximum
B. zero
D. at maximum
56. When the motor runs on no load, then
A. Back emf is almost equal to applied voltage
B. Back emf will be greater than applied voltage
C. Back emf will be less than applied voltage
D. None of these
57. What is the source of heat generation in cables?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. Copper loss in conductor
B. Dielectric losses in cable insulation
C. Losses in metallic sheathings and armouring
D. All of these
58. In a 3 core cable, the capacitance between two conductors is 3 µF. What will
be the capacitance per phase?
A. 1.5 µF
B. 3 µF
C. 6 µF
D. 12 µF
Solution:
Given: 𝐶
𝐶
𝐶
59. The process by which a heavy nucleus is splitted into two light nuclei is
known as
A. Splitting
B. Fission
C. Fusion
D. Disintegration
60. Efficiency of a power plant is more in summers or winters?
A. summers
B. winters
C. same in both
D. depends on variation
61. If there are eleven resistors of 33 kΩ each in parallel, what is the total
resistance?
A. 363 kΩ
B. 3.3 kΩ
C.
Ω
D. 16 5 kΩ
Solution:
Given:
Find:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
62. To reverse the direction of rotation of a three-phase induction motor, it is
necessary to
A. interchange all the three line connections
B. reverse the polarity of the rotor circuit
C. increase the resistance of the rotor circuit
D. interchange any two of the three line connections
63. The law that induced emf and current always opposes the cause producing
them was discovered by
A. Lenz
B. Maxwell
C. Faraday
D. Ohm
64. The power factor of an alternator is determined by its
A. speed
B. load
C. excitation
D. prime mover
65. A heater wire of length 50 cm and 1 mm 2 in cross-section carries a current of
2 A when connected across a 2 v battery. What is the resistivity of the wire?
A. 2 x 10-6 Ω-m
B. 2 x 10-8 Ω-m
C. 4 x 10-6 Ω-m
D. 4 x 10-8 Ω-m
Solution:
Given:
(
)
Find: ρ
(
)(
)
66. A six-pole three-phase 440-v, 60 Hz induction motor develops 10-hp at 1,150
rpm, the power factor being 80% lagging. Stator and core losses amount to
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
400 w and 350 w, respectively. Frictional losses amount to 0.5-hp. Calculate the
motor line current.
A. 12.24 A
B. 13.41 A
C. 11.42 A
D. 14.64 A
Solution:
Given:
Find:
(
(
√
(
)(
√ (
)
)
)
)(
)
67. In a circuit containing R, L, and C, power loss can take place in
A. C only
B. L only
C. R only
D. all of these
68. The efficiency of thermal power plant is approximately
A. 10%
B. 30%
C. 60%
D. 80%
69. The time constant of a series RC circuit is given by
A. R/C
B. RC2
C. RC
D. R2C
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
70. A power plant consumes 3,600 tons of coal per day. If the coal has an
average energy content of 10,000 BTU/lb, what is the plant’s power output?
Assume an overall efficiency of 15 percent.
A. 132 MW
B. 130 MW
C. 128 MW
D. 126 MW
Solution:
Given:
Find:
(
)
71. A resistance of 40 ohms and inductance of 79.6 mH are connected in parallel
across a 240 v, 60 Hz ac supply. Find the total current in amperes.
A. 11
B. 12
C. 10
D. 14
Solution:
Given:
Find:
(
)(
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
√
√
72. A 230 v, 3-phase source supplies a balanced delta connected load with
impedance of 8-j6 ohms per phase. Calculate the line current in amperes.
A. 33.1
B. 39.8
C. 26.5
D. 29.3
Solution:
Given:
Find:
√ (
√
)
73. Three unbalanced 3-phase currents are given as follows:
Ia=10 -30° A, Ib=0, Ic=10 -150° A
A. 3.34 150° A
B. 3.34 -150° A
C. 3.34 30° A
D. 3.34 -30° A
Solution:
Given:
|
Find:
|
|
| | |
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
(
)
)
[(
(
)( )
(
)(
)]
74. A three-phase, 6 pole, 50 Hz, induction motor develops a maximum torque of
30 N-m at 960 rpm. Calculate the torque produced by the motor at 6% slip. The
rotor resistance per phase is 0 6 Ω
A. 24.7 N-m
B. 25.7 N-m
C. 26.7 N-m
D. 27.7 N-m
Solution:
Given:
Find:
(
( )
(
(
( )
( )
)(
( )
)
)
)
(
)
(
)
(
)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
75. A device that repeatedly reverses the polarity of a magnetic field in order to
keep a dc motor rotating is known as
A. a solenoid
B. an armature coil C. a commutator D. a field coil
76. The form factor is the ratio of
A. peak value to r.m.s value
B. r.m.s value to average value
C. average value to r.m.s value
D. none of these
77. The per unit impedance of a circuit element is 0.30. if the base KV and base
MVA are halved, then the new value of the per unit impedance of the circuit
element will be.
A. 0.30
B. 0.60
C. 0.0030
D. 0.0060
Solution:
Given:
⁄
⁄
Find:
(
)(
(
𝒁
⁄
+(
)
⁄
+
𝒘
78. If two sinusoids of the same frequency but of different amplitudes and phase
angles are subtracted, the resultant is
A. a sinusoidal of the same frequency
C. a sinusoidal of double the freq
B. a sinusoidal of half the original frequency D. not a sinusoid
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
79. A 170-mile, 230 V, 60 Hz, three-phase single circuit transmission line uses a
triangular arrangement with 20 ft, 20 ft, and 36 ft spacing respectively. If the line
conductors have a radius of 0.0217 ft, determine the capacitive susceptance to
neutral per mile.
A. 4.81 x 10-8 mho per mile
C. 7.92 x 10-6 mho per mile
B. 12.74 x 10-8 mho per mile
D. 2.47 x 10-6 mho per mile
Solution:
Given:
√(
√
)(
)(
(
𝐶
)
)
𝐶
𝐶
(
)
80. An 8-pole lap wound dc generator has 1,000 armature conductors, flux of 20
mWb per pole and emf generated is 400 v. What is the speed of the machine?
A. 1,000 rpm
B. 1,800 rpm
C. 1,200 rpm
D. 1,500 rpm
Solution:
Given:
Find:
( )( )
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
(
( )(
)( )( )
)(
)
81. In a balanced 3-phase system, wye-connected voltage source with phase
sequence abc, Vab = 230 10o V. Find the phase voltage Vcn.
A. 230 -230oV
B. 132.8 -80o V
C.132.8 -140o V D. 132.8 -260o V
Solution:
Given:
Find:
√
√
82. A three-phase 60 Hz wye-connected wound rotor synchronous generator
rated at 10 kVA, 230V has a synchronous reactance of 1.2 ohm per phase and
an armature resistance of 0.5 ohm per phase. Calculate the percent regulation at
full-load with 0.8 lagging power factor.
A. 18.3%
B. 20.8%
C. 21.8%
D. 22.5%
Solution:
Given:
Find:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
√(
)
(
)
83. Two equally charged spheres repel each other with a force of 0.1kg. If their
centers are 20 cm apart, find the charge on each.
A. 2.09 x 10-6 coul B. 2.09 x 106 coul C. 2.00 x 10-6 coul D. 2.00 x 106 coul
Solution:
Given:
Find:
√
√
(
√
)(
)(
)
84. The area of one plate of a two-plate mica capacitor is 0.0025 m2 and the
separation between plates is 0.02 m. If the dielectric constant of mica is 5, what
is the capacitance of the capacitor?
A. 5.53 µF
B. 5.53 pF
C. 7.74 µF
D. 7.74 pF
Solution:
Given:
Find: 𝐶
𝐶
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
𝐶
)( )(
(
)
𝐶
85. For coil having a span of 2/3 of pole pitch, the coil span factor is
A. 0.8
B. 0.866
C. 0.786
D. 0.966
Solution:
Given:
Find:
(
(
)
*
86. The number of parallel paths in a simplex lap winding is equal to
A. 2
B. number of poles
C. number pair of poles
D. 1
Solution:
Given:
Find:
(
)
87. A 240 V DC series motor develops a shaft torque of 200 N-m at 92%
efficiency while running at 600rpm. Calculate the motor current.
A. 62.09 A
B. 52.36 A
C. 48.17 A
D. 56.91 A
Solution:
Given:
Find:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
(
)(
)
88. A voltage of e = 70.7sin50t V is applied to a series circuit containing a
resistance of 4 ohms and an inductance of 60 mH. What is the impedance of the
circuit in ohms?
A. 5 30˚Ω
B. 5 60˚Ω
C. 5 53 13˚Ω
D. 5
7˚Ω
Solution:
Given:
Find:
(
)
89. An office, 17m by 8m, is lighted by 10 lamps and each lamp has a luminous
intensity of 200 cd. Allowing an absorption loss of 5,000 lm for the reflectors,
walls, and ceilings, calculate the average illumination on the working plane.
A. 177 lm/m2
B. 136 lm/m2
C. 118 lm/m2
D. 148 lm/m2
90. A 480-V rms line feeds two balanced three-phase loads.
If the two loads are rated as follows,
Load 1: 5 kVA at 0.8 p.f. lagging
Load 2: 10 kVA at 0.9 p.f. lagging
Determine the magnitude of the line current from the 480-V rms source.
A. 17.97 A
B. 14.94 A
C. 13 A
D. 7.36 A
Solution:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Given:
Find:
√
√ (
)
91. A colliery workshop 20 m x 10 m requires an average illumination of 135
lm/m2 on the working plane. Calculate the electrical power and current required
for the purpose. Allow a coefficient of utilization of 0.45 and a depreciation factor
of 1.4. The supply is 230-V at 50 Hz and the efficiency of each of the lamps is 12
lm/W.
A. 8kW, 34.8 A
B. 9kW, 39.1 A
C. 6kW, 26.1 A
D. 7kW, 30.4 A
Solution:
92 A series RL circuit has R = 6 Ω and XL = 8 Ω What is the circuit admittance?
A. 0.06 mho
B. 0.1 mho
C. 0.08 mho
D. 0.125 mho
Solution:
Y = Z-1
Y = (6 + j8)-1
Y = 0.06 – j0.08 0.1 - 59.03
Y = 0.1 mho
93. A balanced 6,600-volt, 3-phase, 3-wire, 60 Hz transmission line is designed
to transmit power to a 450 kVA inductive load at 0.8 power factor. The line has a
resistance of 3.5 ohms and a reactance of 10.5 ohms per wire. Find the voltage
regulation of the line.
A. 7.6%
B. 5.6%
C. 9.6%
D. 11.6%
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Solution:
94. A balanced Y-connected load of 300 j100 Ω s supplied by a 3-phase line
40 km long line with an impedance of 0 6 j0 7 Ω per km line to neutral Find
the voltage at the receiving end when the voltage at the sending end is 66 kV.
A. 60 kV
B. 62 kV
C. 58 kV
D. 64 kV
Solution:
ZT = 300
Is =
(
j100
)
=
40 0 6
j0 7 = 324
j128 Ω
= 189.46 -21 56˚ = IR
VR = IR ZT = (189.46 -21 56˚ (300 + j100)
VR = 59.9 kV -3 12˚
VR 60 kV
95. A plant has a total generating capacity of 800 kW. The coal consumption is
1,900 lbs. per hour. Heating value of the coal is 9,500 BTU per lb. What
approximate percent in heat in the coal is converted into useful energy?
A. 8.7 %
B. 17.5 %
C. 12.3 %
D. 15%
Solution:
9,500
x 1900
= 18.05 x 106
x
= 5288.6 kW (100%)
=
x = 15.13%
15%
96. A 100 km transmission line has a 1,200 ohms shunt reactance. What is the
shunt reactance per km?
A 1,200 Ω
B 120,000 Ω
2Ω
D 120 Ω
Solution:
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
MARCH 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
= 12
97. A relay is used to
A. receive a signal and record it
B. protect a circuit
C. connect a line to the source
D. relay a message to a remote place
98. A power plant consumes 100,000 lbs. of coal per hour. The heating value of
the coal is 12,000 BTU per lb. the overall plant efficiency is 30%. What is the kW
output of the plant?
A. 175,000 kW
B. 142,500 kW
C. 105,500 kW
D. 205,000 Kw
Solution:
100
x 12,000
= 1.2
x
= 351. 597 kW
=
Po = 105, 500 kW
99 The condition in Ohm’s law is that
A. ratio V/I should be constant
B. current should be proportional to voltage
C. the temperature should remain constant
D. the temperature should vary
100. How is the storage battery rated in capacity?
A. volts
B. watts
C. amperes
D.
ampere-hour
AUGUST 2018
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1. In the transformers
A. high tension winding is used near the core
B. high tension winding is used away from the core
C. low tension winding is used near the core
D. low tension winding is used away from the core
2. Which of the following parameters can be neglected for a short line?
A. resistance
B. inductance
C. reactance
D. capacitance
3. Find the frequency of a radio wave whose wavelength is 600m.
A. 500Hz
B. 500kHz
C. 150Hz
D. 150kHz
Given:
Req’d: f
L= 600m
Solution:
L= v ;
f
f = v = 3 x 105 m/s = 500kHz
L
600m
4. The curve representing Ohm’s law is
A. a parabola
B. linear
C. a sine function
D. a hyperbola
5. A series connected circuit has R= 4Ω and L=25mH Calculate the value of C that will
produce a quality factor of 50.
A. 62.5µF
B. 6.25µF
C. 0.625µF
D. 25µF
Given:
R= 4Ω
Req’d: C
L=25mH
Qfactor = 50
Solution:
Q.F. = 1/ R (√L/C)
50 = ¼ (√25 x 10-3 / C)
C= 0.625µF
6. The overcurrent protective device is caused to operate by ___________________.
A. voltage surge
B. current flow
C. voltage drop
D. impedance
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
7. What is the maximum number of bands permitted in rigid conduits between outlets?
A. 4 quarter bends
C. 2 quarter bends
B. 6 quarter bends
D. 3 quarter bends
8. Which of the following insulators will be selected for high voltage application?
A. strain type
B. disc type
C. suspension type
D. pin type
9. At a 115kV substation, the PT ratio is 1000 and the CT ratio is 1200/5. The potential
going into the wattmeter is 115volts. What is the MW indicated when the wattmeter
reads 800 watts?
A. 150 MW
B. 192 MW
C. 15 MW
D. 19.2 MW
Given:
V=115kV
PTR=1,000
CTR=1200/5
VW= 115V
Prdg= 800W
Req’d: Pactual in MW
Solution:
Pactual = Prdg (PTR x CTR)
= (800) (1000 x 1200/5)
= 192 x 106
= 192 MW
10. An inductive coil consumes active power of 500W and draws 10A from a 60Hz ac
supply of 110V. What is the coil inductance?
A. 26mH
B. 28mH
C. 30mH
D. 32mH
Given:
V= 110Vf = 60Hz
I = 10A
P= 500W
Req’d: L
Solution:
R= P/ I2 = 500 / (10)2 = 5Ω
Z= V / I = 110 / 10 = 11Ω
Z= √R2 + XL2
XL= √Z2 – R2
XL= √112 - 52
XL= 9 78Ω
L= XL / 2лf
= 9 78 / 2л 60
= 25.94 x 10-3
L=26mH
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
11. If the torque angle continuously increases, system will become
A. stable
C. oscillatory stable
B. unstable
D. asymptotic stable
12. The condition in Ohm’s Law is that
A. ratio V/I should be constant
B. current should be proportional to voltage
C. the temperature should remain constant
D. the temperature should vary
13. Which of the following shall be included in the calculation of the reliability standard
indices of the distributor asset by the Philippine Distributor Code?
A. Outages that occur on the secondary lines of the distribution system
B. Planned outages where the customers have been notified at least three(3)
days prior to the loss of power
C. Outages that occur on the primary lines of the distribution system
D. Outages that occur in the transmission line
14. If 25 ohms and 125 amperes are the base impedance and base current, respectively
for a given system, what is the base KVA?
A. 781.25
B. 39.1
C. 390.625
D. 76.12
Given:
Zbase= 25Ω
Req’d: kVAbase
Ibase = 125A
Solution:
kVAbase= Ibase2 x Zbase
= (125)2 (25)
kVAbase= 390.625
15. A type of electronics communication in which only one party transmits at a time.
B. Full duplex
B. Half duplex
C. Bicom
D. Simplex
16. An equal number of electrons is placed on two metal spheres 3cm apart in air. How
many electrons are on each sphere if the resultant force is 4kN?
A. 1.47 x 1014 electrons
C. 1.25 x 1014 electrons
B. 1.33 x 1014 electrons
D. 1.40 x 1014 electrons
Given:
d= 3cm
Req’d: e
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
F= 4kN
Solution:
F= kQ1Q2 / d2
4x103 = (9x109)(Q)2 / (3x10-2)2
Q= 2x10-5
Qe = 1.6x10-19
e = 2x10-5 / 1.6x10-19
e = 1.25 x 1014 electrons
17. Base load plants are designed to supply power at
A. low capital cost and low operating cost
B. high capital cost and low operating cost
C. low capital cost and high operating cost
D. high capital cost and high operating cost
18. Peak load plants are designed to supply power at
A. low capital cost and low operating cost
B. high capital cost and low operating cost
C. low capital cost and high operating cost
D. high capital cost and high operating cost
19. A symmetrical three-phase 240V supplies a balanced delta connected load of 6-j8
ohms per phase. What is the line current?
A. -25 + j32A
B. 25 – j5.78A
C. -25 - j32A
D. 25 + j32A
Given:
V= 240V
Z= (6-j8 Ω
Req’d: IL
Solution:
Iɸ = V / Z = 240 / 6-j8 = (14.4+j19.2) A
IL = Iɸ x √3 = (14.4+j19.2) (√3)
= 24.9+j33.3 A
IL = 25 + j32A
20. A 440V, 60Hz, 6 pole, 3 phase induction motor has a rotor input power of 33kW at
rated voltage and frequency. Under this condition, the rotor emf makes 126
complete cycles/minute. Find the rotor resistance in ohms/phase if the rotor current
is 60A/phase.
A. 0.0118
B.0.0107
C. 0.107
D. 0.118
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
21. If the effect of earth is taken into account, then the capacitance of line to ground
A. decreases
C. remains unchanged
B. increases
D. becomes infinite
22. The effective resistance of conductor is increased by
A. skin effect
C. corona effect
B. proximity effect
D. both (a) and (b)
23. Surge impedance of transmission line is given by
A. √C/L
B √LC
C 1/√LC
D √L/
24. A 100 watts 230 volts gas fitted lamp has a mean spherical candle power of 92. Find
its efficiency in lumens per watt.
A. 9.56
B. 10.56
C. 11.56
D. 12.56
Given:
P= 100W
I = 92mscp
V=230V
Solution:
n = Im / P = 4лI / P = 4л 92 / 100 = 11.56
25. The overload KVA of each transformer of an open-delta bank is 11.56. If each
transformer is rated 37.5 KVA, then what is the KVA of the balanced 3ɸ load?
A. 70
B. 80
C. 85
D. 90
Req’d: Sload
Given:
S1ɸ = (37.5 + 11.55) KVA
Solution:
S1ɸ = Svv / √3 = Sload / √3
S1ɸ = Sload / √3
Sload = S1ɸ √3 = (37.5 + 11.55) √3 = 84 96
85
26. In a 6-pole alternator how many mechanical degrees is the equivalent of 180
electrical degrees?
A. 60
B. 30
C. 120
D. 90
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Req’d: Θm
Given:
P= 6
Θe= 180
Solution:
Θe= P / 2 Θm
Θm= Θe / (P / 2) = 180 / (6 / 2) = 60
27. A two terminal pair of network of a transmission line can be represented by a
A. Л- network
B. T-network
C. either (A) or (B) D. tree network
28. In television system, channels 2 and 13 are classified as
A. VHF
B. UHF
C. SHF
D. EHF
29. An aluminum cable has 10 identical strands, a length of 1,500m and a diameter of
2.50 mm each. What is the resistance of the cable?
A. 86 3Ω
B
Ω
C 56 3Ω
D 0 563Ω
Req’d: R
Given:
n = 10 identical strands
L = 1, 500m
d = 2.50mm = 2.5 x 10-3 m
ρ = 2 83 x 10-8 Ωm @ 20 0C
Solution:
R=ρ L/A
= ρ { L / л / 4 d2 n) }
= 2.83 x 10-8 { 1, 500 / л / 4
R=
2 5 x 10-3 )2 x 10 ) }
Ω
30. An ACSR conductor has (n-1) layers around its single center strand, the total
number of strands will be
A. 3n2 + 3n +1
B. 3n2 - 3n -1
C. 3n2 + 3n -1
D. 3n2 - 3n +1
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
31. Three resistors A, B and C are connected in series to a 120V supply. If the the
resistor A=50 ohms and the voltage across resistor B=40V when the current is 1/2A,
what is the resistance of resistor C in ohms?
A. 105
B. 90
C.110
D.100
Req’d: Rc
Given:
RA = 50Ω
VT = 120V
VB = 40V
I = 1/2A
Solution:
RB = VB / I = 40 / 1/2 = 80Ω
RT = VT / I = 120 / 1/2 = 240Ω
RT = RA + RB + Rc
240 = 50 + 80 + Rc
Rc = 240 - 50 – 80 =
Ω
32. An inductor motor with 8 poles, 60Hz is operated with a slip of 3%. Calculate the
rotor speed.
A. 1,684
B.1,024
C. 873
D. 927
Req’d: Nr
Given:
P=8 poles
f= 60Hz
%s= 3%
Solution:
Ns= 120f / p = 120(60) / 8 = 900rpm
%s = (Ns-Nr) / Ns
0.03 = (900- Nr) / 900
Nr = 900 – 0.03(900) = 873rpm
33. Which of the following methods of generating electric power from the sea water is
more advantageous?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. water power
B. ocean power
C. tidal power
D. none of these
34. When installing two grounding electrodes, the minimum distance between them is
A. 1,800 mm
B. 2,000 mm
C. 1,500 mm
D. 2,400 mm
35 A 36 resistor is connected in parallel with an unknown resistor R Their
combination is them connected in series with a 12 resistor Find the value of R such
that the power drawn by the parallel combination of 36 and R is equal to the power in
the 12 resistor
A 6
B
C 24
D 48
Solution:
P1 = Peq
V1=V2
V1 = V1
R1 Req
R1 = Req
R1 = R (36)/R + 36
R = 18 Ω
36. The current flowing in L and C at parallel resonance are
A. zero
B. equal
C. infinite
D. Difference
37. What does PEMC in EPIRA stands for
A. Philippine Energy Market Corporation
B. Private Energy Marketing Company
C. Philippine Energy Market Corporation
D. Philippine Electrical Marketing Corporation
38. For two alternators operating in parallel, if the load shared by one of the, to be
increased, as field excitation is
A. to be strengthened keeping input torque the same
B to be weakened keeping input torque the same
C. to be kept constant but input torque should be increased
D. to be kept constant but input torque should be decreased
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
39. A 7.5 MVA, 69/13.8 kV, 3-phase transformer has 8% impedance. What us the per
unit impedance at 10 MVA base?
A. 0.24
B. 0.106
C. 0.06
D. 0.096
Given:
Zpuold = 0.08 pu
Sold = 7.5 MVA
Snew =10 MVA
Solution:
Zpunew = Zpuold (Zpuold / Sold)
= 0.08 ( 10 / 7.5 )
= 0.106 pu
40. Open circuit test on transformer is conducted to determine
A. hysteresis loss B. copper loss
C. core loss
D. eddy current loss
41. Which of the following power plant is a conventional source of energy?
A. Solar energy
B. Geothermal energy C. Coal energy D. Wind energy
42. A transformer is rated 10kVA, 440/110V and 60 Hz when operated as conventional
2 winding transformer. This transformer is to be used as 550/440 V step-down
autotransformer in a distribution system. What is the new kVA rating of the transformer
in this manner?
A. 20
B. 10
C. 37.5
D. 50
43. In a synchronous motor, the magnitude of stator back emf depends on
A. load on the motor
C. both the speed and rotor flux
B. dc excitation only
D. none of theses
44 A dc ammeter has an internal resistance of 0 1
A shunt of 1 01 x 10 -3
connected to be ammeter. What is the multiplier of the set up?
A. 10
B. 50
C. 80
D. 100
Given:
Rg = 0.1 Ω
Rsh = 1.01x10-3 Ω
is
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Solution:
Multiplier = (Rg + Rsh) / Rsh
= (0.1 + 1.01x10-3) / 1.01x10-3
= 100
45. A single-phase, 10-km transmission line has 16.65 mH total inductance. If the
distance between the conductors is 1 m, what is the conductor radius?
A. 2 cm
B. 1.5 cm
C. 1 cm
D. 0.75
Given :
Lt = 16.65 mH
D=1
Solution:
Lt = 4x10-7 ln (d/ 0.7788r)
Lt = 16.65 mH x (1 / 10,000 m)
Lt = 1.665x10-6 H/m
1.665x10-6 = 4x10-7 ln (d/ 0.7788r)
r = 0.0199 m or 2 cm
46 4-pole wave wound generator has 220 coils of 10 turns each. The resistance of each
turn is 0 02
Find the resistance of armature winding.
B 22
C 02
D 0 44
Solution:
Ra = (220 coils)(10 turns x 0.02 Ω) / 4 Poles
Ra = 11 Ω
47. PDC in EPIRA means
A. Philippine Distribution Commission
B. Philippine Distribution Code
C. Philippine Distribution Corporation
D. Philippine Distribution Company
48. What is the maximum plug and cord rating of a 30 A branch circuit?
A. 24 A
B. 30 A
C. 26 A
D. 28 A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Solution:
Rating = 80 % of OCPD
= 0.8 ( 30 A )
Rating = 24 A
49. Wavelength is the distance travelled by an electronic wave during the time of one
cycle. Given a wavelength of 12 meters, what is the frequency?
A. 250 kHz
B. 25 kHz
C. 250 MHz
D. 25 MHz
λ = 12 m
Given:
Electronic wave = 3x108 m/sec.
Solution:
λ = V/f
f = (3x108) / 12
f = 25 MHz
50. Alternators installed in a hydro power station, are of
A. low speed
B. high speed
C. medium speed D. very high speed
51. A sine wave has a frequency of 60 Hz. Its angular frequency is
A. 120 π
B 60 π
C 30 π
D 6π
Solution:
f= 60 Hz
ω= 2π (60)
ω
2 π
52. In a loss-free RLC circuit, the transient current is
A. oscillating
B. Square wave
C. sinusoidal
D. non-oscillating
53. What is the maximum flux in mWb of a transformer with 200 primary turns when
connected to a 60 Hz, 200 V supply?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 10.35
Given:
B. 6.25
C. 50.5
D. 3.75
N= 200 turns
f= 60 Hz
E= 200V
⌀= ?
Solution:
E= 4.44 Nf⌀
⌀ = E / 4.44Nf
⌀= 200 / (4.44x200x60)
⌀= 3.75 mWb
54. A 60 Hz, 4 pole, 3 phase induction motor has a slip of 2.5 %. What is the slip speed
in rpm ?
A. 55
B. 40
C. 60
D. 45
Given:
f = 60 Hz
P=4
S= 2.5%
NSLIP =?
Solution:
Ns = 120f/ P
Ns = 120(60) / 4
Ns = 1800 rpm
Nr = Ns (1-s)
= 1800 (1 – 0.025)
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Nr = 1755 rpm
NSLIP = Ns-Nr
NSLIP= 1800-1755
NSLIP = 45 rpm
55. A 15 hp, 460 V, 60 Hz, 6-pole, 3 phase induction motor has full-load slip of 4%. Find
the full-load torque in N-m.
A. 85
B. 88
C. 93
D. 90
Given:
POUT = 15 HP
f = 60 Hz
P = 6 Poles
S=4%
T=?
Solution:
HP = 2πNrT / 44,760
Nr = (120f/P) / (1-s)
= ((120x60)/6) / (1-0.04)
Nr = 1152 rpm
T = HP (44,760)/ 2πNr
= (15) ( 44,760)/ 2π(1152)
T= 92.76 N-m or 93 N-m
56. At very low frequencies a series RC circuit behaves as almost purely
A. resistive
B. inductive
C. capacitive
D. none of these
57. A power plant gets water from a dam from a height of 122.45 m at the rate of 1,000
cubic meters per minutes. If the output of the plant is 15,000 kW, what is the plant
efficiency?
A. 80%
B. 75%
C. 70%
D. 65%
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Given:
h = 122.45 m
Q = 1000m3 / min. x (1 min/ 60 sec.) = 16.67 m3 / sec.
Pout = 15,000 kW or 15 MW
Solution:
Pin = Qwh
Specific weight of water W = 9810 N/m3
Pin = (16.67)(9810)(122.45)
= 20 MW
n = (Pout / Pin) x 100
= (15 MW / 20 MW) x 100
n = 75 %
58. A 500 kVA, 34.5/13.8 kV, 3-phase transformer is delta-wye connected. The primary
and secondary winding resistances are 35 ohms and 0.876 ohm per phase,
respectively. Calculate the percent efficiency at full-load and unity power factor id core
loss is 3 kW.
A. 97.8
B. 98.7
C. 96.4
D. 97.2
Given:
S = 500 kVA
rp = 35 ohms
34.5/13.8 kVA
rs = 0.876 ohms
Pcore = 3 kW
n=?
Solution:
Refer to secondary side
Rs = rs + rpa2
= 0.876 + 35 ((13.8/ √3)/34.5)2
= 2.743 ohms
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Is = S / √3 Vs)
= 500x103 / √3x13.8103 )
= 20.92
@ Unity pf
Po = S = 500kW
Pcu = 3Is3Rs
= 3 (20.92)2 (2.743)
= 3601.39 W
n = (Po/Pi)x100 = (Po/Po+Pcu+Pcore)x100
= 500x103 / (500x103 + 3x103 + 3601.39)
n = 98.7 %
59. One of the advantages of distributing the winding in alternators is to
A. reduce harmonics
C. improve voltage waveform
B. reduce the amount of copper
D. decrease the value of the voltage
60. The effect of corona is
A. increased reactance
B. increased inductance
C. Increased energy loss
D. all of these
61. The rms value of pure cosine function is
A. 0.5 of peak value
B. 0.707 of peak value
C. same as peak value
D. zero
62. Calculate the use factor of a power plant if the capacity factor is 35% as it operates
8,000 hours during the year.
A. 38.32%
B. 33.82%
C. 36.82%
D. 32.54%
63. How many commutator bars does a 6-pole dc generator with 4 coil elements per slot
and 20 slots per pole has?
A. 60
B. 120
C. 240
D. 480
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Solution:
Z = (4 Coil/ Slot x 20 Slot/Pole) ( 6 Pole )
= 480 Coils
Nc = Z/2
= 480 / 2
Nc = 240 Coils
64. A coil having a resistance of 10 and an inductance of 4 H is switched across a 20
V dc source. Calculate the rate of current change when the current reaches 50% of its
final steady value.
A. 2.5 A/s
B. 3.5 A/s
C. 4.5 A/s
D. 5.5 A/s
Solution:
XL = 2π(60)(4)
= 480π
ISV = V/Z
IFSV (50%) = 20 / (√102 + 480π2)
IFSV = 0.026 (100)
IFSV = 2.65 A or 2.5 A/s
65. Calculate the torque in N-m developed by a 440-V dc motor having an armature
resistance of 0 25 and running at 750 rpm when taking a current of 60 A
A. 240
B. 325
C. 285
D. 342
Given:
V = 440
Ra = 0.25
Solution:
Eg = VL – IaRa
= 440 – (60)(0.25)
N = 750 rpm
IL = 60 A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
= 425 V
Pd = (425)(60)
= 25,500 N
HP = 25,500/746 = 34.182 HP
HP = 2πNrT / 44,760
34.182 = (2πx750xT / 44760
T = 324.67 or 325 T-N
66. In a 13.8 kV, 10 MVA base three-phase system, a phase to phase fault occurs. If
the Thevenin’s equivalent impedance of the system is 2 63%, what is the per unit fault
current?
A. 19.01 pu
B. 32.93 pu
C. 57.03 pu
D. 98.78 pu
Solution:
ILL = √3/2
10 MVA/ √3 13 8 kV 0 0263
ILL = 13776.38
Ipu = I FAULT/ I BASE
= 13776.38 / ( ( 10MVA/ √3 13 8kVA
= 32. 93 pu
67. A single-phase transmission line having a length of 15 miles is composed of two
copper conductors spaced 7ft apart having a diameter of 0.0575inch. Determine the line
to line capacitance in farad if the system frequency is 60Hz.
A. 4.9 x10-12
B. 9.8 x10-12
C. 11.8 x10-9
D. 118 x10-9
68. What is the equivalent IEEE device function number for directional power relay?
A. 21
B. 32
C. 37
D. 87
69. Energy radiated continuously in the form of lighting waves is called?
A. luminous intensity
B. lumen
C.luminousflux
D. illumination
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
70. Efficiency is secondary consideration in case of
A. base load plants
C. both base load and peak plants
B. peak load plants
D. none of these
71. A capacitor is charged with 10,000 µC. If the energy stored is 1 joule. Find the
capacitance
A. 5µF
B. 50µF
C. 500µF
D. 5,000µF
Solution :
W= 1/2 (Q2/C)
1j = 1/2 ( (10,000 x10-6)2/C)
C= 50µF
72. To a series RLC circuit, a voltage of 10 v is applied. if Q of the coil at resonant
frequency is 20., the voltage across the inductor at resonant frequency will be
A. 200 v
B. 100 v
C. 75 v
D. 50 v
Solution:
Q-factor = EL / Ep
EL = ( Qfactor ) ( Ep )
= ( 20 ) (10 )
EL = 200 V
73. A 75 KVA, 13,200/240, 60Hz, single-phase transformer has 1% resistance and 3%
reactance. Find the copper loss of the transformer at 3/4 of full-load and unity power
factor.
A.155 W
B. 422 W
C. 368 W
D. 508 W
74. The starting current of a 15 hp, 460 v, 3 phase induction motor is 130 A. What
voltage in volts should be applied to the motor so that the starting current will not
exceed 84.8 A.
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 238
B. 295
C. 300
D. 310
75. The condition of a liquid electrolyte is measured in terms of its
A. current value
76. If the
B. specific gravity C.acid content
D.voltage output
of a dc shunt motor is opened
A. it will continue to run at its rated speed
B.the speed of the motor will become very high
C.The motor will stop
D.the speed of the motor will decrease
77. An ideal full-wave rectifier with non-inductive load has zero transformation losses.
What is the efficiency?
A. 70%
B. 80%
C. 90%
D. 100%
78. In an ACB sequence balanced 3 phase system, the angle between the line voltage
and the line current is 50°, what is the lagging power factor of the system?
A. 0.30
B. 0.50
C. 0.64
D. 0.94
79. A power station supplies 60 KW to the load over 2,500 ft of 000 2-conductor copper
feeder the resistance of which is 0.078 ohm per 1,000 ft. The bus-bar voltage is
maintained constant at 600 volts. Determine the maximum power which can be
transmitted.
A. 60 KW
B. 230.7 KW
C. 120 KW
D. 150 KW
80. IF a certain conductor has an area of 336.400 circular mils, what is the radius of this
conductor in cm?
A. 0.0663
B. 0.810
C. 0.737
D. 0.921
Solution:
Acm = d2
d = 2r
r = [290 x (1/100 in)] [2.54 cm/1in]
d2 = 336,400
r=d/2
r = 0.737
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
d = 580
r = 580 / 2
81. In laboratory experiment, the impedance of a coil was obtained at 60Hz and 30Hz.
These are 75,48 ohms and 57.44 ohms , respectively . What is the inductance of the
coil?
A. 150 mH
B. 182.5 mH
C. 42.5 mH
D. 2.1 mH
Solution:
Z2 = R2 + XL2
XL = 2π fL
60 Hz , ( 75.48 )2 = R2
2π 60 L
2
-------- eq. 1
30 Hz , ( 57.44 )2 = R2
2π 30 L
2
-------- eq. 2
Solve 2 equations
L = 150 mH
82. The dummy coil in dc machines is used to
A. eliminate reactance voltage
B. eliminate armature reaction
C. bring about mechanical balance of armature
D. eliminate harmonics developed in the machine
83. A half wave rectified sine wave has a averange value of 100 amperes. What is its
effective value ?
A. 157 A
B. 70.71 A
C. 100 A
D. 141.4 A
Solution:
Half wave ,
Vave = 0.318 Vmax
Vrms = 0.5 Vmax
100 = 0.318 Vmax
Vrms = (0.5)(314.465)
Vmax = 100 / 0. 318
Vrms = 157.23 A
Vmax = 314.465 v
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
84. A 3-phase transmission line has two aluminum conductors in bundle. The self GMD
of each conductor is 8.90 mm and the distance between the conductors and phase is
40cm and 9m, respectively. What is the inductance of the line per phase ?
A. 1 µH/m
B. 2 µH/m
C. 3 µH/m
D. 4 µH/m
Solution:
L = 2x10-7 ln ( Dm / Ds )
Dm = ?
d1 = 40 cm = 0.4 m
Ds = 8.9 mm
d2 = 9 m
for bundled conductor
Dm = Dmxy = squareroot d1d2
= (0.4) (9) = 1.879m x (1000mm / 1m) = 1879mm
L = 2x10-7 ln (1879 / 8.9)
L = 1.07x10-6 H / m
L = 1.07 µH/m
85. The purpose of insulating oil when used on power circuit breaker are the following.
EXPECT:
A. Interrupter
B. Coolant
C. Insulation
D. Quencher
86. A wind generator with an efficiency of 80% has a blade diameter of 20 m. If the wind
velocity is 30 Km/hr, how much power in KW is obtained from the generator?
A. 58.47
B. 45.78
C. 48.75
D. 54.87
Solution:
For wind plant
Pin = 0.2962 D2 V3
P = Watts
D = Blade diameter (m) = 20m
V = wind velocity ( m/s )
V = ( 30 Km / hr ) ( 1 hr / 3600 sec ) ( 1000 / 1 km )
V = ( 25/3)m/s
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Pin = ( 0.2962 ) ( 20 )2 ( 25/3 )
Pin = 68.56 KW
PRating = n ( Pin )
= 0.8 ( 68.56 )
PRating = 54.85 KW
87. The field system of a 50 Hz alternator has a sinusoidal flux per pole of 0.1 Wb .
Calculate the emf generated in one turn which span two-thirds of a pole pitch.
A. 17.4 v
B. 19.2 v
C. 12.2 v
D. 9.6 v
Solution:
E = 4.44 Kd Kp f Φ N
Kd = 1 ( since not stated / assumed )
Kp = sin ( 90deg x pitch )
Kp = sin ( 90 x 2/3 )
Kp = 0.866
E = (4.44)(1)(0.866)(50)
E = 19. 2 V
88. A dc shunt motor develops 15 hp at 120 v . If the effective armature resistance is
0.061 ohm and the field winding draws 2 amperes, what is the overall efficiency?
A. 90%
B. 93%
C. 94%
D. 95%
Solution:
Pd = 15hp x 746 = 11.19 KW
PspL = 0 since not given
Pd = Pout + PspL
PLoss = Pcu + PspL
= 11.19 + 0
Pd = 11.19 KW
PLoss = Ia2 Ra + Vsh Ish
PLoss = (98.15)2 (0.061) + (120)(2)
PLoss = 827.60 W
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
η= ( Pout / Pin ) = ( Pout / Pout + PLoss )
P d = E b Ia
,
E b = V T - Ia
11.19x103 = ( 120 - Ia(0.061)) ( Ia )
Ia = 98.15 A
η= ( 11.19 KW / ( 11.19 KW + 0.8276 KW ))
η=
93.11 % = 93%
89. An 8-pole triplex wave-wound armature carries a total of 660 amperes. If there are 8
brush arms, calculate the current in each armature conductor.
A. 110 A
B. 66 A
C. 22 A
D. 11 A
Solution:
Ia = 660 A
a = 2m
a = (2) (3)
Ia/conductor = ( Ia / a ) = 660/6 = 110 A
90. Inside a hollow spherical conductor
A. electric field is zero
B. electric field is constant
C. electric field changes with distance from the center of the sphere
D. electric field is unity
91. Residual magnetism is necessary in a
A. separately excited generator
C. both of these
B. self-excited generator
D. none of these
92. Three impedance Zab=4-j3 ohms, Zbc=3+j4 ohms and Zac=10+j0 ohms are
connected in delta across a 220 volts, three phase balanced source. What is the total
power of the circuit?
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
A. 1,839 W
B. 1,836 W
C. 6,130 W
D. 18,392 W
Solution:
PT = ? assume ABC sequence
PT = Iab2 ( Rab ) + Ibc2 ( Rbc ) + Ica2 (Rca)
Iab = | ( Vab / Zab ) | = | (220<0) / (4-j3) | = 44 A
Ibc = | ( Vbc / Zbc ) | = | (220<-120) / (3+j4) | = 44 A
Ica = | ( Vca / Zca ) | = | (220<120) / (10+j0) | = 44 A
PT = (44)2 ( 4 ) + (44)2 (3) + (22)2 (10)
PT = 18,392 W
93. A light source located 2.75 m from a surface produces an illumination of 528 lux on
the surface.Find the illumination if the distance is chaged to 1.55m.
A. 298 lux
B. 1,662 lux
C. 937 lux
D. 168 lux
Solution:
E = K / d2
E1 d 1 = E 2 d 2
E2 = E1 d12
E2 = E1 d12 = (5.28)(2.75)2 / 1.552
E2 = 1662 lux
94. In case of delta connected circuit, when one resistor is open, power will be
A. unaltered
B. reduced to 1/9
C. reduced to 1/16
D. reduced by 1/3
95. Two similar poles, each of 1 Wb, placed 1m apart in ar will experience a replusive
force of_____.
A. 63,000 N
Solution:
B. 796 N
C. 8 x1012 N
D. 63 x10-3 N
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
F = Km1m2 / d2
for MKS
K = 1 / 4πµoµr
K = 1/4π 4π x10-7 ) (1)
K = 63325.74
F = 63325.74 (1)(1) / 12
F = 63 ,328 N = 63 000 N
96. In a Transformer, the core loss is found to be 60 watts at 30 Hz and 90 watts at
40Hz measured at the same maximum flux density. Compute the eddy current and
hysteresis losses at 60 Hz in watts.
A. 90,75
B. 85,60
Solution:
Pcore = Phrs + PEddy
@30Hz
60 = Phrs1 + PEddy1
@40Hz
with respect to frequency change
P = K f2 ---- eddy
K = PEddy1 / f12 = PEddy2 / f22 = PEddy3 / f32
Phrs = K f2
( PEddy1 / PEddy2 ) = ( f1 / f2 )2
( PEddy1 / PEddy2 ) = ( 30 /40 )2
PEddy1 = 9/16 PEddy2
( Phrs1 / Phrs2 ) = ( 30 /40 )
Phrs1 = 3/4 Phrs2
C. 95,69
D. 88,72
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
90 = Phrs2 + PEddy2
60 = Phrs1 + PEddy1
60 = (9/16)PEddy2 + (3/4) Phrs2 -------- eq. 1
90 = Phrs2 + PEddy2
-------- eq. 2
PEddy2 = 40
Phrs2 = 50
( PEddy3 / PEddy2 ) = ( f3 / f2 )2 = ( 60 / 40 )2
PEddy3 = ( 40 ) ( 60 / 40 )2
PEddy3 = 90 W
--------@60Hz
( Phrs3 / Phrs2 ) = ( f3 / f2 ) = ( 60 / 40 )
Phrs3 = ( 50 ) ( 60 / 40 )
Phrs3 = 75 W
---------60Hz
97. Transient current in an RLC circuit is oscillatory when
A. R=0
B. R= 2√L/C
C. R>2√L/C
D. R<2√L/C
98. The current from neutral to ground connection is 12 A. What is the zero sequence
component in phase?
A. 12 A
B. 36 A
Solution:
In = 12
In = Ia + Ib + Ic
from fortescues theorem
Ico = Ibo = Iao = 1/3 ( Ia + Ib + Ic )
= 1/3 ( In )
= ( 1/3 ) ( 12 )
= 12/3
C. 4 A
D. 3 A
REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2018
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
Iao = 4 A
99. With reference to armature windings, wave windings, wave windings are often
called_______ windings.
A. Cascade
B. Series
C. parallel
D. ring
100. This is the compact arrangement of switching devices.
A. Circuit protector
B. Switchboard
C. Switchgear
D. Panelboard