Recruitment Test of BIFPCL-2019
Post: Assistant Engineer (Electrical)
1. Find Req in the circuit.
60Ω
12Ω
2.5Ω
6Ω
80
Ω
+
20Ω
15Ω
−
35 V
Req
2. For the electronic circuit shown in the figure bellow, calculate
the maximum value of RB, when Vin of 5V drives the
transistor into saturation. Given, bDC = 200, VCE(sat) = 0 V
and VBE = 0.7 V.
VCC
+ 10 V
RC
1 kΩ
Vout
RB
Vin
b DC= 200
3. Assuming an ideal Op-Amp,
Calculate the current I L in the following circuit:
5 kΩ
+12 V
−
10 kΩ
Vo
+
iL
-12 V
+
−
5V
40 kΩ
20 kΩ
4. A three-phase 460 V, 100 HP, 50 Hz, 4-pole induction motor
deliver rated output power at a slip 0.5. Determine
(a) speed of rotating air-gap field and
(b) frequency of rotor current.
5. A single-phase 5 KVA, 200/400 V, 50 Hz, transformer has
150 W core loss and 175 W full load Cu loss. Calculate
the efficiency of the transformer at 75% loading with
0.7 lagging power factor.
6. Find the output of the following system.
Low Pass
Filter
[A+m(t)]cos wct
DC Blocker
Output
cos wct
7. A resistor R, inductor L, capacitor C = 100 μF are connected
in series with supply voltage v = 282.80 sin (500t) V and current
flow through the circuit is i = 5.65 sin (500t - 36.87°) A.
Find the value of R and L.
8. A 13.8 kV alternator has a ground relay pick up current of 1 A,
a neutral resistance of 30 Ω and a neutral CT rated at 200/5 A.
Determine the percentage of alternator winding that remain
unprotected.
9. A synchronous generator is connected to a synchronous motor
by a line with impedance of j0.1 p.u. The sub-transient reactance
of both generator and motor is j0.2 p.u. If a bolted three phase to
ground fault is occurred at the motor terminal, determine the
fault MVA. Assume that, the voltage at the motor terminal is
0.9 p.u. and system base is 100 MVA.
10. Consider a 3 bus power system where bus-1 is slack bus,
bus-2 is load bus and bus-3 is generator bus. The elements
of Jacobean matrix using full Newton Raphson Method are
found to be J11 = 80, J12 = - 40, J13 = 10, J21 = - 40, J22 = 60,
J23 = 20, J31 = 25, J32 = 30, J33 =75. If decoupled load flow
method is used, what are the elements of the modified
Jacobean Matrix?