R13
Code: 13A02402
B.Tech II Year II Semester (R13) Supplementary Examinations December/January 2015/2016
CONTROL SYSTEMS ENGINEERING
(Electrical and Electronics Engineering)
Time: 3 hours
Max. Marks: 70
PART – A
(Compulsory Question)
1
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
*****
Answer the following: (10 X 02 = 20 Marks)
List all electrical analogs of rotational mechanical systems using force-current analogy.
A closed loop control system has an open loop gain of 100. Its feedback loop has a gain of 0.005. Find
its sensitivity for negative feedback.
Write the expressions for the response of first order system to the unit step input signal and unit ramp
input signal in time domain.
What is a type 1 system? What is its steady state error for unit ramp input?
Determine the stability of the system with the characteristic equation
Discuss the effect of addition of open loop poles on the root loci.
Define gain margin.
Define gain cross-over point.
Define the state of a system.
Derive the response of unforced system.
PART – B
(Answer all five units, 5 X 10 = 50 Marks)
UNIT – I
2
Find the transfer function matrix for the two input two output system shown in the figure below.
-1
1
x14
1
R1
x12
G1
x13
G3
G2
C1
x11
H1
H2
-1
R2
1
1
x24
3
G6
G5
G4
x21
x22
x23
C2
OR
Develop a signal flow graph for the motor shown in figure below with the given constants. Find the
transfer function
using Mason’s formula.
ra
Ιa
La
km
J
Va
Ιf =
Constant
f
Eb
m
Where ra is armature resistance; La is armature inductance; J is motor inertia; f is motor friction and km
is motor constant.
Contd. in page 2
Page 1 of 2
R13
Code: 13A02402
UNIT – II
4
A unity feedback system has an open loop transfer function
Determine its damping ratio,
peak overshoot and time required to reach the peak output. Now a derivative component having transfer
function of is introduced in the system. Discuss its effect on the values obtained.
OR
5
A unity feedback system having open loop transfer function as
, determine: (i) Type
of system. (ii) kp, kv and ka. (iii) Steady state error for parabolic input.
UNIT – III
6
Sketch the root locus for a unity feedback system having
OR
7
The open loop transfer function of a unity feedback system is given by
. Sketch the
root locus for
UNIT – IV
8
Consider the transfer function
. Comment on stability of the system using the
sketch of its Nyquist plot.
9
OR
Explain Nyquist criterion. Write the procedure for determining Nyquist plot.
UNIT – V
10
Consider the electric circuit shown in the figure below, where e1 and e2 are the inputs and v1, v2, v3 are
outputs. Choosing i1, i2 and i3 as the state variables, determine the system equations and write the
state model.
v2
v1
R1
R2
L1
L2
C
i2
v3
e2
e1
OR
11
Consider the system
where
*****
Page 2 of 2
Find
and the solution for
R13
Code: 13A02403
B.Tech II Year II Semester (R13) Supplementary Examinations December/January 2015/2016
ELECTRICAL POWER GENERATING SYSTEMS
(Electrical and Electronics Engineering)
Time: 3 hours
Max. Marks: 70
PART – A
(Compulsory Question)
1
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
*****
Answer the following: (10 X 02 = 20 Marks)
Draw the line diagram for coal and ash handling arrangement.
Differentiate between the natural and forced draught fans.
List the factors for the selection of site for hydro electric power plants.
Write the functions of moderator and control rods.
Write about different types of solar energy collecting systems.
Define pitch angle.
Write Economic and environmental aspects for biogas plants.
Define principle of tidal energy generation.
Define plant use factor, demand factor and load factor.
Write different types of tariff methods.
PART – B
(Answer all five units, 5 X 10 = 50 Marks)
UNIT – I
2
(a)
(b)
3
(a)
(b)
Draw labeled schematic block diagram of thermal power plant showing all the systems
Explain about Economizer
OR
Explain Superheaters and reheaters.
Write about different types of turbines used in thermal power plants
UNIT – II
4
(a)
(b)
5
(a)
(b)
Classify hydroelectric power plants in different ways.
Explain main parts of a Nuclear reactor.
OR
Draw schematic arrangement of a nuclear power station and explain each part.
Explain Pressurized Water Reactor.
UNIT – III
6
(a)
(b)
7
Explain the role and potentiality of solar power in India.
Explain I-V characteristics of PV cells.
OR
Explain horizontal and vertical axis wind turbines with their operation and characteristics.
UNIT – IV
8
(a)
(b)
9
(a)
(b)
Explain Bio-gas power plant with block diagram.
What is meant by anaerobic digestion? What are the factors which affect biodigestion? Explain briefly.
OR
Explain the concept of how geothermal energy is produced.
Explain the operation of single pool modulated tidal system.
UNIT – V
10
(a)
(b)
11
(a)
(b)
Write the procedural steps to draw the load duration curve
A generating station supplied the following loads: 175 MW, 100 MW, 80 MW, 50 MW and 4 MW. The
station has a maximum demand of 225 MW. The annual load factor of the station is 45%, calculate:
(i) The number of units supplied annually. (ii) The diversity factor. (iii) The demand factor.
OR
Explain two part tariff and three part tariff methods.
Explain flat rate tariff and block rate tariff methods.
*****
R13
Code: 13A02404
B.Tech II Year II Semester (R13) Supplementary Examinations December/January 2015/2016
ELECTRICAL MACHINES – II
(Electrical and Electronics Engineering)
Time: 3 hours
Max. Marks: 70
PART – A
(Compulsory Question)
1
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
*****
Answer the following: (10 X 02 = 20 Marks)
Distribution transformers are always designed for lower magnetic losses. Why?
For a load of same magnitude, the efficiency of a transformer will be more for 0.8 leading power factor
load than 0.8 lagging power factor load. Comment.
Give the factors affecting the load sharing among the transformers operating in parallel.
Comment on the size, efficiency and voltage regulation of autotransformer and a two winding
transformer.
Why a bank of single phase transformers connected in delta is preferred over a three phase delta
connected transformer?
A 3-phase, 50 Hz squirrel cage induction motor runs at 4% slip. What will be frequency of rotor
currents?
What is Cogging in an induction motor?
The starting current and starting torque of induction motor increases with decrease in supply frequency.
How is the starting current and starting torque related to the supply frequency?
In what ratio the line current and starting torques are reduced with star-delta starting?
On what factors does the speed of a induction motor depend?
PART – B
(Answer all five units, 5 X 10 = 50 Marks)
UNIT – I
2
(a)
(b)
3
(a)
(b)
With relevant phasor diagrams, explain the operation of a practical single phase transformer operating
on lagging and leading power factor loads.
A single phase 50 Hz transformer has 440 turns on the primary and 110 turns on the secondary winding
takes a no-load current of 5 A at 0.2 power factor lagging. If the secondary supplies a current of 120 A
at a power factor of 0.8 lagging. Estimate the current taken by the primary. Take secondary voltage as
reference.
OR
In a transformer, derive the condition for maximum efficiency and thus find the load current at which the
efficiency is maximum.
A 200 kVA 1-phase transformer is in operation continuously. For 8 hours in a day, the load is 160 kW at
0.8 pf. For 6 hours, the load is 80 kW at unity pf and for the remaining period of 24 hours it runs on
no-load. Full-load copper losses are 3.02 kW and the iron losses are 1.6 kW. Find all-day efficiency.
UNIT – II
4
(a)
(b)
5
(a)
(b)
Derive an expression for saving of copper when an autotransformer is used.
Obtain the approximate equivalent circuit of a 200 / 2000 V single-phase 30 kVA transformer referred to
200 V side using the following test results:
OC Test: 200 V 6.2 A 360 W on l.v. side
SC Test: 75 V
18 A 600 W on h.v. side
OR
Two transformers operating in parallel have different reactance to resistance ratios. Show that one
transformer operates at a better power factor than the other.
With a neat circuit diagram, describe back-to-back test conducted on two identical transformers.
Contd. in page 2
Page 1 of 2
R13
Code: 13A02404
UNIT – III
6
7
(a)
(b)
Explain Scott connection with neat diagrams. With necessary phasor diagrams, prove that a threephase system can be established from a two-phase system using T-T connection.
OR
Explain with the help of suitable diagrams, how rotating magnetic field is produced in a 3-phase
induction motor.
Why the air-gap between stator core and rotor is made as small as possible?
UNIT – IV
8
(a)
(b)
9
(a)
(b)
Establish a relation between full load torque and maximum torque of a three phase induction motor.
A 6-pole, 3-phase, 50 Hz induction motor develops maximum torque of 300 N-m at a speed of 960 rpm.
Determine the torque developed by the motor at 5% slip. The rotor resistance per phase is 0.6 ohm.
OR
Describe the principle of operation of three phase induction motor. What are the operational similarities
and differences between transformers and induction motors?
The power input to the rotor of a 440 V, 50 Hz, 3-phase, 6-pole induction motor is 50 kW. It is observed
that the rotor e.m.f makes 120 complete cycles per minute. Calculate: (i) Slip. (ii) Rotor speed. (iii) Rotor
copper loss/phase. (iv) Rotor resistance per phase.
UNIT – V
10
(a)
(b)
11
(a)
(b)
Explain the consequent pole technique for controlling speed of three phase induction motor.
Explain the cascade arrangement for controlling the speed of three phase induction motor. Derive the
equation for speeds at which the cascade set operates.
OR
List out the merits and demerits of rotor resistance control over other methods of controlling the speed
of three phase induction motor.
With a neat sketch, explain the operation of star-delta starter. Also, mention its limitations.
*****
Page 2 of 2
R13/SS
Code: 13A04303
B.Tech II Year II Semester (R13) Supplementary Examinations December/January 2015/2016
SWITCHING THEORY & LOGIC DESIGN
(Common to EEE and ECE)
Time: 3 hours
Max. Marks: 70
PART – A
(Compulsory Question)
1
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
*****
Answer the following: (10 X 02 = 20 Marks)
State and Prove consensus theorem.
Find the 2’s complement of representation of -9.
Design a XOR gate using minimum number of NAND gates.
Find the minimum number of literals for the following function using 2 variable Karnaugh Map.
F = =∑m (1) + d (3).
d - Don’t care.
Write the sum and carry expression for half adder.
Implement the function F =∑m (0, 2) using a 2 × 4 decoder.
Write the characteristic equation for JK Flip-flop.
How many states are there in a n-bit ring counter?
Compare PROM & PAL.
What is meant by cycle in asynchronous circuits?
PART – B
(Answer all five units, 5 X 10 = 50 Marks)
UNIT – I
2
(a)
(b)
3
(a)
(b)
Express the following function F = xy + x’ y in a product of max-terms.
Check if NOR gate is associative or not.
OR
Show that a positive logic NAND gate is a negative logic OR gate
Obtain the truth table of the following function and express in sum of min-terms and product of maxterms: F = (A’ + B).(B’ + C).
UNIT – II
4
(a)
(b)
5
Simplify the Boolean function using K map technique:
F = π M (3, 4, 6, 7, 11, 12, 13, 14, 15).
F = ∑m (0, 1, 2, 4, 5, 6, 8, 9, 12, 13, 14).
OR
Simplify the following Boolean function using tabulation method:
F = ∑m (0, 1, 2, 3, 5, 7, 8, 10, 14, 15).
UNIT – III
6
7
(a)
(b)
Design a 4-Bit Magnitude comparator using logic gates.
OR
Implement the function F = ∑m (0, 1, 2, 4, 5, 8, 11, 12, 15) using 8:1 multiplexer.
Design a half subtractor using logic gates.
UNIT – IV
8
9
Design a 4 bit universal shift register with neat diagram.
OR
Design a 3 bit synchronous up counter using T Flip-flops.
UNIT – V
10
11
Implement the following functions using PLA with three inputs, four product terms and two outputs.
F1 (A, B, C) = ∑m (3, 5, 6, 7), F2 (A, B, C) = ∑m (0, 2, 4, 7).
OR
Implement the switching function F = ∑m (1, 3, 5, 7, 8, 9, 14, 15) by a static hazard free two level ANDOR network.
*****
R13
Code: 13A04407
B.Tech II Year II Semester (R13) Supplementary Examinations December/January 2015/2016
ANALOG ELECTRONIC CIRCUITS
(Electrical and Electronics Engineering)
Time: 3 hours
Max. Marks: 70
PART – A
(Compulsory Question)
1
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
*****
Answer the following: (10 X 02 = 20 Marks)
Write any two basic differences between BJT RC coupled and FET RC coupled amplifiers.
Give the significance of gain bandwidth product.
Draw current shunt feedback amplifier.
Write any two characteristics of negative feedback.
Write any two main applications of crystal oscillator.
Give the balancing equation of Wein bridge oscillator.
What is the significance of heat sinks in power amplifiers?
What is the efficiency of class A amplifier?
Define clipper and give its applications.
What is Schmitt trigger?
PART – B
(Answer all five units, 5 X 10 = 50 Marks)
UNIT – I
2
Explain the working principle of BJT RC coupled amplifier.
OR
Draw cascade amplifier circuit and derive expression for gain.
3
UNIT – II
4
(a)
(b)
5
Write the characteristics of negative feedback in amplifiers.
Explain about voltage series feedback amplifiers.
OR
Write short notes on current feedback amplifiers.
UNIT – III
6
(a)
(b)
7
(a)
(b)
Explain RC phase shift principle.
Explain RC phase shift oscillator with a neat circuit diagram.
OR
Explain the principle of tuned oscillators.
Write an expression for frequency of tuned oscillators and explain.
UNIT – IV
8
Explain the principle of operation of complimentary symmetry and give its drawbacks.
OR
Explain principle of class A amplifier and derive expression for efficiency.
9
UNIT – V
10
11
(a)
(b)
Explain high pass RC circuit.
Explain diode clamper circuit with suitable wave forms.
OR
Explain Monostable Multivibrator principle with a neat sketch.
*****