Can you please provide me the previous year question paper of Gujarat Technical University (GTU) of Automobile Engineering Sem. III Electrical Machines And Electronics Exam???

Here is the previous year question paper of Gujarat Technical University (GTU) of Automobile Engineering Sem. III Electrical Machines And Electronics Exam

Q.1 (a) Draw and explain the construction of a dc generator. Mention the material
used and functions of :
1) Yoke
2) Poles
3) Armature
07

(b) A 4-pole lap-wound, shunt generator has armature with 750 conductors. The
flux per pole is 20 mWb and the generator supplies 100 nos. of 220 V, 60 W
lamps. Determine the speed of the generator. Armature and field winding
resistances are 0.1 , and 100 , respectively.
07

Q.2 (a) Armature resistance of a d.c. shunt motor is 5 ,. On full-load it runs at 1600
r.p.m. taking an armature current of 10 A from 220 V supply. Determine fullload
torque and starting torque.
07

(b) Compare rheostatic control and field control methods for speed control of
d.c. shunt motor.
07

OR
(b) Draw and explain the construction of a three point starter for d.c. shunt
motor. Explain the function of Hold-on Coil and Overload Coil in it.
07
Q.3 (a) Explain the production of rotating magnetic field for a 3-ph. Induction motor
using analytical method and phasor diagrams at θ = 0°and θ = 60°.
07

(b) A 10 h.p., 440 V, 3-ph., 4-pole induction motor works on 50 Hz supply.
Determine:
1) Synchronous speed
2) Motor speed at a slip of 5 %
3) Frequency of current in rotor circuit when slip is 7.5 %
4) Rotor speed when slip is 4 %.
07

OR
Q.3 (a) Explain the principle and working of Capacitor Start Capacitor Run 1-ph.
Induction Motor. What are its advantages and applications?
07
(b) Draw the construction of an alternator. What do you mean by synchronizing
of an alternator? What are the conditions to be fulfilled for proper
synchronization of alternators?
07

Q.4 (a) Explain the working principle of a transformer. Draw the construction of
shell type and core type transformer.
07

2
(b) With the help of layout of an electrical power system, explain the
transmission and distribution of 3-ph. a.c. power.
07

OR
Q.4 (a) What is the meaning of tariff? What are the criteria for deciding tariff?
Explain the principle of power factor improvement.
07
(b) Find the most economical power factor for a HT consumer having tariff as
follows. The tariff is Rs. 100 per KVA per annum of maximum demand plus
a flat rate per kWh for a HT consumer. Assume additional cost of capacitors
for power factor improvement of Rs. 80 per KVAR. Rate of interest and
depreciation is together to be taken as 10 %.
07

Q.5 (a) What is the purpose of substations in electrical power system? Explain
briefly the function of following equipments in a substation:
1) Bus-bar
2) Circuit Breaker
3) Isolator
4) Lightning Arrester
5) Insulator
07

(b) Draw the circuit diagram for full-wave bridge rectifier. Explain its working
during positive and negative cycles using the waveforms of voltage on
transformer secondary and load voltage.
07

OR
Q.5 (a) Give the symbol Boolean expression and logical operation for the following
logic gates:
1) NOT
2) AND
3) OR
4) NAND
5) NOR
6) Exclusive OR
7) Exclusive NOR
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(b) With reference to architecture of 8085 microprocessor, explain the
following:
1) General purpose registers
2) Accumulator
3) ALU
4) Program Counter
07