FEB 2018

ELECTRICIAN THEORY

SEMESTER-4

PART-1

1. If a slot consists of one coil

side then the winding is called-
a) Double layer winding

b) Full pitch winding

c) Single layer winding

d) Short pitch winding

Answer:- b) Full pitch winding

2. A capacitor start, capacitor run

single phase induction motor is

basically a

a) AC series motor

b) DC series motor

c) 2 phase induction motor

d) 3 phase induction motor

Answer:- c) 2 phase induction

                     motor

3. The starting torque of a capacitor

start motor is -
a) Zero

b)Low

c) Same as rated torque

d) More than rated torque

Answer:- b)Low

4. The starling capacitor of a single phase motor is - .
a) Electrolytic capacitor

b) Ceramic capacitor

c) Paper capacitor

d) None of the above.

Answer:- a) Electrolytic capacitor

5. The motor used in household

refrigerators is -
a) DG series motor

b) DC shunt motor

c) Universal motor

d) Single phase induction

     motor.

Answer:- d) Single phase

                     induction motor

6. A capacitor start single phase

induction motor will usually

have a power factor of
a) Unity

b) 0.8 leading

c)0.6 leading

d) 0.6 lagging

Answer:- d) 0.6 lagging

7. The short coming of repulsion

motor is -
a) Variation of speed with load

b) Low power factor

c) Tendency to spark at brushes

d) All of these

Answer:- d) All of these

8. A ceiling fan of 1400 mm sweep

will have motor rating of
a) 10 to 15 waits

b) 50 to 70 watts

c) 120 to 180 watts 

b) 250 to 500 watts.

Answer:- c) 120 to 180 watts 

9. Which of the following

applications would need the

smallest size of motor?
a) Domestic motor

b) Electric clock

c) Table fan

d) Sewing machine

Answer:- b) Electric clock

10. Which of the following is

not a bio-mass source?

a) Gobar gas

b) Coal

c) Wood

d) Nuclear energy

Answer:- d) Nuclear energy

11. The source of energy of

the sun is__

a) Nuclear fission

b) Chemical reaction

c). Nuclear fusion

d) Photoelectric effect

Answer:-c). Nuclear fusion

12. Which motor would you

select for vacuum cleaners?
a) Universal motor .

b) Repulsion motor

c) Hysteresis motor

d) Reluctance motor.

Answer:- a) Universal motor

13. The advantage of*salient

poles in an alternator is -

a) Reduce noise

b) Reduced windage loss

c) Adoptability to low and

    medium speed operation

d) Reduce bearing loads

    and noise.

Answer:- c) Adoptability to low

and medium speed operation

14. Major share of power

generated in India is through

which means-
a) Hydroelectric power plants

b) Nuclear power plants

c) Thermal power plants

d) Gas turbine power plants

Answer:- ) Thermal power plants

15. A three phase alternator has

a phase sequence of RYB for is

three output voltages for
clockwise rotation. Now if the

alternator is rotated anticlockwise,

the phase sequence will be

a) RYB

b) RBY

c) BYR

d) None of these

Answer:- b) RBY

16. In an alternator, voltage

drops occurs in -

a) Armature resistance only

b) Armature resistance and

      leakage reactance

c) Armature resistance, leakage

 reactance and armature reaction

d) Armature resistance, leakage

reactance, armature reaction and earth

Answer:- c) Armature resistance,

 leakage reactance and armature

 reaction

17. The power Factor of an alternator

depends on -

a) Load

 b) Speed of rotor

c) Core losses

d) Armature losses

Answer:- a) Load

18.  The frequency of voltage

generated by. an alternator having

8 poles and rotating at 250 rpm is

a) 60 Hz

b)50Hz
c)25Hz

d) 16 2/3 Hz

Answer:- d) 16 2/3 Hz

19. A winding is having number of

slots is greater than number of polos,

 then this winding is
called-

a) Concentrated winding

b) Distributed winding

c) Full pitch winding

d) Integrated slot winding

Answer:- b) Distributed winding

20. Synchronous motor can

operate at -

a) Lagging power factor only

b) Leading power factor only

c) Unity power factor only

d) Lagging, leading and unity

   power factor only

Answer:- d) Lagging, leading

and unity power factor only

21. The damping winding in a

synchronous motor is generally used

a) To provide starting torque only

b) To reduce noise level

c) To reduce eddy currents

d) To prevent hunting and provide

the starting torque

Answer:- d) To prevent hunting and

provide the starting torque

22. The back emf set up in ihe stator

of a synchronous motor will depend on

a) Rotor speed only

b) Rotor excitation only

c) Rotor excitation and rotor speed       

d) Coupling angle, rotor speed and

Answer:- b) Rotor excitation only

23. In a synchronous motor, damper

winding is provided to -

a) Stabilize rotor motion

b) Suppress rotor oscillations

c) Develop necessary starting torque    

d) Both (a) & (c)

Answer:- d) Both (a) & (c)

24. Advantage of 'hydro-electric power

station is -

a) Low operating cost

b) Free from pollution problems

c) No fuel transportation problems       

d) All of these

Answer:- d) All of these

25. An Auto-transformer (which has

only one winding) may be used as a
a) Step-Up Transformer

b) Step-Down Transformer

c) Both (a) & (b)

d) None of the above

Answer:- c) Both (a) & (b)