Multiple Choice Question (MCQ) of Induction Motors page-1

1.At zero in an induction motor

a) Motor runs as a generator
b) Motor does not run
c) The motor runs an at synchronous speed
d) Slip produced is zero

Ans: (b)

2. In an induction motor, rotor slots are usually not quite parallel to the shaft but are given a slight skew

a) To reduce the magnetic hum
b) To reduce the locking tendency of the rotor
c) Both (a) and (b) above
d) To increase the speed of the motor

Ans: (c)

3. The field of an induction motor rotor rotates relative to the stator at

a) Rotor speed
b) Synchronous speed
c) Slip speed
d) Very low speed

Ans: (b)

4. In an induction motor, rotor runs at a speed

a) Equal to the speed of stator field
b) Lower than the speed of stator field
c) Higher than the speed of stator field
d) Having no relation with the speed of stator field

Ans: (b)

5. Starters are used in induction motor because

a) Its starting torque is high
b) It is run against heavy load
c) It can not run in reverse direction
d) Its starting current is five times or more than its rated current

Ans: (d)

6. When an induction motor runs at rated load and speed, the iron losses are

a) Negligible
b) Very heavy
c) Independent of supply frequency
d) Independent of supply voltage

Ans: (a)

7. By synchronous wattage of an induction motor is meant

a) Stator input in watts
b) Rotor output in watts
c) Rotor input in watts
d) Shaft output in watts

Ans: (c)

8. The emf induced in the rotor of an induction motor is proportional to

a) Voltage applied to stator
b) Relative velocity between flux and rotor conductors
c) Both (a) and (b) above
d) Slip

Ans: (c)

9. The synchronous speed of an induction motor is defined as

a) Natural speed at which a magnetic field rotates
b) The speed of a synchronous motor
c) The speed of an induction motor at no load
d) None of these

Ans: (a)

10. The starting torque of an indication motor is maximum when

a) Rotor resistance equals rotor reactance
b) Rotor resistance is twice the rotor reactance
c) Rotor resistance is half the rotor reactance
d) Rotor resistance is R₂ times the rotor reactance

Ans: (a)

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Multiple Choice Question (MCQ) of Induction Motors page-1

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