electrical

Three Phase Induction Motor MCQ Questions and Answers Page - 1

1.

An induction motor works with

Answer/ Hint      

Answer : B

Explanation :

2.

The stator frame in an induction  motor is used to

Answer/ Hint      

Answer : A

Explanation :

3.

The frame of an  induction motor is made of

Answer/ Hint      

Answer : C

Explanation :

4.

The  stator core of a 3- phase induction  motor is laminated in order to reduce the

Answer/ Hint      

Answer : A

Explanation :

5.

Use of fractional pitch winding

Answer/ Hint      

Answer : D

Explanation :

6.

If all the stator coils of an induction motor are connected for the same magnetic polarity , there will be formed an equal number of

Answer/ Hint      

Answer : C

Explanation :

7.

The induction motor shaft should be

Answer/ Hint      

Answer : B

Explanation :

8.

The induction motor shaft is made of

Answer/ Hint      

Answer : A

Explanation :

9.

Induction motors normally use diecast aluminum rotor because aluminium is

Answer/ Hint      

Answer : C

Explanation :

10.

In a 3 phase squirrel cage induction motor

Answer/ Hint      

Answer : A

Explanation :

11.

The squirrel cage rotor of a 6-pole induction motor can be used fro ____induction motor

Answer/ Hint      

Answer : C

Explanation :

12.

The squirrel cage induction motors are provided with blades in order to

Answer/ Hint      

Answer : A

Explanation :

13.

The rotor of a 3-phase wound rotor induction motor is provided with

Answer/ Hint      

Answer : B

Explanation :

14.

In a 3-phase slip ring induction motor, the rotor winding terminals are brought out through slip rings to

Answer/ Hint      

Answer : A

Explanation :

15.

The rotor winding for a 3-phase slip ring induction motor having delta connected stator must be connected in

Answer/ Hint      

Answer : B

Explanation :

16.

In a 3-phase slip ring induction motor, brushes are connected to

Answer/ Hint      

Answer : A

Explanation :

17.

In a 3-phase wound rotor induction motor the short circuit gear is used to short circuit the

Answer/ Hint      

Answer : B

Explanation :

18.

Uneven gap in an induction motor is likely to cause

Answer/ Hint      

Answer : C

Explanation :

19.

A smaller air gaps in a polyphase induction motor helps to

Answer/ Hint      

Answer : D

Explanation :

20.

In an induction motor, if the air gap is increased

Answer/ Hint      

Answer : C

Explanation :

21.

Which of the following component is usually fabricated out the silicon steel?

Answer/ Hint      

Answer : C

Explanation :

22.

The shaft of an induction motor is made of

Answer/ Hint      

Answer : C

Explanation :

23.

In an induction motor, no-load the slip is generally

Answer/ Hint      

Answer : A

Explanation :

24.

In medium sized induction motors, the slip ring is generally around

Answer/ Hint      

Answer : C

Explanation :

25.

In squirrel cage induction motors, the rotor slots are usually given slight skew in order to

Answer/ Hint      

Answer : D

Explanation :

26.

In case the air gap in an induction motor is increased

Answer/ Hint      

Answer : B

Explanation :

27.

Slip rings are usually made of

Answer/ Hint      

Answer : C

Explanation :

28.

A 3-phase 440V,50Hz induction motor has 4% slip. The frequency of the rotor e.m.f will be

Answer/ Hint      

Answer : C

Explanation :

29.

If Ns is the synchronous speed and s the slip. Then actual running speed of an induction motor will be

Answer/ Hint      

Answer : C

Explanation :

30.

The efficiency of an induction motor can be expected to be nearly

Answer/ Hint      

Answer : B

Explanation :

31.

The number of slip rings on a squirrel-cage induction motor is usually

Answer/ Hint      

Answer : D

Explanation :

32.

The starting torque of a squirrel-cage induction motor is

Answer/ Hint      

Answer : A

Explanation :

33.

A double squirrel-cage induction motor has

Answer/ Hint      

Answer : C

Explanation :

34.

Star-delta starting of motor is not possible in case of

Answer/ Hint      

Answer : A

Explanation :

35.

The term “cogging” is associated with

Answer/ Hint      

Answer : D

Explanation :

36.

An induction motor with 1000 r.p.m speed will have

Answer/ Hint      

Answer : B

Explanation :

37.

The good power factor of an induction motor can be achieved if the average flux density in the air gap is

Answer/ Hint      

Answer : B

Explanation :

38.

The injected e.m.f in the rotor of an induction motor must have

Answer/ Hint      

Answer : B

Explanation :

39.

Which of the following methods is easily applicable to control the speed of the squirrel-cage motor?

Answer/ Hint      

Answer : A

Explanation :

40.

The crawling in the induction motor is caused by

Answer/ Hint      

Answer : C

Explanation :

41.

The auto-starter (using three auto transformers) can be used to start cage induction motor of the following type

Answer/ Hint      

Answer : C

Explanation :

42.

The torque developed in the cage induction motor with auto starter is

Answer/ Hint      

Answer : C

Explanation :

43.

When the equivalent circuit diagram of double squirrel-cage induction motor is constructed the two cages can be considered

Answer/ Hint      

Answer : B

Explanation :

44.

It is advisable to avoid line-starting of induction motor is possible by which of the following methods

Answer/ Hint      

Answer : A

Explanation :

45.

Stepless speed control of induction motor is possible by which of the following methods?

Answer/ Hint      

Answer : B

Explanation :

46.

Rotor rheostat control method of speed control is used for

Answer/ Hint      

Answer : B

Explanation :

47.

In the circle diagram foe induction motor, the diameter of the circle represents

Answer/ Hint      

Answer : B

Explanation :

48.

For which motor the speed can be controlled from rotor side/

Answer/ Hint      

Answer : B

Explanation :

49.

If any two phases for an induction motor are interchanged

Answer/ Hint      

Answer : A

Explanation :

50.

An induction motor is

Answer/ Hint      

Answer : C

Explanation :

51.

The maximum torque in an induction motor depends upon

Answer/ Hint      

Answer : D

Explanation :

52.

In three-phase squirrel-cage induction motor

Answer/ Hint      

Answer : B

Explanation :

53.

In a three-phase induction motor, the number of poles in the rotor winding is always

Answer/ Hint      

Answer : D

Explanation :

54.

DOL staring of induction motors is usually restricted to

Answer/ Hint      

Answer : A

Explanation :

55.

The speed of squirrel-cage induction motor can be controlled by all of the following expect

Answer/ Hint      

Answer : C

Explanation :

56.

The “crawling” in an induction motor is caused by

Answer/ Hint      

Answer : D

Explanation :

Three Phase Induction Motor MCQ Questions and Answers Page - 1
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