Polyphase Induction Motors MCQ - Electrician (Set-1) with Answers

Polyphase Induction Motors MCQ - Electrician (Set-1) with Answers

61) If single phasing occurs during running of a 3 phase motor, what is the effect on motor performance ?

Answer is:

Continue to run on 2 phases, draws excess current, winding likely to burn

62) You have to change the defective induction motor of a machine. The available motor is of a higher capacity than the existing one. What is the effect of using a higher capacity motor ?

Answer is:

The efficiency and the power factor will become low

63) The synchronous speed of an induction motor refers to the speed of the

Answer is:

rotating magnetic field

64) Calculate slip of an induction motor if it has 4 poles, 50Hz, rotor speed is 1400 rpm.

Answer is:

6.6%

65) in a 3-phase motor the rotating magnetic field is displaced at an angle of

Answer is:

120 degree

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