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

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

31) The purpose of a back-up fuse is to provide protection against :

Answer is:

short-circuit

32) A 4-pole, 3-phase, 50 Hz motor's speed is 95% of its synchronous speed then the actual speed of the motor is :

Answer is:

1425 r.p.m.

33) The induction motor of a pump is run at a supply voltage 30% lesser than the normal voltage (415 V). The pump starts to work. After some time what possibly can happen ?

Answer is:

The motor will become hot and will be damaged

34) The purpose of adding a rheostat to slip-ring induction motor is to :

Answer is:

decrease the starting current so that the starting torque may increase

35) The rotor current frequency of a slip-ring induction motor depends on :

Answer is:

amount of slip

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