AC THREE PHASE MOTOR - Quiz

1) Why slip ring induction motor is fitted with wound rotor?

To reduce the slip To control the speed To reduce the losses To get high starting and running torque

2) What is the function of timer in automatic star delta starter?

Trip at over load Switch ON at pre set time Change from star to delta Switch OFF at pre set time

3) Which instrument is used to measure insulation resistance of a 3 phase induction motor?

Megger Multimeter Shunt type ohmmeter Series type ohmmeter

4) What is the starting current of an A.C 3 phase induction motor?

1 to 2 times of full load current 2 to 3 times of full load current 4 to 5 times of full load current 5 to 6 times of full load current

5) Which method is used to control the speed of 3 phase induction motor from stator side?

By cascade operation By rotor rheostat control By injecting emf in rotor circuit By changing the applied frequency