AC THREE PHASE MOTOR - Quiz

1) Calculate the number of coils per phase per pair of poles of 3 phase motor having 2 pole, 24 slots,12 coils?

1 2 3 4

2) What is the synchronous speed of a A.C 3 phase induction motor having 6 poles at a frequency of 50 Hertz

800 rpm 1000 rpm 1200 rpm 1440 rpm

3) Calculate the percentage slip in a 3 phase induction motor having 6 poles with a frequency of 50 Hertz rotating with actual speed of 960 rpm?

0.02 0.03 0.04 0.05

4) What is the rotor frequency of a 3 phase squirrel cage induction motor at the time of starting?

Equal to supply frequency 3 times less than supply frequency 3 times more than supply frequency Root(3) times less than supply frequency

5) How the voltage is received in the rotor of induction motor?

Direct connection from stator Due to back emf produced in stator Direct connection to rotor from supply By the transformer action of stator and rotor