How is a three phase cage induction motor self starting?

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How is a three phase cage induction motor self starting?

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Answer :

Any type of induction motor is self starting.

Because the reason for torqe production require two flux displaced by some angle theta.If theta is constant with time then torqe will be constant;if theta is varying then torqe also pulsating.

In induction motor this angle theta is not pulsating.so it is self starting 
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