1. What is the difference between ac induction motor
and ac synchronous motor?

Answer Posted / amritpal singh sidhu

1. Synchronous motor runs at synchronous speed but the
induction moror can't, if it does so then it will stop
because the rotor conductors will not cut the magnetic
field & induction principle will fails.
2. Synchrounous motor can improve power factor but
induction motor can't.
3. Synchrounous motor is costly as compared to induction
motor.
4. Synchrounous motor has two types excitations but in
induction motor has only one type excitation.
5. Synchronous motor can't run at other speed without
synchronous speed, if it does so then it will fall out of
synchronism & will stop.
6. There is requirement of any auxilary help for starting
the synchronous motor like pony motor,with the help of
manual rotation, by inserting the copper cage into its own
rotor(means starting as squirrel cage motor), but there is
no requirement of any help to start the induction motor.

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