An induction motor which connects with a 3-stage supply called 3-phase induction motor. Example supporters,blowers, cranes,traction .It really is a ac engine. The primary drawback of DC motors may be the existence of commutator and brushes, which require regular maintenance and we can’t use DC engine in explosive and filthy environment. But induction motors are cheaper,rugged,lighter,smaller,require less maintenance and will use in dirty and explosive environment. Slide s is the imp element in this kind of motor.

There are 2 types of IM.

Squirrel cage IM
Slip ring IM
There are numerous starting and braking condition.

three phase ac induction motor important starting methods are

Star-delta starter
Auto transformer starter
ER series helical geared motorAc voltage controller starter
Rotor resistance starter
Important braking methods are

Regenerative braking
Plugging or invert voltage braking
Dynamic braking
But one thing rate control technique of induction electric motor is important

Pole changing
Stator voltage control
V/f control
Slip power recovery
Rotor resistance control