An induction electric motor which connects with a 3-phase supply called 3-phase induction motor. Example fans,blowers, cranes,traction .It is a ac engine. The primary drawback of DC motors is the existence of commutator and brushes, which require regular maintenance and we can not use DC motor in explosive and dirty environment. But induction motors are cheaper,durable,lighter,smaller,require less maintenance and can use in dirty and explosive environment. Slide s may be the imp three phase ac induction motor china aspect in this kind of motor.

There are ER series helical geared motor2 types of IM.

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

Important starting methods are

Star-delta starter
Auto transformer starter
Ac voltage controller starter
Rotor resistance starter
Important braking methods are

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

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