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

There are 2 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 speed control technique of induction engine is important

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