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

There are 2 types of IM.

Squirrel cage IM
Slip ring IM
There are numerous 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 rate control technique of induction motor is important

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