An induction engine which connects with a 3-stage supply called 3-stage induction motor. Example fans,blowers, cranes,traction .It 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 dirty environment. But induction motors are cheaper,rugged,lighter,smaller,require much less maintenance and will use in dirty and explosive environment. Slide s may be the imp factor in this type of motor.

There are 2 types of IM.

Squirrel cage IM
Slip ring IM
There are numerous starting and three phase ac induction motor china 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 swiftness control technique of induction engine is important

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