An induction engine which connects with a 3-stage supply called 3-phase induction motor. Example fans,blowers, three phase ac induction motor china cranes,traction .It really is a ac motor. The main drawback of DC motors may be the presence 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,durable,lighter,smaller,require much less maintenance and may use in filthy and explosive environment. Slide s is the imp element in this type 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