An induction engine which connects with a 3-stage supply called 3-phase induction motor. Example supporters,blowers, cranes,traction .It is a ac electric motor. The main 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 less maintenance and may use in dirty and explosive environment. Slide s is the imp aspect 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 three phase ac induction motor methods are
Star-delta starter
Auto transformer starter
Ac voltage controller starter
Rotor resistance starter
Important braking methods are
Regenerative braking
Plugging 
or reverse voltage braking
Dynamic braking
But one thing velocity control technique of induction engine is important
Pole changing
Stator voltage control
V/f control
Slip power recovery
Rotor resistance control
