An induction motor which connects with a 3-phase supply called 3-stage induction motor. Example supporters,blowers, cranes,traction .It really is a ac engine. The main drawback of DC motors may be the existence of commutator and brushes, which require regular maintenance and we can not use DC motor in explosive and dirty environment. But induction motors are cheaper,tough,lighter,smaller,require much less maintenance and may use in dirty and explosive environment. Slip 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 various starting and braking condition.
Important starting methods are
Auto transformer starter
Ac voltage controller starter
Rotor three phase ac induction motor china resistance starter
Important braking methods are
Plugging or invert voltage braking
But one thing rate control technique of induction motor is important
Stator voltage control
Slip power recovery
Rotor resistance control