An induction motor which three phase ac induction motor china connects with a 3-phase supply called 3-phase induction motor. Example followers,blowers, cranes,traction .It is a ac electric motor. The main drawback of DC motors may be the existence of commutator and brushes, which require frequent maintenance and we can’t use DC electric motor in explosive and dirty environment. But induction motors are cheaper,durable,lighter,smaller,require much less maintenance and may use in dirty and explosive environment. Slip s may be the imp aspect 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 electric motor is important
Pole changing
Stator voltage control
V/f control
Slip power recovery
Rotor resistance control