An induction electric motor which connects with a 3-stage supply called 3-phase induction motor. Example supporters,blowers, cranes,traction .It is a ac motor. The main drawback of DC motors is the three phase ac induction motor existence of commutator and brushes, which require regular maintenance and we can’t use DC motor in explosive and dirty environment. But induction motors are cheaper,tough,lighter,smaller,require less maintenance and can use in dirty and explosive environment. Slide s is the imp element in this kind 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 reverse voltage braking
Dynamic braking
But one thing quickness control technique of induction electric motor is important
Pole changing
Stator voltage control
V/f control
Slip power recovery
Rotor resistance control