Speed control of three phase induction motor

Speed control of three phase induction motor is explained in this video. Induction motors are the most poplars motors due to many advantages like they are robust, cheap in coast, require less maintenance, can work in polluted environment. The methods used to speed controls are; 1) Stator Control a) By controlling voltage though auto transformer b) By controlling voltage through Rheostat c) By controlling Voltage through ac voltage controller d) By controlling frequency e) Constant V/F control g) By changing number of Poles 2) Rotor Control a) Rotor resistance control b) Cascade control