How a 3 phase motor works?

(Image: Stator)

   
















(Image: Rotor)

Three phase induction motors are classified into two types  based on their rotor construction. i) squirrel cage motor ii) slip ring induction motor. here we will see how squirrel cage induction motor works? The figures of stator and rotor shown.

The stator has windings around it that are placed 120° apart. The rotor is a form-wound type or cage type. The squirrel cage rotor is standard for motors smaller than 1 horsepower, which we are concerned with here.The rotor windings are wrapped and tied together.so it looks like a squirrel cage.

(Image:3Phase Motor Animation)

when we pass a three phase supply to stator windings, it will produce three phase alternating flux which is rotating in nature. In this motor stator acts like a primary winding of transformer. No supply is given to rotor.But it will produce a flux. How means the rotating flux produced by stator will cut by rotor conductors.  This induces voltage and causes the rotor current to flow. So, motor torque is developed by the interaction of the rotor current and the magnetic revolving field.hence it is called squirrel cage induction motor