Squirrel Cage Motors
The rotor of a squirrel cage motor is made of conductive bars that are parallel to the shaft and short circuited by the end rings in which they are physically supported .Wound Rotor Induction Motor
The wound rotor induction motor operates on the same principles as the squirrel cage motor, but differs in the construction of the rotor. Instead of shorted bars, the rotor is made up of windings which terminate at slip rings on the shaft.
This type of motor is used in special applications where a high starting torque is required. Connection of external resistance to the rotor circuit via the slip rings permits variation of motor torque-speed characteristics . After starting, the slip rings are shorted together.
Shorting the external connection results in operation similar to squirrel cage motors.
