Slip Ring Induction Motor Rotor Connection

It consists laminated cylindrical core which has a semi closed slot at the outer periphery and carries three phase insulated winding.

Slip ring induction motor rotor connection.

However the rotor construction of the slip ring motor is quite interesting. Slip ring induction motor is one of the types of 3 phase induction motor and is a wound rotor motor type. The three terminals of star connected rotor windings are brought out and are connected to the external resistors through the slip ring. The rotor is wound for the same number of poles as that of the stator.

The working principles and stator construction of the slip ring induction motor are exactly the same as that of the squirrel cage motor. Because of various advantages like low initial current high starting torque and improved power factor it is used in applications that require high torque cranes and elevators. Adjusting the resistance allows control of the speed torque characteristic of the motor. The major difference between squirrel cage rotor and wound type rotor is the presence of a slip ring in wound type rotor hence it is also called a slip ring rotor.

The motor which employing the wound rotor is known as a slip ring induction motor or phase wound motor.