This construction of the rotor is aimed at reducing the phase difference.
Slip ring induction motor rotor connection.
A wound rotor motor also known as slip ring rotor motor is a type of induction motor where the rotor windings are connected through slip rings to external resistance.
Adjusting the resistance allows control of the speed torque characteristic of the motor.
The working principles and stator construction of the slip ring induction motor are exactly the same as that of the squirrel cage motor.
The three terminals of star connected rotor windings are brought out and are connected to the external resistors through the slip ring.
Slip ring induction motor is one of the types of 3 phase induction motor and is a wound rotor motor type.
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.
Instead of bars in this motor three windings are used.
It consists laminated cylindrical core which has a semi closed slot at the outer periphery and carries three phase insulated winding.
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.