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