Reduce rotor voltage

Increase rotor current

Increase the starting torque

Reduce the power loss

To get high running torque

To reduce high starting current

To reduce the load current

To get increased speed at starting

Will not run

Runs at slow speed

Runs at very high speed

Runs but not able to pull load

By cascade operation

By rotor rheostat control

By injecting emf in rotor circuit

By changing the applied frequency

Casecade operation method

By changing the number of stator poles

By injection Emf in rotor circuit

By changing the supplied voltage