The induction motor is similar to the transformer with the exception that its secondary windings are free to rotate.
Where ER is the induced voltage in the rotor and RR is the rotor resistance.
Now we can calculate the rotor current as,
Where ER0 is the induced voltage and XR0 is the rotor reactance at blocked rotor condition (s = 1).
Now as we managed to solve the induced voltage and different frequency problems, we can combine the stator and rotor circuits in one equivalent circuit