When will rotor resistance dominate rotor reactance and vice-versa?

(i) When a 3-phase induction motor is in normal operation, the rotor frequency f ‘= s f where f is the supply frequency) is low and so is the rotor reactance. The current that flows is then largely limited by rotor resistance rather than reactance.

(ii) When the rotor is stationary (i.e. at standstill), s = 1. This means that rotor sees the full‑line frequency (i.e. f’ = f) and its reactance is dominant compared to its resistance.