Many modern induction motor applications involve nonsinusoidal voltage supply. Under such operating conditions the motor performance can be seriously affected while the standard equivalent circuit is no more adequate for the motor analysis. In this paper, a modified equivalent circuit topology is introduced, in order to account for the increased iron losses associated with the leakage flux and saturation in the motor, in presence of low order harmonies in the supply waveform. This equivalent circuit allows the prediction of the motor performance under nonsinusoidal operation. The proposed results have been checked by means of an experimental setup, comprising an inverter-fed 1.5 kW induction motor.