Wavelet analysis of torque at startup of an induction machine under inter-turn short-circuit

The paper deals with a field-circuit transient analysis of a squirrel cage induction motor taking into account a inter-turn short circuit. Numerical simulations were carried out for a selected number of shorted turns. The elaborated model consists of field, circuit and motion equations. Based on the models, torque waveforms have been charted. Torque waveforms have been designated for two states of the machine - one with a rated load and the other with no-load. Special attention was paid to analysis of torque during the startup state. Due to the non-stationary of the torque waveform, the wavelet analysis was used.