Non-invasive early detection methods of shorted turns in converter-fed induction motor, part I

This paper deals with the problem of the early stator faults (the short-circuits) detection and localization of the induction motors supplied from the frequency converter. A stator fault detection method based on monitoring of RMS stator current value, the phase shift between the line currents, the spectral analysis of the line current and negative current symmetrical component analysis are presented. Tests were realized for different load torque and supply frequencies, what enabled the evaluating of the usefulness of the proposed analysis in the diagnostics of the stator faults in the converter-fed induction motor drives