Bispectrum and Kurtosis Analysis of Rotor Currents for the Detection of Field Winding Faults in Synchronous Motors

In this work, the application of the bispectrum to rotor current signals is proposed to detect field winding faults in wound rotor synchronous motors. These signals are analyzed both under starting and under steady-state regimes. Furthermore, a new indicator based on bispectral kurtosis is proposed, yielding satisfactory results for fault classification. One of the interesting points of the paper is that a common specific failure pattern is obtained, regardless of the type of motor operating regime. A comparative analysis between the two motor operating regimes is carried out, obtaining several conclusions about the suitability of each regime and, in particular, of the steady-state-based variant for the application of the methodology in real applications.