Misalignment fault analysis and diagnosis in switched reluctance motor

The magnetic characteristics of a Switched Reluctance Motor (SRM) in normal and abnormal conditions are important in performance prediction and verification of the motor. In this paper, a novel view of air gap magnetic field analysis of SRM under rotor misalignment is presented. This analysis is based on a three-dimensional finite element method (FEM) to provide the precise fault diagnosis. This method is used to simulate reliable and precise model by considering the end effects as well as axial fringing effects. The FE analysis are performed to obtain the static magnetic characteristics of SRM including flux linkages, terminal inductance and static torque profile under different rotor positions for varying degree of misalignments. To do so, Fourier analysis is carried out to study the variations of diagnosis index. Inductance waveforms were analyzed by FFT, and the concept of relative spectral coefficient from the FFT analysis is given as a fault diagnosis index, and its sensitivity to SRM misalignment fault is shown under different conditions. The obtained results present useful information with regard to the detection as well as the amount of misalignment fault. To the best knowledge of the authors, such an analysis has not been carried out previously.