Bearing damage detection via wavelet packet

Bearing faults are one of the major causes of motor failures. The bearing defects induce vibration resulting in the modulation of the stator current. In this paper, the stator current is analyzed via wavelet packet decomposition to detect beating defects. The proposed method enables the analysis of frequency bands that can accommodate the rotational speed dependence of the beating-defect frequencies. The wavelet packet decomposition also provides a better treatment of nonstationary stator current than currently used Fourier techniques.