Complex Morlet wavelet amplitude and phase map based bearing fault diagnosis

The continuous wavelet transform enables one to look at the evolution in the time scale joint representation plane. This advantage makes it very suitable for the detection of singularity generated by localized defects in mechanical system. The Fourier spectrum of complex Morlet wavelet is real, which the Fourier spectrum has no complex phase, the complex Morlet wavelet does not affect the phase of a signal in complex domain. This gives a desirable ability to detect the singularity characteristic of a signal precisely. In this study, the complex Morlet wavelet amplitude and phase map are used in conjunction to detect and diagnose the bearing fault. The complex Morlet wavelet amplitude and phase map are found to show distinctive signatures in the presence of bearing inner race or outer race damage. The experimental results show that the Morlet wavelet amplitude and phase map can extract the transients from strong noise signals and can effectively diagnose the faults of bearing.