Monitoring of the asynchronous machine faults using the signal approach

The faults monitoring of the asynchronous machine using the stator current is of great interest, since this latter is an accessible and a measurable quantity. The spectral analysis of the stator current makes it possible to highlight the characteristic frequencies of the faults but in a broad frequency band depend on half of the sampling rate, which makes the online monitoring of the faults very difficult. In order to facilitate the exploitation of the relevant frequencies of the broken bar fault, we propose the extraction of the frequency components using the instantaneous frequency method. The theoretical bases of this method are presented and the results are validated on a testing bench comprising an asynchronous machine of 5.5 kw.