Diagnosis of rolling bearings faults in electric machines through stray magnetic flux monitoring

The most frequent causes of failure in electrical machines are due to bearing related faults. By means of advanced diagnosis methods, it is possible to detect these faults in their incipient phase, before the catastrophic effects of the failures can occur. In this paper, a new bearing fault diagnosis method by means of statistical analysis of the stator current and of the stray flux around an induction motor is presented. The experimental tests were carried out on a three-phase induction motor with three different bearing faults: crack in the outer race, hole in the outer race and deformation of the protective seal.