Condition monitoring of mechanical faults in induction machines from electrical signatures: Review of different techniques

Condition monitoring of electric machines is a procedure of increasing importance, as fault tolerant systems are becoming mandatory in many applications. Early diagnosis of faults is a basic pillar in order to achieve full tolerance by the maintenance of faulty parts in electrical machines. As far as electrical drives are concerned, the share of mechanical faults (imbalances, gears and bearings) is very high. The mechanical fault detection is typically based on vibration signals, a robust and effective technique, that is quite invasive and with high latency. Recently, many theoretical and signalbased methods have been investigated for early diagnosis of mechanical faults by electrical machine signals. This paper will review methods for condition monitoring of mechanical faults, with special reference on those based on electrical signals and quite effective also for an early detection: generalized roughness and realistic incipient faults.