Classification of diagnostic indexes for field oriented induction motor drives

Noninvasive diagnosis of incipient faults of mains supplied electric machine is a wide spread technology, that allows cost-savings. Inverter-fed machines are becoming commonly available, thanks to technology advances. The traditional MCSA fails for closed loop machines, because of regulators impact on electrical quantities. The paper includes a study on the stator faults impact on controlled variables and machine input variables in function of drive operating frequency. This study is aimed at the development of new diagnostics indexes fitted to closed loop machines faults.