The importance of partial discharge testing in electric motors

BY VICKI WARREN, Iris Power LLP

Comparing partial discharge (PD) results obtained from a single machine is a valuable tool that enables companies to observe the gradual deterioration of a machine stator winding. Proper monitoring of stator winding deterioration allows companies to plan appropriate maintenance for the machine in accordance to International Electrotechnical Commission’s IEC 60034 standard: “Rotating Electrical Machines - Part 27-2: Online Partial Discharge Measurements on the Stator Winding Insulation of Rotating Electrical Machines”, also known as IEC/TS 60034-27-2.

However, a few recent case studies have shown that modern air-cooled stator windings are suffering from premature deterioration of the insulation.