Aging Tests on Nanostructured Enamels for Winding Wire Insulation

Early failures due to stator insulation breakdown are still frequently experienced in industrial applications where low-voltage induction motors are fed by adjustable speed drives. Such events are caused by the quick erosion of organic insulating materials used in Type I random wire wound windings when the inception of partial discharges (PDs) is triggered by the severe electrical stress produced by fast switching electronic converters. The present experimental work provides some interesting results about the medium-long-term behavior of nanostructured organic-inorganic enamel-based compounds in the presence of PDs. The outcome evidences that polymeric-nanocomposite enamels may provide a strong enhancement of the duration; thus, they could be proficiently adopted as the stator winding primary insulation.