IEEE Schenectady Section


The Effect of Voltage Impulses from Variable Speed Drives on Electrical Insulation – June 6, 2019

Voltage source – Pulse Width Modulated inverters can create thousands of short rise time voltage impulses per second. IEEE Schenectady Section would like to invite you to a talk that will focus on the issues associated with these voltage impulses.

TOPIC:  The Effect of Voltage Impulses from Variable Speed Drives on Electrical Insulation

ABSTRACT: Since the introduction of Voltage source – Pulse Width Modulated inverters in variable speed motor drives and doubly-fed induction generators in the early 1990s, the voltage impulses created by the inverters have caused premature winding failure in both low voltage random wound windings as well as high voltage, form wound windings.

The talk will address the origin and characteristics of the voltage impulses, its effect on random wound winding caused by partial discharge, effect on form wound windings via increased PD and/or PD suppression coating overheating. The talk will further address the IEC standards to mitigate the effect of the voltage impulses on random and form wound windings.

PRESENTED BY: Dr. Greg Stone

DATE and TIME: June 6th, 2019, Thursday, 12 to 1:00 PM

LOCATION: Niskayuna Reformed Church Room, 3041 Troy Schenectady Rd, Niskayuna, NY 12309

SPONSORED BY: IEEE Dielectrics and Electrical Insulation Society, IEEE Schenectady Section

LUNCH: Lunch will be provided.


Please contact Supriya Tawde, at by Wednesday, June 5th, 2019 to reserve. This event is free for IEEE members.  There is a $10 fee for non-members.


Dr. Greg Stone was one of the developers of on-line partial discharge test methods to evaluate the condition of the high voltage insulation in stator windings.  From 1975 to 1990 he was a Dielectrics Engineer with Ontario Hydro, a large Canadian power generation company.  Since 1990, Dr. Stone has been employed at Iris Power L.P. in Toronto Canada, a motor and generator condition monitoring company he helped to form.  He has published two books and >200 papers concerned with rotating machine windings. Greg Stone has a PhD in Electrical Engineering, and is a Fellow of the IEEE.