The effect of inverter characteristics on partial discharge and life behavior of wire insulation

It has been demonstrated already that adjustable speed drives, and, in general, power electronics waveforms, can harm insulation systems of rotating machines, causing significant reduction of reliability and life. Indeed, the type of supply voltage made by repetitive impulses alters significantly the electric field distribution in the turn-to-turn and phase-to-ground insulation, and also the machine terminal peak voltage can be increased significantly, with respect to the expected value at the inverter output [1]-[11].