Influence of material and thickness of slot insulation of the electric machine on the bearing voltage ratio

Abstract

The Modern electrical drive systems which able to operate in variable-speed mode became a conventional setup since power electronics-based frequency converters became wide spread. Nevertheless, specific parasitic phenomena of bearing currents always accompanying drive systems fed by frequency converters. In electrical machines, especially in small size motors, major role in parasitic current patch plays capacitance between stator winding and rotor surface. In this paper it will be considered influence of winding insulation type on the bearing voltage ratio and corresponding winding-to-rotor capacitance.