EDDY-CURRENT LOSSES OF SURFACE-MOUNTED PERMANENT-MAGNET MOTORS

The paper presents an analytical method for estimating the eddy-curren t losses of surface-mounted permanent-magnet motors under load conditi ons. These losses are related to a fictious voltage induced in a one-t urn coil wound around a stator tooth. A simple way to calculate part o f the load currents for this voltage is described. It is shown that on ly the windings found in adjacent slots to the stator tooth considered contribute to it. Waveforms of this fictious voltage, including the l oad current effects, are shown. They illustrate the increase of eddy-c urrent losses with motor load, particularly in conditions of advanced commutation.