Eddy current losses of segmented Nd‐Fe‐B sintered magnets without insulation under various conditions

The purpose of this paper is to examine the mechanism of the increase or decrease of eddy current loss of the segmented Nd‐Fe‐B sintered magnets without insulation, and the effects of parameters on such a phenomenon are discussed.

The measured contact resistance is used in the finite element analysis.

It is shown that the eddy current loss in a magnet shows the peak value when the number of segments are increased at 40 kHz, but this property is changed at low frequency (10 kHz). Its tendency is changed by the contact resistance and the permeance (surrounding iron core).

The reason of a curious property of eddy current loss of segmented magnets is clearly explained by examining the eddy current distribution at various contact resistances.