Measurement and Its Evaluations of Cogging Torque for Lundell Alternator

Abstract

It is extremely difficult to investigate cogging torque of a rotating electric machine precisely. Two dimensional finite element based analytical approaches have been developed and implemented for the magnetic force in general salient-pole motors. However, for Lundell alternators which are widely used for factory automation, automobiles and so on, it is necessary to use three dimensional analysis. In this paper, a new and precise cogging torque measurement method and the data processing technique are proposed for Lundell alternator. By using this method, practical test data for a Lundell alternator are presented and the characteristics of cogging torque are clarified and evaluated.