PREDICTION OF MECHANICAL-STRESS EFFECTS ON THE IRON LOSS IN ELECTRICAL MACHINES

Iron losses can account for a significant portion of the total loss in electrical machines. Nevertheless, although analytical and numerical techniques have been developed for predicting the iron loss density di stribution and the total iron loss of various types of machine under a ny operating load condition, to date these have neglected the effect o f mechanical stress. However; during the manufacture of many electrica l machines, a significant radial compressive stress can be imposed on the stator lamination stack, by shrink fitting/pressing an outer frame , for example. This paper describes a technique that has been develope d for predicting the effect of compressive stress on the iron loss den sity in lamination materials, and demonstrates its use in calculating the iron loss of a permanent magnet brushless de motor. (C) 1997 Ameri can Institute of Physics.