Abstract
The physical origin of losses in conducting ferromagnetic materials is the production of heat by the flow of eddy currents in the material. The eddy currents are generated by the voltages caused by changes in the magnetic induction. This statement, although true, is not very helpful in calculating or predicting the actual magnitude of the losses. For such a calculation, we need a detailed knowledge of the mechanism of magnetization reversal. The present standing of efforts to predict losses is briefly reviewed and discussed.