New aspects of power losses in ferromagnetic cores

Abstract

The total power loss may be divided into three mayor types: the static hysteresis loss, the classical eddy-current loss, and the excess eddy-current loss. In the paper it has been shown that the hysteresis loss must be expressed by different formulae for lower and for upper values of magnetic flux density. On the base of the literature, can be stated that the physical properties of laminated ferromagnetic material – the conductivity and the permeability – are in the external layers of the sheet different than those in the internal layer. The classical eddy-current loss has been calculated taking the effect of sheet heterogeneity into account. The principal cause of the excess eddy-current loss in silicon-iron is the existence of domain structure. This loss has been expressed taking the domain structure and domain wall motion into account.