The loss calculation in soft magnetic materials, used in the manufacturing
industry, is still ruled by Steinmetz's simple law. It has remained
unchallenged for more than a century, unproven but successfully used by
designers of magnetic components. Based on experiments carried out on soft
NO Fe–Si and Mn–Zn ferrite samples, in this paper we present a model of
Steinmetz's approximation, based on the hyperbolic model. We also make
suggestions for the formula's possible extension to a wider range of
coercivity, possibly covering not only soft iron but also other groups of
magnetic materials as well, used in industry.