The physical assumptions underlying the static and dynamic Jiles-Atherton (JA) hysteresis models are critically analyzed. It is shown that the energy-balance method used in deriving these models is actually closer to a balance of coenergies, thereby depriving the resulting JA phenomenology of physical meaning. The non-physical basis of its dynamic extension is demonstrated by a sharp contrast between hysteresis loops predicted by the model and those measured for grain-oriented steel under conditions of controlled sinusoidal flux density at frequencies of 50, 100, and 200 Hz.

The article deals with the modelling of dynamic hysteresis loops. The modelling is carried out within the framework proposed by D. Jiles and D. Atherton. The dynamic effect of eddy currents is taken into account using G. Bertotti's approach. A satisfactory agreement between the measured and the modelled dynamic hysteresis loops as well as the corresponding loss densities is obtained.

Even the so‐called non‐oriented steels used in electrical engineering reveal anisotropy of their magnetic properties. Anisotropy may have a substantial impact on the performance of magnetic circuits; therefore it is necessary to take this phenomenon into account already at the design stage. A simple formula useful for the description of magnetisation curves in two principal directions is proposed. The B ( H ) dependencies for other directions are determined using a model based on coenergy concept. The worst magnetic properties are obtained for the samples cut at approximately 60 degrees. The presented description may be useful for prediction of rotational loss in ferromagnetic sheets used as core material in electric machines.