This paper describes a simple method of approximating hysteresis changes in electrical steel sheets. This method is based on assumptions that flux density or field strength changes are a sum or a difference of functions that describe one curve of the limiting hysteresis loop and a certain ‘transient’ component. Appropriate formulas that present the flux density as functions of the field strength and those that present inverse dependencies are proposed. An application of this approximation requires knowledge of the measured limiting hysteresis loop and a few minor loops. Algorithms for determining changes in the flux density or field strength are proposed and discussed. The correctness of the proposed approximation of hysteresis changes was verified through a comparison of measured hysteresis loops with the loops calculated for several different excitations of the magnetic field occurring in dynamo and transformer steel sheets. Additionally, an example of the application of the proposed approximation of hysteresis changes is discussed in the paper. The proposed approximation of hysteresis changes is recommended for numerical calculations of the magnetic field distribution in dynamo and transformer steel sheets.

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The main purpose of the paper is to present a method which allows taking into account the anisotropic properties of dynamo steel sheets. An additional aim is to briefly present anisotropic properties of these sheets which are caused by occurrences of some textures. In order to take into account textures occurring in dynamo sheets, a certain sheet sample is divided into elementary segments. Two matrix equations, describing changes of the magnetic field, are transformed to one non-linear algebraic equation in which the field strength components are unknown. In this transformation the flux densities assigned to individual elementary segments are replaced by functions of flux densities of easy magnetization axes of all textures occurring in the given dynamo sheet. The procedure presented in the paper allows determining one non-linear matrix equation of the magnetic field distribution; in this equation all textures occurring in a dynamo sheet are included. Information about textures occurring in typical dynamo sheets may be used in various approaches regarding the inclusion of anisotropic properties of these sheets, but above all, the presented method can be helpful in calculations of the magnetic field distribution in anisotropic dynamo sheets.

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