Losses in silicon-iron

Measurements of total power loss and domain-wall spacing have been made on individual grains in polycrystalline specimens of commercial grain-oriented 3% silicon-iron material. The loss-per-cycle against frequency characteristic of a grain is found to consist of discrete linear portions, which correspond to different domain-wall spacings. These changes in domain pattern result in a lower value of static hysteresis loss than expected and, therefore, a larger proportion of the total power loss must be attributed to the anomalous loss. From domain observations, it is concluded that a part of the anomalous loss is due to nonuniform flux distribution in the material and the overloading of the well-oriented grains.