Temperature dependence of loss separation measurements for oriented silicon steels

Loss separation measurements were made over the temperature range of 20 to 200°C for 0.22-mm and 0.29-mm thick regular grain oriented (RGO) and 0.31-mm thick high permeability oriented (HGO) Epstein samples. The 0.22-mm thick RGO sample had only a forsterite coating, while the thicker samples had secondary high stress coatings. Over the temperature range of 20 to 100°C the change in hysteresis loss Phwith temperature was negligible for all samples. Since the total core loss PTdecreased with increasing temperature over this range, almost all the loss reduction was due to a reduction in the eddy current loss component Pewhich was inversely proportional to the resistivity. The eddy current loss anomaly factors η exhibited little variability with increasing temperature, indicating that domain wall spacings did not change with increasing temperature.