EDDY-CURRENT LOSSES AND NUMBER OF DOMAIN-WALLS WITH RESPECT TO TOTAL NUMBER OF LAYERS FOR VERY THIN 3-PERCENT SI-FE STRIP-WOUND CORES

The relation between the domain wall motion and the eddy current losse s of very thin (110)[001] 3% Si-Fe strip-wound cores were investigated . The measured eddy current losses were larger than those estimated us ing a modified Pry and Bean model in the frequency region 50-500 Hz. I t is known that the domain walls of thick (110)[001] 3% Si-Fe strips m ove nonuniformly in the low-frequency range (0.1-100 Hz), but this fre quency range is lower than that usually used for very thin strips. By measuring the flux voltage in every layer, we found that the voltage w aveforms were not sinusoidal, even if the secondary voltage waveform o f the core was sinusoidal, and the magnitude of the voltage in each la yer was not uniform. These results indicate that the domain wall motio n of very thin strips is not uniform, even at 50-500 Hz. The nonunifor mity of the domain wall motion makes the eddy current losses larger th an those estimated by means of the modified Pry and Bean model.