Relationship Between Temperature Control and Iron Loss Reduction by Secondary Current Heating Method

In this article, we investigated the relationship between temperature controls by heat treatment conditions and iron loss reduction rates in order to further reduce the total iron loss of laminated stator cores using our proposed secondary current heating method. Unlike conventional heat treatment, the secondary current heating method can directly heat the heated material itself. In order to further reduce the total iron loss, several temperature controls were performed by adjusting the primary excitation coil voltage of the secondary current heating system, and the proper heat treatment conditions were investigated from the viewpoint of reducing hysteresis losses and eddy current losses among the total iron losses. As a result, it was found that temperature holding at around the recommended annealing temperature ( $720~^{\circ }$ C– $750~^{\circ }$ C) was effective in reducing hysteresis losses and that the total iron losses could be reduced by 58%.