Reduction of Iron Losses in Actual Motors by Secondary Current Heating Method

Abstract

In this paper, the “Secondary Current Heating method,” which has been proposed in the previous reports, was used to heat-treat the laminated stator cores of actual motors to reduce iron loss. To evaluate the magnetic properties of the laminated stator cores including the teeth, an inner core was installed inside the stator to form a closed magnetic path with the two teeth, back yoke, and inner core. The air gap between the stator and the inner core causes the loops to be tilted compared to the B-H loop of the back yoke, though, it was found that the iron losses were reduced by about 30% in the laminated stator core after heat treatment.