Impact of Shearing Stress on Magnetic Properties of Different Size Motor Iron Cores

The deterioration level of the magnetic properties of motor iron core due to its size reduction after punching was quantified. The internal causes for the magnetic property deterioration, including the changes of shearing surface and internal texture, were researched. The results show that during the manufacture of the iron cores, stress relief annealing should be done when the width of core tooth is less than 15 mm.