Cutting Technologies Influence on Magnetic Properties of Electrical Steels used in High-Efficiency Motors Manufacturing

Aiming to obtain high efficiency electrical machines, the manufacturers pay attention at every aspect, which may lead to the energy loss reduction. The cutting technology is very important, because the classical punching method induces mechanical stresses that affect the total energy losses. In this paper, the magnetic behavior of non-oriented M300-35A electrical steel, cut through punching and water-jet technologies, was investigated. The strips with a width variating between 5 mm and 60 mm and assembled side by side 1, 2, 4, 6, 8, 10 and 12 samples have been prepared. The total energy losses, the magnetic permeability with its components (real and imaginary parts) and the coercive field have been determined as depending on the peak magnetic polarization, with a laboratory Single Strip Tester, at industrial frequency of 50 Hz. The normal magnetization curves were determined by extracting from the experimental measurements the tip points of the nested symmetric minor hysteresis cycles. The study shows that the water-jet cutting technology has a lower impact on the magnetic properties' deterioration.