Since the motor core is often affected by various physical factors such as magnetic field, temperature field, stress field, and frequency during the working process; at the same time, different processing factors such as residual stress generated by stamping and shearing of silicon steel sheets, the distance between the shell and the stator core The compressive stress generated by the heat sleeve, the centrifugal tension generated by the high-speed operation of the rotor, and the gradient temperature generated by the temperature rise characteristics will all affect the overall performance of the core. These factors will cause the iron loss of the motor core to be higher than the normal value and cause non-negligible deterioration.
The research results at home and abroad show that: the iron core of the motor usually works at high temperature, the iron loss of ordinary silicon steel sheet decreases with the increase of temperature, while the iron loss of 6.5% high silicon steel increases with the increase of temperature. For motors installed with an interference fit in the case, the case will exert great stress on the iron core, and the motor iron core will bear a compressive stress of about 10Mpa-150Mpa during operation, and the block type iron core is more conducive to mass production, which is often A shrink fit or compression process is required to fix the core, and the iron loss of the motor with shrink fit or press fit increases significantly compared to the unstressed case. The silicon content of 6.5% high silicon steel is much higher than that of traditional silicon steel, so the iron loss of 6.5% high silicon steel is lower due to the increase of compressive stress, while the iron loss of traditional silicon steel is higher due to the increase of compressive stress. The deterioration of iron loss by compressive stress is limited, and when the stress reaches a certain value, the deterioration of iron loss is no longer obvious.
Ma Deji, a researcher at Shenyang University of Technology, tested the magnetic properties of 6.5% high-silicon steel under the conditions of compressive stress and temperature coupling, and revised the iron loss model, and compared 6.5 % high-silicon steel with traditional silicon steel. From the perspective of materials, the advantages of 6.5% high silicon steel are analyzed . And feed back to the motor core to make its performance more excellent.
Through the research on the iron loss performance of 6.5% Si under variable temperature and stress, the researchers found that: when the temperature and the compressive stress acting on the material increase, compared with other traditional silicon steels, the loss deterioration of 6.5 % Si is very small; 6.5% high-silicon steel has less iron loss deterioration under multi-physics coupling conditions because of internal stress, small hysteresis coefficient and large grain size; when 6.5% high-silicon steel is used to make the motor stator core, the casing adopts shrink fit Installed in the same way, there will be a small iron loss loss.
Post time: Apr-15-2023