Magnetic Power Loss Characteristics of Non-oriented Electrical Steel Sheets under Stress

The stress that acts on the core by installing a stator in a frame influences the performance of a motor. To reflect this influence in the equipment design, the stress dependence of the magnetic property was examined for non-oriented electrical steels, which are the core materials. This time, the stress dependence of the magnetic power loss in the range of ±225 MPa was evaluated for high-grade non-oriented electrical steel sheets of 0.5 mm thickness, and the following results were obtained. (1) The influence on the magnetic power loss is larger under compression than under tensile stress. The loss increases rapidly with an increase in the compressive stress. However, when the stress exceeds -50 MPa, the saturation tendency of the loss gradually becomes strong. (2) The influence of the stress on the magnetic power loss is different in the rolling direction and the traverse direction. (3) A greater magnetic power loss that occurs with compressive stress is mainly due to an increase in hysteresis loss, and the eddy current loss also increases slightly. It is thought that this slight increase in the eddy current loss that occurs with compressive stress depends on the change in the anomalous loss.