With the advent of the EV society, it is important to improve the efficiency of motors and then to evaluate losses. In particular, motor iron loss is difficult to measure, so research into numerical analysis is expected. Iron loss must be calculated taking into account of hysteresis loss, classical eddy current loss, and excess loss, and it is necessary to model it for each frequency range. In addition to the fundamental wave component that generates torque, harmonic components are superimposed on motors, which lead to an increase in eddy current loss. In addition, stress is applied during the manufacturing of the motor core, which leads to changes in the magnetic properties. By modeling them, it is realized to accurately express the actual phenomenon.