Examination of Temperature Characteristics of Magnetic Properties Using a Single Sheet Tester

If the magnetic field in a magnetic device which is operated at high temperature, for example 100 °C, is analyzed using magnetic characteristics at a room temperature (RT), there occur some errors. Although the measurement method using a single sheet tester (SST) has advantages that the material characteristics can be measured precisely, the research about the correlation between the temperature and the magnetic characteristics using SST is few. In this paper, firstly, the temperature characteristics of magnetic properties of silicon steel sheet were measured using SST, then, the temperature characteristics of the iron loss of the permanent magnet motor were estimated by using the finite element method (FEM). It is shown that the permeability is increased at low flux density, and decreased at high flux density when the temperature is increased. The iron loss is decreased similarly in almost all range of B_m. The change of iron loss is remarkable in the low grade steel (50A1300). The iron loss of SPM motor at 100 °C is decreased by about 10–20% compared with that at RT.