Recent developments in the high energy magnets fields determined a widespread interest for the permanent magnet (PM) motors designers. The requirements regarding the high specific energy for the motor are satisfied by the NdFeB magnets, which are the most utilizable, due their easier manufacturing and relative law price. Unfortunately, at the temperature range (above 150oC) of the PM motors operating regimes, it is produced a reversible demagnetization of the Neodymium magnets, which determines negative effects on the torque capability. The paper deals with the temperature effects on the torque production and on the efficiency of the PM motors using Neodymium magnets. The main parameters of the magnets and of the motor which are influenced by the temperature are presented.

Keywords: PM motors, Temperature, Magnets, Torque, Efficiency.