Study on the performance sensitivity to ambient temperature for permanent magnet synchronous motor used in pump jack

Since permanent magnet synchronous motors (PMSM) have the advantages of high efficiency and high power factor in comparison with induction motors, much energy would be saved if PMSMs are adopted in pump jacks in oil fields. However, the pump jacks work in the open air, and the ambient temperature changes greatly, which has great effects on the performances of PMSM. In this paper, the effects of ambient temperature on the performances of PMSM are studied. The study shows that the ambient temperature has great effects on the starting and no-load performances. When ambient temperature is high, irreversible demagnetization may occur. When ambient temperature is too low, the PMSM maybe cannot start with rated load because of the minimum torque.