Study of High Efficiency and High Starting Torque Permanent Magnet Synchronous Motors Used in Pump Jacks

Now the motors used in pump jacks are usually three-phase induction motors. To meet the requirement for high starting torque, large capacity motors are used. However, since the normal output is only 20-30% of rated power, the efficiency and power factor are low. To overcome this problem, permanent magnet synchronous motor (PMSM) of high efficiency and high starting torque is developed in this paper to replace induction motor used in pump jacks. Measures to improve the efficiency, starting torque and to broaden economic operation range for PMSMs are studied, and the corresponding design guideline is proposed. The effects of ambient temperature on performances of PMSM are studied to ensure the performance of PMSM. Being based on the above, PMSM series products used in pump jack are developed. Experimental results show that the PMSMs developed in this paper can replace induction motors that are two power grades higher than it.