This double-disk surface permanent magnet synchronous motor with low speed and high torque, as adopted by the oil-pumping unit, is co-developed by Zhangjiagang City Dahua Machinery Co., Ltd. and Zhejiang University Electrical Engineering Department. It combines the advantages of both permanent magnet motor and disc motor, featuring such noticeable merits as gearbox-free, high accuracy, quick reaction, big acceleration, small oscillation of torque, high overload capacity, low speed with high toque, no interference with power grid, noiselessness, and high energy saving capacity, etc. It is an ideal driving device especially for oil field pumping unit. This motor has been in trial operation for two years. The contrastive test was carried out on two 12-type oil-pumping units loading 10-ton balance weight, one of which was driven by a motor with power at 45 KW, the other was driven by this newly-developed motor. During the 24 hours of test duration, the average power consumption of the two tested oil-pumping units is 15 degree/h and 8 degree/h respectively. We can know from the test result, the oil-pumping units driven by this newly-developed motor can save nearly 50% of power consumption. Oil-pumping unit directly driven by Double-disk surface permanent magnet synchronous motor with low speed and high torque Basic technical parameter Lifting power (excluding balance weight): F>30,000 KN Stroke: S=2-6 m Frequency of stroke: 1-6T/min Voltage of motor-end: U=380V or 660V Working frequency: f=1-8 HZ