Analysis And Calculation On Working Performance Of Energy-Saving Motor By Finite Element Method

Beam-pumping units are the main equipments of petroleum extraction in our country, but the power waste of driving motor used in beam-pump unit is large, which lead to low efficiency of oil production system. According to load characteristic of beam-pump unit, the energy-saving motor designed by optimum under controller can change position at suitable moment based on different load of the oil field, the effect of energy saving is remarkable when output characteristic and load match reason is in the best match. Firstly, this paper introduces the design proposal of energy-saving motor, also analyze the operating principle of the energy-saving controller based on inverse-time-lag algorithm and composition and implememtation of Phase-failure Protection Circuit. Secondly, the starting current and starting torque of energy-saving motor measured by experiment and each test parameter in different load is compared with the motor of Y system under the same power point, we can find that the starting current is lower than common motor of Y system but the starting torque is almost equal, and the power factor curve and efficiency curve is better than the common motor of Y system. Thirdly, the solved region, boundary condition and assumption condition of the energy-saving motor are supplied in this paper, the Electromagnetic field theory and the Variation method is applied to found the 2D mathematics model, and the dispersion, element analyze and collectivity composing of time-variation field are given. The calculation result of starting current and starting torque of energy-saving motor and efficiency, power factor, input current and output torque in different constant load by FEM is compared with measured data, which test the calculation result of energy-saving motor by FEM is satisfied with request of engineering. At last, the multi-slice model for the representation of skew is built, which can directly calculate the starting current and starting torque of energy-saving motor according to terminal voltage, the reliability of this method is verified by comparing the values between calculation and test. The energy-saving motor designed by optimum is characterized with small volume, light weight and low material cost,and would be well used on the oil field because it has not only better starting performance but effect of energy-saving in low load.