A Multifunction Energy Saving Device with a novel power-off control strategy for beam pumping motors

Based on the analysis of the measured load curves of more than 300 beam pumping motors in China, a novel power-off control strategy is proposed in this paper, which makes full use of down-stroke potential energy and includes two novel control technologies, namely, automatic tracking load variation and rapid soft re-switching of power source. Meanwhile, considering the complicated load condition, a Multifunctional Energy Saving Device (MESD) is developed. It not only contains the novel power-off control strategy but also integrates the improved wye-delta automatic conversion and auto-reactive power compensation, so that it can be used for any beam pumping unit. Furthermore, the application of the MESD in Daqing oil field is also introduced. In the past four years, the energy saving rate of more than 535 trial Devices is in the range of 10-25%.