说明：  三相异步电动机的用电量占全国总用电量的 60％以上，研究其节能问题，提高其运行效率对节约 能源有重要的现实意义
(Electricity accounts for the country s total electricity consumption of the three-phase asynchronous motor More than 60 , the study of its energy problems, improve its operating efficiency and conservation, Energy has an important practical significance)