With the continuous development of motor industry, the extension and connotation of motor products are also expanding. Motor products are widely used in metallurgy, power, petrochemical, coal, mining, building materials, paper making, municipal, water conservancy, shipbuilding, port handling and other fields. The universality of motors is gradually developing towards specificity, which breaks the situation that the same motors were used in different load types and different use occasions in the past. Small motor manufacturing industry is developing towards scale, standardization and automation, while large and medium motor manufacturing industry is developing towards the direction of increasing single machine capacity, requiring specialization, diversification and customization. At the same time, high efficiency and energy saving is also the development trend of the whole industry.