With the continuous development of the motor industry, the extension and connotation of motor products are also expanding. Motor products are widely used in metallurgy, electric power, petrochemical, coal, mining, building materials, papermaking, municipal administration, water conservancy, shipbuilding, port handling and other fields. The versatility of the motor gradually develops in the direction of specificity, breaking the situation that the same motor was used for different load types and different occasions in the past. The small motor manufacturing industry is developing in the direction of scale, standardization and automation, while the large and medium-sized motor manufacturing industry is developing in the direction of increasing single machine capacity, specialization, diversification and customization. At the same time, energy saving is also the development trend of the whole industry.