Many companies that started developing wind turbines recently began to realize that the advantages of high-performance ceramic ball hybrid bearings, especially when using ceramic ball bearing, can increase the rotational speed of 30rpm of the rotor shaft of the wind turbine to 2000rpm, so as to generate more electric energy. Silicon nitride ball is an ideal product to improve the performance of bearing. Compared with steel ball, silicon nitride ball is lighter, more rigid, harder, smoother and corrosion resistant. It doesn't need much lubrication and has lower thermal expansion coefficient. These properties make the bearings work faster, work at higher temperatures, and reduce lubrication and maintenance. Silicon nitride balls are extremely wear-resistant. The longer life of bearings means that the cycle of bearing replacement is greatly prolonged and the replacement cost is greatly reduced. Because the lifting equipment is needed to replace bearings, the cost of replacement is generally estimated at RMB 70 thousand yuan. This effect is particularly evident in the rotating shaft system of the high speed generator.