Fans need to adjust the flow frequently according to the host load. At present, the energy-saving adjustment methods of fans in stone processing enterprises are relatively outdated, and throttling is generally adopted. When throttling is used, the flow of the fan is mainly adjusted by adjusting valves or throttling baffles. The throttling flow of the fan is large, even when the load is low, the throttling is more than 50% . Due to the throttling loss and deviation from the high-efficiency zone operation, Energy waste is very serious. And if the fan speed is adjusted, the throttling loss can be eliminated, and the fan can always run in the high-efficiency area, so it can greatly save power. It can be said that adjusting the speed of the fan to run the fan is an effective energy-saving method, which reflects the current new trend of the building materials industry.