Fans all need to frequently adjust the flow rate according to the load of the main unit. Currently, the energy-saving adjustment methods for fans in stone processing enterprises are rather outdated, and throttling regulation is generally adopted. When throttling regulation is employed, the flow rate of the fan is mainly adjusted by regulating valves or throttling baffles. The throttling amount of the fan is large, and it may even be throttled by more than 50% under low load conditions. Due to the existence of throttling losses and operation deviating from the high-efficiency zone, the waste of energy is extremely serious. However, if the rotational speed of the fan is adjusted, not only can the throttling losses be eliminated, but also the fan can be ensured to always operate in the high-efficiency zone. Therefore, a significant amount of electrical energy can be saved. It can be said that adjusting the rotational speed of the fan to operate it is an effective energy-saving method, which reflects the new trend in the current production of building materials industry.