At the initial stage of centrifugal fan impeller operation and during all regular inspections, as long as there is an opportunity, the impeller must be inspected for cracks, wear, dust and other defects. As long as possible, it is necessary to keep the impeller clean, and regularly use a wire brush to remove the dust and rust on it, because as the running time increases, it is impossible for these dust to evenly adhere to the impeller of the centrifugal fan. And cause the impeller balance of the centrifugal fan to be damaged, so as to cause the rotor to vibrate. As long as the centrifugal fan impeller is repaired, it needs to be dynamically balanced again. If possible, a portable test dynamic balancer can be used to balance on site. Before performing dynamic balancing, it is necessary to check whether all set bolts are tight. Because the centrifugal fan impeller has been running unbalanced for some time, these bolts may have come loose.