In most factories, the ventilation equipment used is mostly large-volume belt-driven centrifugal fans. Although the mechanical structure of centrifugal fans is usually not worn out, as the main transmission component, the belt is used for a long time. It needs to be replaced, especially the belt that has cracked and cannot maintain its tightness after adjustment, and needs to be replaced in time.
Centrifugal fan belt replacement method
1. Removal of old belts
First, use a suitable wrench to loosen the positioning bolts on the motor base, and then loosen the fixing device of the adjusting top wire on the motor near the centrifugal fan to minimize the distance between the fan pulley and the motor pulley.
(1) For the centrifugal fan motor with two belts, when removing the outer belt, you can place the inner side of the three fingers of one hand under the belt, and then apply force outward, and turn the belt clockwise to remove, and the inner belt can be removed. The method is the same.
(2) For centrifugal fan motors with three or more belts, the removal method of the inner and outer belts is the same as above, and the middle belts are moved to the outer side according to the groove spacing, and then use the fingers to rotate outwards to remove them, but you need to pay attention to each movement. Always remove your fingers from a safe area in time.
2. New belt installation work
When installing a new belt, you should first put all the belts on the corresponding larger pulleys one by one, and turn the bottom of the belt with your fingers to make it fit the pulley, and then put it on the smaller pulley to make it fit. After the belts are all installed, adjust the top screw by loosening the adjusting positioning bolts on one side of the centrifugal fan motor to gradually increase the distance between the pulleys. 10~20mm, and the tightness of each belt is the same.
After the belt is installed and the tightness is adjusted to normal, it is necessary to adjust the pulley to the same plane with a small wire to ensure that there is no gap between the two adjusted pulleys and the small wire. Then use a wrench to tighten the positioning bolt of the motor, tighten the motor adjusting bolt and top wire, and manually rotate the pulley without abnormal noise, and then carry out the trial operation of the new belt of the centrifugal fan.
3. New belt test run work
After the centrifugal fan is turned on, it is necessary to gradually increase the motor frequency and observe whether the replaced belt has abnormal beating, etc. If there is any abnormality, it is necessary to turn off the power, loosen the bolts and adjust the top wire to adjust the belt. If there is no abnormality, continue to run the centrifugal fan, and carry out patrol inspection in 8 hours and 24 hours, and there is still no abnormality, indicating that the belt replacement of the centrifugal fan is completed.
Centrifugal fan belt replacement precautions
1. Before replacing the belt of the centrifugal fan, the brake should be turned off and a warning sign should be hung up, and the operation should be carried out after the fan stops stably.
2. Two people are required to replace the belt, and keep a certain light intensity on site (usually with running lights, strong light flashlights, etc.).
3. Before replacing the belt, prepare the tools for changing the belt, including a number of beautifying wrenches or open-end wrenches, and a number of small wires.
4. In the process of removing the centrifugal fan belt, it is strictly forbidden for two people to operate at the same time. One person should operate and one person should monitor on site.
5. After the belt is replaced and the centrifugal fan is closed and powered on, all debris on the site must be cleaned up.
