12. What are the causes of vibration in the main fan unit?

Reasons for vibration in fans: 1. Vibration caused by an excessive clearance between the impeller and the main shaft. The main reason for this is errors in the precision of machining during the production of the impeller; the shaft head becomes elliptical, which reduces the contact area between the two components, changing from surface contact to point contact. Also, during the repair process, maintenance personnel used fine sandpaper to grind the shaft ends; after multiple repairs, this resulted in an excessive clearance between the main shaft end and the impeller.   2. Vibration caused by the imbalance of the impeller itself, which can result from loose, altered, deformed components on the impeller, or from uneven corrosion and wear ； Solid particles in the working medium deposit on the rotor ； The weight of the new parts replaced during maintenance is uneven ； The material of the impeller during manufacturing is not absolutely uniform ； There are errors in machining precision and deviations in assembly, etc. The impeller itself is unbalanced, and impeller imbalance can be divided into dynamic imbalance (couple imbalance) and static imbalance (torque imbalance). 3. The main shaft bends, and the primary reason for this is that the fan remains unused for long periods of time; under the weight of its own components, the impeller on the main shaft bends and deforms. This situation often occurs when a fan that was operating normally is shut down and then restarted, resulting in excessive vibration of the fan. Furthermore, in spindle unit 3, the spindle bends. The main reason for this is that the fan has been out of use for a long time, causing the spindle impeller to bend and deform under its own weight. This situation often occurs when a fan that was operating normally is shut down and restarted, resulting in excessive vibration of the fan.

1: The concentricity of the unit changes. 2: The dynamic balance of the rotor is disrupted. 3: The bearings are damaged or the lubricating oil has deteriorated. 4: Operating at low flow rates.