Causes of Vibration in Centrifugal Fans8.0

Causes of Vibration in Centrifugal Fans8.0

There are many causes of vibration in rotating machinery; let us examine the causes of vibration in centrifugal fans. Bearings Bearings must be inspected regularly to prevent failure, as damage to the rotating elements or inner ring of the bearing can damage the bearing flanges on the shaft and cause the unit to vibrate. When inspecting bearings, there are several parameters that must be checked to determine the bearing’s operating condition, as described below. Bearing Housing Foundation Bolts Bearing Temperature Quality of Bearing Lubrication Determination of Bearing Clearance Any Abnormal Noises from the Bearings Bearing Inner Ring, Rotating Elements and Cage Clearance between the Bearing Inner Ring and the Shaft Dimensions to Which the Bearing Is Fixed Bearings must be lubricated regularly to ensure their effective operation. Concrete foundation The concrete foundation must not crack and must be level to prevent vibration. If any cracks are observed, this will affect the bearings and, consequently, the foundation fastenings. To prevent concrete cracking, we must maintain other parameters within effective operating limits so that no vibration occurs, as concrete cracks due to vibration. If misalignment occurs, the shaft will deflect due to the centrifugal fan unit operating continuously in a misaligned state. Even if a modified shaft is used, we must still replace the shaft, as it cannot be fully rectified. The new shaft must possess certain key characteristics to prevent shaft bending issues. The shaft material must be EN 24 to provide the required hardness of approximately 50 to 60 HRC. The shaft must have a stress concentration factor; sharp steps must be avoided, and we will have to use steps with a radius of 3 mm instead of sharp steps. Pulsation when the inlet vane is closed To avoid impact, the inlet valve must be closed or opened slowly; this can be carried out by the operating team following operational training. Gearbox As discussed, the gearbox consists of gears, shafts, bearings, oil and seals. We must check the oil level daily; if the gearbox oil level is low, it will overheat due to excessive friction between the meshing gears. If the gearbox oil level is too high, the gear oil temperature will also be high, which may damage the seals; once the seals are damaged, oil will leak from the gearbox. Therefore, we must inspect the gearbox daily, checking the following parameters to permanently resolve the issue of bolts frequently coming loose. Routine inspection of fasteners to avoid vibration problems.