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|Dear Members, I hope you can help me with my fan problem. I recently stripped, cleaned and lubricated my fan; the bearings are of the 'bush' type. Without the fan blades attached, the motor runs silent and smooth. However, as soon as the fan blades are attached and the motor switched on: a rhythmical knocking noise is audible and gets louder with the gradual increased speed of the fan blades at start up and gets louder still, at maximum speed. When the fan is switch off the knocking sound immediately stops, even though the fan blades are still spinning for an extended period of time, as the fan is well lubricated. The rotor shaft has no flat surface for the fan blade fixing screw to bed down on, but there is no play. The fan blade angles/attitude are relatively the same, so I would assume, although not perfect, the fan blades are relatively balanced.
The mechanical load of the fan blades on the motor seems to be causing the knocking sound but what is actually making the knocking sound is a mystery to me. Thank you in advance for any suggestions you may have. The model of my fan is the same as the model in the video I discovered on you tube; Link below.
Last edited on Wed Jan 19th, 2022 07:06 pm by Michael Gyles