In addition to "220V Cooling Fan" stationary noise itself, there are many sources of noise, such as: bearings due to lack of precision, improper assembly or poor maintenance can cause abnormal noise in addition to the fixed noise fan itself, there are many noise sources. such as: bearings due to lack of precision, improper assembly or poor maintenance can cause abnormal noise of the motor part will produce noise some poor design or manufacture of controlled goods caused by the poor, but sometimes inside and outside the motor of "220V Cooling Fan" cause. ??? Most motors will produce noise, some are poor design or manufacture of controlled goods caused by the poor, but sometimes inside and outside the motor of "220V Cooling Fan" cause gear and belt will also cause noise due to friction gear and belt will cause friction noise. Noise resonance of other structures arising should not be ignored, which is sometimes due to the imbalance caused by the body.