ADD:No.789,liming South Road,RongCheng City,Shandong Province,China.
The cause of ventilation noise
The ventilation noise of the motor mainly consists of the following three components
(1) eddy fan blades produce eddy currents around the gas when they rotate. The eddy is decomposed into a series of small eddy currents due to the viscous force, which makes the air disturbed, resulting in noise. In addition, at the turn of the air flow, if there is a larger cavity, the sound of the eddy will be produced. Eddy current is a kind of random steady noise of wide band.
(2) monotonic sound (Qi Disheng) is a single frequency noise generated by fan rotation, which makes cooling gas periodically pulsate and air impingement heat dissipation bars, fastening bolts and other outburst obstacles.
(3) the resonance noise caused by the resonance of the thin-walled parts in the wind road, such as the wind hood.
The ventilation system of the motor is quite complex, and they can adopt different wind structure, such as axial ventilation, radial ventilation and mixed ventilation. Different fans can be used, such as centrifugal fan, axial flow fan and so on. As far as the same wind structure and fan are concerned, the layout and structure of the ventilation element can be different. Therefore, it is impossible to solve the calculation problem of ventilation and noise of all motors by one way, and the influence of many factors can only be analyzed by a lot of experiments.