Commonly used methods for detecting abnormal sounds are close to the ears. The subjective factors are large, it is not easy to identify, and it is easy to cause disputes. If the number of fans used is large, you can use spectrum analysis equipment to check the noise spectrum energy distribution to identify the abnormalities. sound.
Of course, for some users, only pursuing air volume and pressure, of course, the higher the speed, the better, and the noise value can be relaxed; for system work, we always recommend choosing the low noise that meets the heat dissipation requirements, and the lower the better.
Noise: Because the blade periodically bears the pulsating force of the uneven air flow at the outlet, noise is generated; on the other hand, due to the uneven distribution of the pressure on the blade itself and the blade, the disturbance to the surrounding air and parts during rotation also constitutes rotating noise In addition, due to the gas flowing through the blades, the attached layer, the vortex and the vortex separation are generated, which cause the pressure distribution on the blade to pulsate and generate vortex noise. For fans of the same series, those with higher air volume and pressure will also have higher noise. Therefore, the fan should be selected reasonably. Excessive margin will not only waste electric energy, but also increase noise. For fans of the same model, you should try to choose a fan that runs at a low speed; for fans of different models, you should choose a fan with lower noise instead of just considering the speed.
Abnormal sound: Noise sounds only pure wind, noise is a kind of sound wave, with all the characteristics of sound wave. But the abnormal sound is different. When the fan is running, in addition to the wind, if there are other sounds (with more than two sounds), it can be judged that the fan has an abnormal sound. Abnormal noise may be caused by foreign matter or deformation in the bearing, collision due to improper assembly, or uneven winding of the motor winding, causing looseness, and abnormal noise may be generated. This kind of fan is considered to be eliminated.
