Noise handling rules for cooling fans

The cooling fan speed refers to the number of times the fan blades rotate per minute, and the unit is rpm. The fan speed is determined by the number of turns of the coil in the motor, the working voltage, the number of fan blades, the inclination, the height, the diameter and the bearing system. There is no necessary relationship between the speed and the quality of the micro-fan. The speed of the fan can be measured by an internal speed signal or by an external stop.

With the change of application conditions and ambient temperature, sometimes fans with different speeds are required to meet the needs. Some manufacturers have specially designed cooling fans that can adjust the fan speed, which are divided into manual and automatic. Manual is mainly to allow users to use low speed in winter to achieve low noise, and use high speed in summer to achieve good heat dissipation. The automatic thermostat radiator usually has a temperature control sensor, which can automatically control the speed of the fan according to the current working temperature. When the temperature is high, the speed is increased, and when the temperature is low, the speed is reduced to achieve a dynamic balance, so as to reduce the wind noise. Stick to an optimal separation point with the cooling effect.

Fan noise In addition to the cooling effect, the working noise of the fan is also a common concern. Fan noise is the size of the noise generated by the fan when it is working, which is affected by many factors, and the unit is decibel (dB). When measuring the noise of the fan, it needs to be stopped in an anechoic chamber with a noise of less than 17dB, one meter away from the fan, and aligned with the air inlet of the fan along the direction of the fan shaft, and the measurement is carried out in an A-weighted manner. The spectral characteristics of fan noise are also very important, so it is also necessary to use a spectrum analyzer to record the noise frequency distribution of the fan. Generally, the noise of the fan should be as small as possible, and there should be no abnormal sound.

Fan noise is related to friction, air movement. The higher the fan speed and the greater the air volume, the greater the noise will be. In addition, the vibration of the fan itself is also a factor that cannot be ignored. Of course, the vibration of a high-quality fan will be very small, but the first two are difficult to restrain. To deal with this, we can try to use larger fans. Under the same air volume, the working noise of the large fan at low speed should be smaller than that of the small fan at high speed.

Post time: Sep-26-2022