1： Rotating speed is one of the fundamental determinants of various performance indicators of the fan. The unit of fan rotating speed is RPM. Chinese manufacturers generally use r/min to express it. In fact, the meaning of expression is consistent, which refers to the number of revolutions per minute of the fan blade. Fan speed is related to the number of fan blades, the number of coil turns in the motor and the working voltage, but not necessarily to the quality of the fan.

2： Air volume is the most important index used by Ventilation Fans Manufacturers to measure the heat dissipation capacity of the cooling fan. Air volume refers to the total volume of air discharged or received by the cooling fan per minute. CFM (cubic feet per minute) is generally used as the air volume unit. The larger the air volume is, the higher the heat dissipation capacity of the cooling fan is. With the same air volume, the heat dissipation effect is also related to the flow mode of the wind.

3、 Air pressure, air pressure and air volume are relative concepts. In order to make the fan have a large air volume, it is sometimes necessary to sacrifice some air pressure to complete. If a cooling fan can drive a large amount of air flow, but the wind pressure is small, the wind cannot blow to the bottom of the radiator. Therefore, we often find that some fans in life have high speed and large air volume, but the heat dissipation effect is not particularly good, because the wind pressure is low.

4、 Noise, cooling fan noise refers to the noise generated by the fan when it is working. It is affected by many factors, and the unit is decibel (dB). The noise of cooling fan is related to friction, air flow, self vibration and other factors. China Central Fans Manufacturers tell you that the higher the fan speed and the greater the air volume, the greater the noise will be. The noise of the fan mainly comes from

1. Vibration, if the physical center of mass of the rotor and the center of inertia of the shaft are not on the same axis when the fan rotor rotates, it will cause imbalance of the rotor. The closest distance between the physical center of mass of the rotor and the inertial center of the shaft is called the eccentricity. The eccentricity is caused by the imbalance of the rotor. When the rotor rotates, a force is generated on the shaft support due to the centrifugal force, and the vibration is transmitted to each part of the machine through the basic path.

2. Wind noise: when the fan is working, the blade periodically bears the pulsating force of uneven airflow at the outlet, resulting in noise; On the other hand, due to the uneven distribution of the pressure on the blade itself and the blade, the disturbance to the surrounding gas and parts during rotation also constitutes a rotating noise; In addition, the turbulent boundary layer, vortex and vortex separation are generated when the gas flows through the blade, which causes the pressure on the blade to be pulsating and generates vortex noise. Generally, the higher the air volume and pressure, the greater the wind cutting noise.