Common technical indicators of cooling fans

1. Air volume

       Air volume refers to the total volume of air exhausted or taken in by the cooling fan per minute. If calculated in cubic feet, the air volume unit is CFM; if calculated in cubic meters, it is CMM. The air volume unit commonly used for cooling fans is CFM (about 0.028 cubic meters/minute). 

Air volume is the most important indicator to measure the heat dissipation capacity of a cooling fan. Obviously, the larger the air volume, the higher the heat dissipation capacity of the cooling fan. This is because the heat capacity ratio of air is certain, and the larger the air volume, that is, more air per unit time, can take away more heat. Of course, under the same air volume, the heat dissipation effect is related to the flow mode of the wind.

2. Wind pressure

       Wind pressure and air volume are two relative concepts. Generally speaking, in order to save costs, manufacturers will sacrifice some wind pressure when designing a fan with a large air volume. If the fan can drive a large amount of air flow in the heat sink, but the wind pressure is low, the wind will not reach the bottom of the radiator (this is why some fans have high speeds and large air volumes, but the heat dissipation effect is poor). On the contrary, high wind pressure often means low air volume, and there is not enough cold air to exchange heat with the heat sink, which will also cause poor heat dissipation effect.

3. Cooling fan

4. Fan speed

       Fan speed refers to the number of times the fan blades rotate per minute, measured in rpm. Fan speed is determined by the number of turns in the motor coil, the operating voltage, the number of fan blades, the inclination angle, the height, the diameter and the bearing system. There is no necessary connection between speed and fan quality. The fan speed can be measured by an internal speed signal or externally. 

       As the application and ambient temperature change, fans with different speeds are sometimes needed to meet the needs. Some manufacturers have specially designed cooling fans with adjustable fan speeds, which are divided into manual and automatic types. The manual one mainly allows users to use low speeds in winter to get low noise, and use high speeds in summer to get good cooling effects. Automatic thermostatic radiators generally have a temperature control sensor that can automatically control the fan speed 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 that wind noise and cooling effects maintain an optimal combination point.

5. Fan noise

       In addition to the heat dissipation effect, the working noise of the fan is also a common concern. Fan noise is the size of the noise generated when the fan is working. It is affected by many factors and is measured in decibels (dB). When measuring the noise of the fan, it is necessary to measure it in a soundproof room with a noise level less than 17dB, one meter away from the fan, and align the fan's air inlet along the direction of the fan shaft, and use A-weighted method to measure. The spectral characteristics of the fan noise are also very important, so it is also necessary to use a spectrum analyzer to record the frequency distribution of the fan noise. Generally, the fan noise is required to be as small as possible and there should be no abnormal sound. The fan noise of the cooling fan is related to friction and air flow. 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 overcome. To solve this problem, we can try to use a larger fan. Under the same air volume, the working noise of a large fan at a lower speed should be less than the working noise of a small fan at a high speed. Another factor that we tend to overlook is the fan bearing. Since the shaft and bearings will rub and collide when the fan rotates at high speed, it is also a major source of fan noise.

Application of cooling fans

       Widely used in computers, communication products, optoelectronic products, consumer electronics, automotive electronic equipment, switches, medical equipment, heaters, air conditioners, inverters, ATMs, car refrigerators, welding machines, induction cookers, audio equipment, environmental protection equipment, refrigeration equipment and other traditional or modern instruments and equipment.

       Shenzhen Dongweifeng Electronic Technology Co., Ltd. was established in 1991. It is a national high-tech enterprise. It has now developed into a professional supplier of cooling solutions and products for computers, electronics, etc. The company has successfully passed ISO9001:2000 quality system certification, ISO14001:2004 environmental system certification and UL. TUV. CE product certification. As a national key high-tech enterprise focusing on R&D, manufacturing and sales, it has formed three pillar industries: computer electronic radiators, cooling fans; LED lighting, outdoor landscape lighting engineering lighting; and architectural decorative panels.