What are the factors that need to be considered in the purchase of cooling fans? With regard to this issue, let's make a detailed explanation of the San Ju motors in Taiwan, a manufacturer of cooling fans, and learn it together.

Many businesses ignore a problem when purchasing cooling fans. All motors and electronic products that need to use a cooling fan must choose a cooling fan with enough air volume for the heat dissipation of the system, and the air volume depends on the power consumption of the system and whether enough heat can be taken away. In daily life, the service life of motors and electronic products that need to use cooling fans often decreases due to the shortage of cooling systems.Therefore, as an enterprise, it should also be understood that due to the shortage of cooling systems for cooling fans, the sales price and sales volume of motors and electronic products are often not as good as expected.Therefore, to select the correct cooling fan ventilation components, the following objectives must be considered as the standard:

First, the strongest air flow rate;

Second, the most suitable size;

Third, the quietest noise

; Fourth, the minimum power consumption;

Fifth, maximum reliability and maximum service life.

Sixth, the reasonable total cost

Having understood the above objectives and standards, we can help you achieve the above objectives through the following four steps to correctly select the cooling fan

Step 1:Total Cooling Requirements

First, three key factors must be understood in order to obtain total cooling requirements:

1.Heat that must be converted by the cooling fan ( i.e.temperature difference DT )

2.Watts ( W ) of the heat dissipation fan to offset the converted heat

3.The air volume ( CFM ) required by the cooling fan to remove heat

The total cooling requirement is extremely important for the effective operation of the system. Effective system operation must provide ideal operating conditions so that all components in the system can perform their maximum functions and the longest service life.

The following methods can be used to select a common cooling fan motor:

1.Calculate the heat generated inside the equipment.

2.Determine the allowable temperature rise range inside the equipment.

3.The equation calculates the required air volume.

4.Estimate the system impedance for the equipment.

5.Select the required cooling fan according to the characteristic curve or specification of the catalog.

If the amount of heat dissipation inside the system equipment and the allowed total temperature rise are known, the required air volume for cooling the equipment can be obtained.

Step 2:All system impedance/system characteristic curves

When the air flows, the air flow will meet the obstruction of the internal parts of the system in its flow path, and its resistance will restrict the free flow of air. The change in pressure is the measured static pressure.

In order to confirm the cooling wattage between each slot, the design or manufacturer of the cooling fan system must not only have the effective cooling fan characteristic curve of the cooling fan to determine its maximum air volume, but also know the wind resistance curve of the system. Parts inside the system can cause loss of wind pressure. This loss varies with the air volume, the so-called system impedance.

Step 3:System Operation Work Point

The intersection of the system characteristic curve and the cooling fan characteristic curve is called the system operating point, which is the optimal operating point of the cooling fan.

Step 4:Noise Value

The noise of the cooling fan is measured in a reverberation-free room with a background noise of less than 15 dBA. The cooling fan to be tested runs in free air and disposes of a noise meter one meter from the air inlet.

The following seven guidelines provide the best way to use a cooling fan to reduce noise to a minimum:

1.System impedance

The range between the air inlet and the air outlet of a casing accounts for 60 % to 80 % of the total system impedance, and the larger the airflow, the higher the noise. The higher the system impedance, the greater the airflow required for cooling, so in order to minimize noise, the system impedance must be minimized.

2.Air turbulence

Disturbances caused by obstacles encountered along the air flow path can generate noise. Therefore, any obstruction, especially in the critical air inlet and outlet areas, must be avoided in order to reduce noise.

3.Speed and size of cooling fan

Since the high-speed cooling fan generates more noise than the low-speed cooling fan, the low-speed cooling fan should be tried and selected as much as possible. However, a cooling fan with larger size and lower rotating speed is usually quieter than a cooling fan with smaller size and higher rotating speed when delivering the same air volume.

4.Temperature rise

In a system, the air volume required for cooling is inversely proportional to the allowable temperature rise. If the temperature rise is allowed to increase slightly, the required air volume can be greatly reduced. Therefore, if the restrictions imposed on the allowable temperature rise are slightly relaxed, the required air volume and noise can be reduced.

5.Vibration

In some cases, when the weight of the whole system is very light or the system must operate according to certain regulations, it is especially recommended to use soft insulation equipment to avoid the transmission of vibration of the cooling fan.

6.Voltage variation

Voltage variation will affect the noise level. The higher the voltage applied to the fan, the greater the vibration and the greater the noise due to the increase in the rotational speed.

7.Design considerations:

The design of every part that makes up the cooling fan will affect the noise level.

Taiwan's Three Giant Warm Tips:Choosing the right cooling fan for your electronic products can effectively reduce product energy consumption and prolong equipment service life