1. System Impedance

The range between the inlet and outlet of a casing occupies 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 to minimize noise, the system impedance must be minimized.

2. Airflow disruption

The turbulence caused by obstructions encountered along the airflow path creates noise. Therefore, any obstacles, especially in the critical inlet and outlet areas, must be avoided to reduce noise.

3. Fan speed and size

Since high-speed fans generate more noise than low-speed fans, try to use low-speed fans whenever possible. A fan with a larger size and a lower rotating speed is usually quieter than a fan with a lower size and a higher rotating speed when delivering the same air volume.

4. Increased temperature

In a system, the amount of air required for cooling is inversely proportional to the allowable temperature rise. Allowing a slight increase in temperature rise can substantially reduce the amount of air required. Therefore, if the restriction imposed on allowable temperature rise is slightly relaxed, the required air volume can be reduced and the noise can be reduced.

5. vibration

In some cases, when the weight of the entire system is very light, or the system must be operated according to a certain stipulated method, it is particularly advisable to use a soft insulation device in order to avoid the transmission of fan vibration.

6. Voltage change

Changes in voltage can affect the noise level. The higher the voltage applied to the fan, the higher the speed, the greater the vibration and the greater the noise generated.

7. Design considerations

Each part of the fan design will affect the noise level. The following design considerations can achieve noise reduction: the size of the winding core, the design of the blades and the frame, and the precise manufacturing and balancing.