Selection principle:

• 1. Choose fans with high efficiency, small fan specifications and wide adjustment range to meet the acceptable performance, efficiency and quality requirements of the system.

• 2. The operating point of the fan should be near the high efficiency point of the fan to ensure stable operation and avoid the fan working in the surge zone.

• 3. To reduce the noise, we must reduce the fan speed and choose a larger fan.

• 4. The selection of a large fan often makes the fan run in a small air volume area, and the pressure difference between the inlet and outlet of the fan is large, which will cause unstable operation and noise pulsation and make a high noise.

• 5. If the fan is too small, the speed of the fan will increase, and the air will have a higher speed when leaving the blades, which will also produce higher noise.

• 6. Usually, the average wind speed at the fan outlet is 10-15m/s, and it is better not to exceed 17m/s..

• 7. Fan speed ≤450rpm, and 8-pole motor is selected; 451 ~ 799 rpm, choose 6-pole motor; 800～1500rpm, 4-pole motor; Above 1500rpm, choose 2-pole motor.

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