一般情况下离心风机就是用来通风的，那么实现风量调整的就是电机，不同的风量就会有不同的电机风机类型，接下来看一下在不同的应用场景下离心风机的选型原则。

　　In general, centrifugal fan is used for ventilation, so the motor is used to adjust the air volume. Different air volume will have different motor fan types. Next, let's take a look at the selection principle of centrifugal fan in different application scenarios.

　　1.选用效率较高，离心风机规格较小，调节范围较大的风机，来满足系统可接受的性能，效率和质量要求。

　　Select the fan with higher efficiency, smaller size and larger adjustment range to meet the acceptable performance, efficiency and quality requirements of the system.

　　2.风机运行工作点，应选择在风机效率高点附近，以确保运行稳定，避免风机在喘振区工作。

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

　　3.要降低噪声，降低离心风机转速，选择较大的风机。

　　To reduce noise and reduce the speed of centrifugal fan, select larger fan.

　　4.过大风机选择，往往使风机运行在小风量区，风机进出口压差大，会引起运行不稳定和噪声脉动，发出较高噪声。

　　The selection of over fan often makes the fan run in the 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 emit high noise.

　　5.过小风机选择，会引起风机转速提高，空气在离开叶片时有较高速度，也会产生较高噪声。

　　If the fan is too small, the speed of the fan will be increased, and the air will have a higher speed when leaving the blade, which will also produce higher noise.

　　6.通常风机出风口平均风速在10-15m/s，尽量不要超过17m/s。

　　Generally, the average wind speed of fan outlet is 10-15m / s, and it should not exceed 17m / s.

　　7.离心风机转速≤450rpm，选8级电机；451～799rpm，选6级电机；800～1500rpm，选4级电机；1500rpm以上的，选2级电机。

　　Select the motor with the speed of 454-1500rpm and the motor with the speed of 454-1500rpm.

　　离心风机选型的时候也不要只看它的大小，因为电机作为一个制动装置，它在风机中起到重要的作用，如果电机不能符合是要求，那么就不能满足使用需求，尤其是需要风机风量较大的时候，这种情况下电机是不能良好运行的。

　　When selecting the type of centrifugal fan, do not only look at its size, because the motor as a braking device, it plays an important role in the fan, if the motor can not meet the requirements, then it can not meet the use requirements, especially when the fan air volume is large, the motor can not operate well in this case.