How to Adjust the Airflow and Air Pressure of AC Centrifugal Fans?

Precise control of airflow and air pressure is achieved through speed adjustment.

In AC centrifugal fans, the most direct and economical way to adjust airflow and air pressure is to change the fan speed.

1. Application of Variable Frequency Drive (VFD) Technology

Modern centrifugal fans are usually equipped with variable frequency drives (VFDs), which allow for stepless adjustment of airflow by changing the motor speed. Since airflow is directly proportional to speed, and power is proportional to the cube of the speed (P∝N³), significant airflow control can be achieved with only slight speed adjustments, while maintaining high efficiency.

2. Impeller Design and Speed ​​Relationship

The impeller design of an AC centrifugal fan determines its optimal operating point at a specific speed. Forward-curved blade designs, such as those produced by Ningbo Haoyue Fan Manufacturing Co., Ltd., typically provide higher air pressure at high speeds; while low-speed operation helps reduce noise and extend lifespan.

3. System Matching and Fluid Characteristics

When adjusting the speed, the resistance curve of the entire HVAC system must be considered. Since air pressure and airflow are not linearly related, the fan's characteristic curve needs to match the pipe network's characteristic curve to ensure stable operation after speed adjustment.