Downsizing motor that drive fans

[Ming1992]

Hi, I am facing some problem

can i just downsize the motor that drive the fan as currently the fan is operated at full load but the flow rate is controlled by a damper.
my thought is that is it possible to downsize the motor so it will operate at lower rpm therefore we no longer need to use damper to control the airflow.

the implication to it is to lower down power consumption of the motor.

 

[rollingstein]

Use a VFD?

 

[russ_watters]

Rpm isn't a function of size for most AC motors, but you can select from several typical RPMs.

If the fan is belt driven, you could also resize the pulleys.

 

[mark.watson]

Using a smaller motor won't necessarily mean a lower rpm: it means less horse power. If you want to use a smaller motor, you must first determine your desired volumetric flow rate, and then look at the fan curve for that particular fan to see what minimal motor horse power you need.