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.

 

[alphy]

I understand your concern about downsizing the motor that drives the fan. While it may seem like a simple solution to reduce power consumption, there are several factors that need to be considered before making such a decision.

Firstly, downsizing the motor may lead to a decrease in the power output of the fan, resulting in a decrease in the airflow. This could potentially affect the performance of the system and may not be suitable for certain applications. It is important to carefully calculate and determine the appropriate motor size to ensure that the airflow remains at the desired level.

Additionally, downsizing the motor may also affect the efficiency of the fan. A smaller motor may not be able to achieve the same level of efficiency as a larger motor, resulting in higher energy consumption and potentially negating any benefits of downsizing.

Furthermore, removing the damper and relying solely on downsizing the motor to control airflow may not be a feasible solution in all cases. The damper serves an important purpose in regulating the airflow and maintaining a stable system. Removing it may lead to instability and potential damage to the fan and motor.

In conclusion, while downsizing the motor may seem like a simple solution to reduce power consumption, it is important to carefully consider all the implications and conduct thorough calculations before making any changes. It is also recommended to consult with a professional engineer or expert in the field to ensure that the system will continue to operate efficiently and effectively.