We’re all familiar with small direct drive fans and “speed controllers”. These speed controllers are rheostats which consume, or waste, energy before it gets to the PSC fan motor, slowing the motor to a desired speed. They have been in place now for many decades in North America’s schools, offices, factories, commercial spaces, and homes. But, the consumption of energy before it even gets to the motor creates heat and is not very “green”. They are inefficient by the standards of the new technology that’s been finding its way into new HVAC systems throughout the States, Canada, and beyond.
Now that brushless DC motors, also called electronically commutated motors (ECM), are mass produced, their competitive pricing makes them the obvious choice over PSCs and rheostats.
The electronically commutated motor only uses the amount of energy necessary to obtain the desired air flow, unlike the PSCs and rheostats. They also can be adjusted from 0 rpm to 100% rpm, while the rheostats should only be adjust from 70% rpm to 100% rpm.
Furthermore, the ECMs allow for much greater flexibility in terms of speed control and operation of the fan. They can be manually adjusted with a dial on the side of the motor, manually adjusted with a remote mounted dial, or receive a 0-10 vdc control signal from the building management system. Small exhaust fans can automatically turn off or on or modulate as required.
Direct drive fans with ECMs use less electricity and are more likely to be controlled to meet the needs of the space, also saving energy dollars. Sounds like a revolution to me. For more information, click here.