Another option is an EC (electronically commutated brushless) motor system. The horsepower range of EC motors has increased to a maximum of about 3/4 hp in recent years. The motors' superior efficiency, added control, and flawless reliability are said to offer interesting solutions to HVAC projects. However, there is an added complexity when EC drive electronics are remote from the motors.
The company says its latest EC motor generation addresses this problem. All electronics are now completely within the envelope of the fan motors. The OEM or the contractor simply applies the a.c. power and either a 0- to 10-V or RS485 control signal. Some EC motors even have a controller for a PID closed-loop process control internally on board. An advanced commutation method assures extremely smooth fan operation. In addition, the EC motor performance range has been extended to 4 hp (3 kW) / 177 lb-in (20 Nm). The company says that this new range of EC motors helps to meet tough noise and efficiency specs for rooftop condensers and air-handling units.
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