The Hoffman Controls 792-ECM Series Electronic Motor Speed Controller is designed to provide proportional speed control for energy efficient ECM (brushless dc) motors for variable air volume applications. The input is a DC voltage or current and the output is a PWM signal. The 792-ECM (VmA) Series is line voltage independent and requires only a 24 VAC power source.
Motor speed control is accomplished via a pulse width modulated signal from the 792-ECM which drives the ECM motor through it’s dedicated control signal input.
The 792-ECM also provides a motor enable signal that is active whenever motor operation is indicated by control signal source. The 792-ECM has identical function with the 791-ECM but does not provide this GO signal or the manual speed adjustment described below.
The controller modulates the output pulse width to regulate RPM as determined by a 2-10VDC or 4-20mA DC input signal provided by the customer. There is also a manual speed adjustment to aid in setup or flow calibration tasks. A continuous flow level can be achieved with the manual speed adjustment biasing the motor on at your desired level. Variable speed operation will automatically resume when the input signal exceeds the manual speed setting.
- This variable speed controller is used for adjustment of motor RPM. The controller is designed for air moving applications using squirrel cage or propeller type fans. It may be suitable for other, non air-moving, direct drive motor applications.