| 摘要 |
The drive circuit 200 of a ventilation fan 34 driven by an electric motor 210 comprises: a speed control device 216 that provides an output to the motor; and commissioning circuitry. The commissioning circuitry has a calibration mode and a run mode. In calibration mode, a motor rotation speed can be adjusted to a desired value. This desired value is locked-in when the commissioning circuitry is set in the run mode. The commissioning circuitry may be toggled between calibration and run mode by a jumper 283 associated with a micro-controller 220 of the commissioning circuitry. When the jumper is connected (calibration mode), the desired motor rotation speed can be set by varying a voltage at a trim terminal 228 of the micro-controller. A plurality of preset speed settings, such as normal speed and boost speed, may be selected by toggling switches 242-245 associated with an output terminal 226 of the micro-controller, with the trim terminal being used to calibrate each of these preset speed settings in the calibration mode. The switches may determine a pulse width modulation signal output 221 by the micro-controller to command the motor speed. |
