CALIBRATION TECHNIQUE FOR VARIABLE SPEED MOTORS

摘要

CALIBRATION TECHNIQUE FOR VARIABLE SPEED MOTORS A variable speed motor is regulated responsive to the load torque acting on the blower wheel. The load torque acting on the blower wheel is determined by means of a coast down procedure in which the motor is briefly de-energized and the rate of angular change d.omega./dt is determined. The load torque acting on the blower wheel can be determined knowing the moment of inertia and d.omega./dt. The average motor RPM during the coast down is then related to a torque value where an RPM vs. CFM relationship has been empirically determined for that blower wheel. A microprocessor then computes the final motor RPM necessary to achieve the desired air delivery (CFM) using the fan law equations.