Speed control for induction motor for fan motor, centrifugal pump motor

摘要

A three phase induction motor has triacs in the stator current paths. At least in the lower speed regime, the triacs are fired using gate control for regular and non-adjacent half waves. In the course of a speed regime, the phase angle and the spacing of the half waves is changed. Instead of being in all three phases, the triacs may be only in two stator phases, in which case the half wave spacing is an odd number. The motor is controlled with regenerative braking. The gate controller is a microprocessor.