Transient Characteristics of Tapped-Winding Capacitor Motor

Abstract

Tapped-winding capacitor motor is widely used to drive a shaft-mounted fan. In this motor the burnout accident of phaseshifting capacitor sometimes happens. The cause of this accident is considered to be the transient capacitor current. In this paper, equations Sir calculating transient characteristic are derived in 3 types of tapped-winding capacitor motors. Based on these equations, transient characteristics are clarified in high-speed winding connection and low-speed winding connection. Further, from the designing viewpoint, effects of turns ratio and capacitance of capacitor on the transient characteristics are examined and the procedure for choosing winding ratio and capacity is suggested. The transient current is shown to decrease by about 40% by this method.