AC MORTOR STARTING BY CAPACITOR

摘要

PURPOSE: A starting condenser-shaped ac motor for high starting torque is provided to enable the generation of starting torque in initial starting by the installation of a starting condenser and a starting relay. CONSTITUTION: A triac(D1) is serially connected to a starting wire(W3). The triac is switched into one and off by the control of CPU. The first and second comparators(U1,U2) sense the voltage of both ends of the starting wire and the triac, respectively. A phase difference detecting unit detects the phase difference between voltage and current from power source applied to the starting wire by receiving the voltage. The CPU calculates the rotation speed of a motor rotor from the phase difference. Control signals are applied to a gate terminal of the triac through a driver(TD) according to calculation result.