| 摘要 |
PURPOSE:To prevent the deterioration in contacts by isolating a capacitor before changing poles for discharging the capacitor in a pole change type capacitor-operating single-phase induction motor. CONSTITUTION:A single-phase induction motor has main windings 1, 2 and auxiliary windings 3, 4 and an operating capacitor 7 is provided in an auxiliary winding circuit. A minor pole side contacts 5-1, 5-3 and multipolar side contacts 5-2, 5-4 in a change-over relay 5 are kept at ON and OFF status respectively at minor polar operation. Immediately before changing to multipolar operation from minor polar operation status by opening the contacts 5-2, 5-4, a relay contact 6 is opened to temporarily open the auxiliary winding circuit and charging electric charge stored in the operating capacitor 7 is discharged through a resistor 8. After completing discharge, the change-over relay 5 is worked and the relay contact 6 is also closed to complete the change-over operation. The same process is applied in changing to the minor polar operation. |
