| 摘要 |
PURPOSE:To improve the power factors at the starting time and at the start completion time of an induction motor by altering the capacity of a power factor improving capacitor at the starting time and the operating time. CONSTITUTION:When a starting switch 5 is closed, the coils 210, 220, 230 of the first to third electromagnetic switches are simultaneously excited, the first to third electromagnetic switches 21, 22, 23 are closed to connect a capacitors 41, 42 to a circuit. Simultaneously, a time limit relay 6 is also excited, and after the prescribed time is elapsed, it is operated to deenergize a coil 220 of the second electromagnetic switch, the second electromagnetic switch 22 is opened to isolate the first capacitor 41 from the circuit. In this manner, the low power factor at the starting time and the power factor after the start is completed can be improved. |
