| 摘要 |
PURPOSE:To prevent rush current upon starting by a method wherein the capacitor of a smoothing circuit is charged upon starting through auxiliary switches, inserted in parallel to main magnetic contactors, and auxiliary circuits, to which resistors are connected in series. CONSTITUTION:A rectifying circuit, consisting of three-phase full-wave bridge type diodes D, is connected to a smoothing circuit, consisting of choke input type inductor L and capacitor C, and main electromagnetic contactors MC1 are connected to the input side of 3-phase AC of the rectifying circuit while auxiliary circuits, consisting of an electromagnetic contactor MC2 and a resistor R2 connected in series, are connected in parallel to the main electromagnetic contactors MC1. A control circuit CC, closing the auxiliary electromagnetic contactor MC2 upon commanding starting while closing the main electromagnetic contactor MC1 when the output voltage Vc of the smoothing circuit becomes higher than a predetermined value V1, is provided. The capacitor of the smoothing circuit is charged through the auxiliary circuits, equipped with the auxiliary switches MC2 having comparatively small current capacity and the resistors R2. According to this method, rush current upon starting may be prevented. |
