| 摘要 |
PROBLEM TO BE SOLVED: To provide a circuit that effectively suppresses a rush current passing when three-phase power is applied and prevents breakdown of a rectifying device and a smoothing capacitor. SOLUTION: A relay 3 for charging a smoothing capacitor 6 is provided at least in two phases in parallel with a three-phase electromagnetic switch 2, and a rush current prevention resistor 4 is provided in series with the relay 3 for charging. When a three-phase alternating-current power source 1 is turned on, the smoothing capacitor 6 is charged through the relay 3 for charging and the rush current prevention resistor 4. After a predetermined time has passed, the smoothing capacitor 6 is charged through the three-phase electromagnetic switch. Thus, the elements in a rectifying circuit 5 or the smoothing capacitor 6 is prevented from being broken down by a rush current passing when the three-phase alternating-current power source is turned on. COPYRIGHT: (C)2006,JPO&NCIPI |
