| 摘要 |
PROBLEM TO BE SOLVED: To reliably protect a control source for an overvoltage protective circuit. SOLUTION: The overvoltage protective circuit has a first control source 261 generating a first power supply by using a voltage between a second phase power-supply line 42 connected to a relay 14 and a neutral-point power-supply line 44 on the side nearer to a 3-phase/4-line AC power supply 12 than the relay 14. The overvoltage protective circuit further has a second control source 262 generating a second power supply by using a voltage between a third phase power-supply line 43 connected to the relay 14 and the neutral-point power-supply line 44 on the side nearer to the 3-phase/4-line AC power supply 12 than the relay 14. A control source section 26 adopts the synthetic voltage of the first power supply and the second power supply and supplies power to an overvoltage detector 22 and a relay driving section 24. COPYRIGHT: (C)2009,JPO&INPIT
|
