| 摘要 |
PROBLEM TO BE SOLVED: To replace a power supply unit without interrupting the operation of a device. SOLUTION: A CPU substrate unit 36 and an auxiliary relay unit 38 are powered from a plurality of power supply units 18, 20 through switches 24, 26, 32 and 34. If a system accident is detected by the CPU substrate unit 36, a trip command is outputted from the auxiliary relay unit 38 to a breaker. To replace one of the power supply units 18, 20, for example, the power supply unit 18, the switches 24, 26 are opened with power from the power supply unit 20 supplied to a load. Thus, the power supply unit 18 can be replaced without the need for stopping the device, that is, with a protective relay function connected. |
