| 摘要 |
PURPOSE:To easily and accurately discover the occurrence of the ground fault of a battery constituting an uninterruptible power unit due to a leakage liquid from the battery. CONSTITUTION:An earth leakage breaker 11 is installed to the AC input circuit of a rectifier 3 constituting an uninterruptible power unit as an AC ground-fault current detecting means or the breaker 11 is installed to the input circuit of a battery 6 as an AC ground-fault current detecting means. In either case, one line of the AC input circuit of the rectifier 3 is connected to the ground through a grounding capacitor when an AC power source 2 is of a non- grounding system. When the battery 6 causes a ground fault due to a leakage liquid, the ground-fault current flowing between the ground-fault point and the grounding section 2E of the power source 2 or between the ground-fault point and grounding capacitor flows to the breaker 11 as an unbalanced current. Therefore, the ground fault of the battery 6 can be easily and accurately detected. |
