| 摘要 |
PROBLEM TO BE SOLVED: To increase reliability in operation by preventing interphase short- circuit accidents in a system, caused by the erroneous connection of an external cable, thereby avoiding emergency shutdown of a feeding system. SOLUTION: Input terminals 3a, 3b of a distribution board 3, an uninterruptible power supply unit (USP) 4, and a bypass route of a commercial power source 1 are connected through the outside cables 5, 6, a distribution board includes a breakers 3d, 3f, and a switch 3g disconnecting the circuit of a bus 3e on the bypass route side so as to be fed through the USP. This uninterruptible feeding system is formed so as to usually feed electricity to a load through the distribution board from the USP, and switches the feed through the bypass route when the maintenance of the USP, wherein the distribution board includes a protective relay 7 detecting the erroneous connection of the external cable and disconnecting the switch 3g forcibly and a warning buzzer 8. Concretely, between the input terminals 3a and 3b on the distribution board, the protective relay and the warning buzzer are connected across between buses of the identical phase (R-phase). |
