| 摘要 |
PROBLEM TO BE SOLVED: To provide an uninterruptive power supply unit capable of stopping power supply to a load if the commercial power source of a direct supply bypass fails, while maintaining and inspecting an AC switch circuit through a route from a direct supply bypass circuit to a maintenance bypass switching circuit and the load. SOLUTION: This uninterruptive power supply unit it provided with a switching circuit 6, connected between a connecting point A of CVCF1 and an AC switching circuit 4 and a connecting point B of a direct supply bypass circuit 3 and a maintenance bypass switching circuit 5, and a switching circuit 7 connectedly inserted in series between the connecting point B of the direct supply bypass circuit 3 and the maintenance bypass switching circuit 5 and an input end 31 of the direct supply bypass circuit 3. The switching circuits 6, 7 is equipped with interlock function. When an AC switch circuit 4 is maintained and checked, power supply to a load 8 can be conducted in such a condition that the output of the CVCF1 is fed without use of the direct supply bypass, so that adverse effects will not be given to the load 8, even if a commercial power source fails during maintenance and inspection. |
