Uninterruptible power supply

摘要

A battery of an uninterruptible power supply unit 1a is configured by at least two batteries (a first battery 2 and a second battery 21a). A control circuit 12a judges opened/closed states of a first cover 6a and a second cover 25a on the basis of information from a first cover-opening detecting device 7a and a second cover-opening detecting device 11a. When the first cover 6a is opened, a first switch 8 which connects a charge and discharge circuit 3 to the first battery 2 is opened, and, when the second cover 25a is opened, a second switch 10 which connects the charge and discharge circuit 3 to the second battery 21a is opened.