Patent ID: 7061141
Filing Date: 2006-06-13
Classification: H02J

Abstract:
1. A method of operating in parallel a plurality of uninterruptible power supply apparatuses, each power supply apparatus having two operational modes, a bypass feeding mode for supplying power through an AC switch when an inverter in the power supply apparatus is not operating and an inverter feeding mode for supplying power from the inverter and turning off the AC switch, the method including producing an off-instruction for the AC switches in the respective uninterruptible power supply apparatuses in response to detection of coincidence of a bypass feeding signal, which is active during operation of the bypass feeding mode, and a ready signal, which becomes active when the inverter feeding mode is ready for operation, and supplying to a second of the uninterruptible power supply apparatuses the bypass feeding signal and the ready signal which are output from a first of the uninterruptible power supply apparatuses only when an on/off state signal from an output switch in the first uninterruptible power supply apparatus is in an on state.