Electric power system with maintenance bypass for uninterruptible power supply using closed transition operation

Abstract

An uninterruptible power source having a static transfer switch which switches rapidly between a commercial power source and an alternate power source is removed from service by a maintenance bypass switch having a first switch in series with the uninterruptible power source and a second switch which shunts the uninterruptible power source and the first switch. The first and second switches are circuit breakers having handles which toggle between open and closed positions. The maintenance bypass switch includes an operator which operates the two circuit breakers in opposition with a closed transition so that one switch is always closed. An interlock prevents operation of the maintenance bypass switch when the alternate power source of the uninterruptible power supply is selected by the static transfer switch. An isolation switch between the uninterruptible power source and the commercial power source and also shunted by the second switch of the maintenance bypass switch is open together with the first switch of the maintenance bypass switch when the uninterruptible power source is to be isolated for maintenance.

Dependencies are inferred from the claim text.