Patent ID: 8039990

Claim:
A method of manufacturing a direct current (DC) uninterruptible power supply (UPS) configured as an intrinsic power transfer switch, comprising: providing first, second, and third inputs; providing first and second rectifiers coupled to the first and second inputs; providing a common node coupled to the first and second rectifiers; and providing first DC output coupled to the common node, the first DC output adapted for connection to at least one electrical load; and providing a second DC output adapted for connection to an input of at least one other DC UPS, wherein: the first input is adapted for connection to a first electrical service, the second input is adapted for connection to a second electrical service, the third input is adapted for connection to an output of the at least one other DC UPS, and the DC UPS continues to supply power to the at least one electrical load in the event of a loss of either the first or second electrical services.