Power back-up unit with low voltage disconnects that provide load shedding

摘要

A power back-up unit is provided which includes a primary power source that is connected to a plurality of loads, including a critical load and a non-critical load. A secondary power source is also provided. A first low voltage disconnect is electrically connected to the secondary power source and the critical load. A second low voltage disconnect is electrically connected to the secondary power source and the non-critical load. In one embodiment, the second low voltage disconnect disconnects the non-critical load upon loss of the primary power source. In another embodiment, the second low voltage disconnect has a voltage threshold that is greater than the voltage threshold of the first low voltage disconnect such that the non-critical load is disconnected by the second low voltage disconnect prior to the critical load being disconnected by the first low voltage disconnect.