This unit safeguards equipment from primary mains supply failure. In normal operation, the outputs are supplied from the primary (A) supply.
If the primary supply fails, the relay switches to the secondary supply (B). The relay switches at ~25ms and the small glitch on the mains supply is dealt with by the power supplies in the powered equipment. The result is that the units remain powered without problems. This is especially true of any computers connected to the MDU.
The two mains supplies may be independent but must be of the same phase. On the return of the primary supply, the unit will switch back to primary power ‐ again without problems.
The mains indicator is electrically after the relay and before the fused outputs and verifies input voltage is present. The unit is designed for total power loss. The status of the unit is remotely available via a 9‐way D‐type on the rear panel. Relay contacts report on: input A selected, input B selected and power available to output array.
This unit is housed in a sturdy 19" 1 RU racked mounted enclosure, 195mm behind panel depth (300mm including lacing bar). The front panel comes in a standard semi‐gloss black finish(RAL9005), with wide clip-on designation strip for clear marking.