This was originally posted on APC forums on 12/23/2011
The default for backup source 1 is generator. But, there are options to set the source type to either UPS or 'other' as well. However, the manual doesnt say anything about how the UTS will behave differently if the backup source 1 type is set to either of these alternatives. I could make some guesses about setting it to UPS but I like to know for sure. As for the purpose of 'other', I'm stumpped and the manual doesnt help either.
If I connect a large 240v UPS instead of a generator to backup source 1, would there by any reason to still use a UPS as backup source 2? If both backup sources are set to UPS and two different UPS are used for each, which would power a circuit set to 'uninterruptable'? My hope is that when source 1 is a UPS, uninterruptable circuits would be powered by source 1 and source 2 would no longer be needed at all. Can anyone confirm this?