A few decades ago I worked with some quite large Telecom gear that ran from 208 volt AC. The equipment had its own internal 48 volt supplies and short term battery back up system (basically so the redundant CPU units could gracefully shut down in the event of a power failure.) The manufacturer also sold similar systems that ran from customer supplied 48 volts but many enterprise customers who already had large UPS systems and back up generators preferred the versions that ran from 208 volt AC.
Some smaller office phone systems back in the early 1990's also featured large external battery packs to get multi hour run times. The vendors would typically send technicians out to peridoically check the battery systems. The few that I was able to examine were typically made up from 2 volt sealed lead acid cells. The used cells used to be some what available to hobbyists as the tended to get replaced before they failed. Yes some large UPS systems don't work very well at supplying low levels of power for long the periods. During a multi hour maintenance shut down at work a few decades ago we had one device that we hoped to keep running (essentially a small digital voice play back unit that played phone system messages, ie. "The number you have reached is not in service.") It drew well under 100 watts and was the only load at the time for a large UPS system with multiple battery banks which stopped running after a few hours and I had to re record the messages. None of us were very surprised. Mark Spencer m...@alignedsolutions.com 604 762 4099 > On Sep 26, 2020, at 12:33 AM, Hal Murray <hmur...@megapathdsl.net> wrote: > > >>> Can't I just use a high quality APC backup power system >>> like we use to power racks of gear in our Telco and compute closets? > >> Very few UPS's are good at long-run applications, they are typically built to >> run a heavy load for minutes, not a tiny load for hours or even days on end. > > That matches my expectations, but somebody might expect their telco gear to > stay up longer than the few minutes it takes to cleanly shut down a computer. > > Is there a branch of UPS gear aimed at telco rather than computers? That is > good efficiency at low power and long time rather than high power for short > time. > > Does all telco gear that is expected to run off UPS take 48V? > > Is there a market in small 48V supplies with UPS option for the telco market? > > You would have to build a 48V to 24V converter rather than the whole thing. > You can probably get a brick for that. > > > > -- > These are my opinions. I hate spam. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
