On Fri, 2008-05-02 at 14:21 -0500, Mikkel L. Ellertson wrote: > g wrote: > > > >> On Wednesday 30 April 2008 01:00:32 pm Mikkel L. Ellertson wrote: > >>> It could be the time it take to switch between line power and > >>> battery. It tends to be more common with fully loaded power > >>> supplies. There is not enough reserve in the filter caps or > >>> something to carry over the loss of a cycle or two. A UPS that > >>> will also compensate for line voltage tends to have less of a > >>> problem with this because there isn't the abrupt changeover. > > > > this is incorrect. ups = uninterruptible power supply. > > > > dc to ac conversion is done with mains floating battery and ac conversion > > circuit draws power form battery. this is what maintains continuous ac > > output with out interruption. > > > > > It is supposed to be uninterpretable, but in practice, low end UPSs, > especially the ones sold for home or home offices, have a changeover > time when AC fails. It is only a cycle of so, but it is there. They > are not designed to be providing continuous AC. These units should > properly be called a battery backup, and not a UPS, but you know how > marketing is. > > I have worked with true UPSs, but most of those were 480 volt, 3 > phase, with a room full of batteries... > Hi, Mikel, A few years ago you were right... But today, most have the internal capacitors and a relatively common chipset so that they typically don't miss cycles, but perhaps a fraction of a cycle. To be sure, a purchaser should read the specs, but most will meet the needs of a home user with no problem, providing the batteries are kept up (meaning checked or changed annually or so.) Regards, Les H -- fedora-list mailing list fedora-list@xxxxxxxxxx To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list
