X config damaged by power failure
Les
hlhowell at pacbell.net
Fri May 2 19:26:41 UTC 2008
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
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