UPS buying suggestion

Erich Dollansky erich at
Tue Oct 15 12:42:43 UTC 2013


On Tue, 15 Oct 2013 13:59:28 +0200
Ralf Mardorf <ralf.mardorf at> wrote:

> On Tue, 2013-10-15 at 13:48 +0800, Erich Dollansky wrote:
> > As you need the current anyway, I would use an ampere meter to
> > determine the exact current drawn. I got already some surprises
> > there.
> You can do a Ampere measurement, but that doesn't help you, you need
> to measure the consumption over a longer period.
> Regarding to the hair dryer, it's an electromotor ;).

Which is still harmless compared to the peaks switching power supplies
might have even if the power factor is high. I was surprised myself that
the hair-dryer worked on one after it 'failed' dramatically on the other

Still, the most extreme experience related to power factor I ever got
was at the beginning of my professional education. A relatively small
electrical device has had such a low power factor that its connection to
the power outlet made the distrubution panel fly out of the wall. This
made me going parnoid about the power factor. As this device was a
prototype, some changes have been made before it reached the public.


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