[rescue] Question on V490 power

Patrick Finnegan pat at computer-refuge.org
Mon Aug 25 11:03:25 CDT 2014

On Mon, Aug 25, 2014 at 2:36 AM, der Mouse <mouse at rodents-montreal.org>

> >> [...] the specs on the machine show it as 208VAC single phase power
> >> supplies only.  [...]
> > [...] another option is a step-up transformer that takes the 110vac
> > input and produces 220vac output
> Well, 220V != 208V...
> > (the V490 supplies are rated to accept 200-240vac).
> Perhaps the machine the OP was talking about has non-original power
> supplies?  208V is what you get between two legs of 120V-to-neutral
> three-phase (ideally, 120*sqrt(3), or about 207.846, volts), so if it
> really is specced for 208V, I speculate it was intended for use at a
> site with three-phase power.  (I know a hosting outfit that runs much
> of their stuff off 208V obtained from delta three-phase.)

First, I doubt that any power supply made after the 1980s is nearly that
specific. Anything that runs off of 208V will have enough supply tolerance
to run anywhere from 200-240V. (220V +/- 10%).

Also, for transformers (related to an earlier post that got snipped) since
a V890 tends to draw about 1100W in a fully-configured CPU/memory
configuration, I'd expect a V490 to draw around 1/2 of that. Maybe 600W max
average load.  So, you should be able to easily run it off of a 1kW
transformer, with plenty of room to spare.  (Power ratings on transformers
are *average* loads, not the maximum (amperage) loads that are what the
manufacturer prints on the system power supplies).

I'd be really surprised if someone went through the effort to make a
non-standard PSU for a V490 or similar system.. they're quite custom,
plentiful, and cheap compared to the rest of the machine.


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