sharing a power supply

Jim Lux James.P.Lux at
Fri Jul 4 13:55:34 EDT 2003

If quiet and compact is your goal, then maybe getting some standard smaller
supplies and doing some repackaging might be a better solution.  Pull the
fans out of the small supplies, mount them with some ducting and use 1 or 2
larger diameter fans.  In general a larger diameter fan will move more air,
more quietly, than a small diameter fan.

You're already straying into non-standard application of the parts, so
opening up the power supplies is hardly a big deal.  You might find that
using 3 small 200W supplies might be a better way to go than 1 monster 450W

There are also conduction cooled power supplies available (no fans at all)

----- Original Message -----
From: "Alan Ward" <award at>
To: "Alvin Oga" <alvin at>
Cc: <beowulf at>
Sent: Friday, July 04, 2003 12:53 AM
Subject: Re: sharing a power supply

> Hi Alvin
> En/na Alvin Oga ha escrit:
> (snip)
> > 450W power supply doesnt mean anything ...
> > its the total amps per each delivered voltages
> > that yoou should be looking at  and how well you
> > want it regulated ...  there's not much room
> > for noise on the +3.3v power lines and it uses
> > lots of current on some of the memory sticks
> I am. As has been noted, it looks like there's very
> little draw on 3.3V; we are way above specs.
> You are right about 5V and spikes, though. Have to
> try and see. Luckily, I have no other 5V devices
> in the box (I think :-).
> This 450W is given for 45A/5v and 25A/3.3V, with a
> 250W limit across these two lines.
> > if the idea of hooking up 4 systems to one ps was
> > to reduce heat and increase reliability, i think
> > using multiple systems on a ps designed for one
> > fully loaded mb/system will give you the opposite
> > reliability effect
> This is a small mobile console type system, on wheels.
> The idea is to move it around from one desk to another,
> so different people can litteraly get their hands on it.
> Having little noise (thus fans) is about as important
> as pure computing power at this stage - I need to have
> them buy the concept first. The design isn't too bad;
> the pics will be on the web ASAP.
> Best regards,
> Alan
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