[NCLUG] Linux on Sun Hardware

[Jim Wildman]

Tell him you are only installing half that many...then add away. :-).
Regs can be sticky about such things.  

There will be some spinup surge from the drives, but once they are
spinning, it doesn't take much.  It would be a really bad regulator that
pulled its full amperage all the time.  If it isn't being used, then it
is being dissipated as heat...which is bad.

An ammeter is the best idea for finding out what it is really using.
Each box should be fused at its rated amperage as well, so if some burns
out/locks up, the fuse blows.

watts out = volts x amps in x power factor x efficiency

The power factor can be considered to be 1, and that leaves the
efficiency of the power supply.

Whatever it is drawing from the AC is directly related to what the
various components are using.

------------------------------------------------------------------------
Jim Wildman, CISSP                                      jim at rossberry.com
817-308-3868                                     http://www.rossberry.com

On Wed, 23 Jan 2002, Michael Dwyer wrote:

> Yeah, right now we're looking to wire up 140 Pentium ~90 computers here
> at the office.  Each nameplate says 3 amps.  Unfortunatly, our
> electrician has to believe that.  But I hooked one up to a meter, and I
> only saw, like, one tenth of that.  I expect the startup is a little
> steep, trying to spin up those ancient drives... but I strongly believe
> that there is no way those things are drawing 3 amps each...
> 
> FWIW, if I read things right, a basic voltage regulator always pulls its
> rated amperage, even when it is not loaded...  Does that sound right? 
> It doesn't to me... But anyway, that might be where the confusion is
> coming from.
> 
> So, could it be said that testing the draw of a power supply is a good
> measure of load on the power supply?  That is, if I have a power supply
> that is rated to 3 amps, and it is currently drawing two, is it safe to
> assume that I can probably hang another drive off that power supply
> without problem?
>