Subject: Re: VAX7000 3-phase
To: John Wilson <>
From: Johnny Billquist <>
List: port-vax
Date: 03/05/2002 09:49:15
On Mon, 4 Mar 2002, John Wilson wrote:

> >From: Johnny Billquist <>
> >Well, I believe that just about all VAXen except 8600 (and perhaps other
> >really largish VAXen) will work just fine on single phase.
> >I can't really imagine anything needing 3-phase except motors, in these
> >things. And the 6000-machines don't use those kind of motors anyway. I
> >would suspect the 7000 are about the same thing.
> Not to fan the flames but:  in the DEC-2065 power supply, there really
> honestly IS a three-phase transformer followed by a six-diode bridge
> rectifier, for at least one of the weird ECL voltages (I forget the details
> but I dug through the schematics when I was hoping to get one of these
> monsters running in my garage).  I guess they really cared about ripple...

Last time I looked at our DEC-2060, it didn't say "VAX" anywhere. :-)

But you are correct in that in some machines DEC have built, the power
supplies really require 3-phase. But that's only as far as the ps
goes. Beyond that, there is no need. So you could hook into the actual
feeds to the machine instead, using your own PS. But that is beyond my
knowledge anyway. :-)

However, perhaps the biggest power sucker in the -2060 (and I assume the
-2065) is the power supply for the memory boxes, which aren't even
switched PSes... (or was it those you were talking about?)

Oh, and our -2060 were hooked directly into 3-phase 63A @ 310V.
That was a bit overkill though. :-)


Johnny Billquist                  || "I'm on a bus
                                  ||  on a psychedelic trip
email:           ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol