Subject: Re: VAX7000 3-phase
To: Gunther Schadow <>
From: Johnny Billquist <>
List: port-vax
Date: 03/05/2002 00:07:16
On Mon, 4 Mar 2002, Gunther Schadow wrote:

> Johnny Billquist wrote:
> > No. The first VAX to use 3-phase blowers was the 8600.
> > (Yes, it do generate a lot of heat, ECL have that property...)
> O.K. got it. In this regard it may be worth noting that
> Matt Sell had sort of complained about the 2-phase nature
> of the VAX11/78x blowers.

Hmmm. Are those really 2-phase blowers? I remember very distinctly reading
about people hooking up 11/780s to normal wall receptacles, and it worked
just fine.

> I gather that 2-phase motors
> are less efficient, and that the motors really do make a
> difference in terms of power consumption. That does of
> course not imply that the 8600 would suck less power than
> the 11/780 :-)

Believe me, it don't... While DEC was being a bit silly in using a 32A
3-phase receptacle as standard on the power line for the 8600, it do use
quite a lot of power.

> But now I completely digressed the issue from reassuring
> 3-phase-less-ness to praising the advantage of 3-phase
> motors.

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.

(By largish VAXen, I'd say I mean about 8800, 9000, 10000, apart from the
8600. Or those made by LCS? :-)


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