5 Apr
2013
5 Apr
'13
6:18 p.m.
Date: Fri, 05 Apr 2013 16:06:58 -0400
From: Dave McGuire <mcguire at neurotica.com>
To: General Discussion: On-Topic and Off-Topic Posts
<cctalk at classiccmp.org>
Subject: Re: VAX 11/780
Message-ID: <515F2EE2.6020902 at neurotica.com>
Content-Type: text/plain; charset=ISO-8859-1
On 04/05/2013 03:37 PM, Brian Roth wrote:
The blowers?
Nope, the entire machine is built from single-phase components.
The power supplies even have wall plugs on them, and are powered through
what are essentially the female end of extension cords. (I think they
run off 208 V, but maybe they were running L-N off of 120 V.)
The blowers were 208/230 V single-phase motors, you could hear the
centrifugal switches drop back in when you shut the machine off.
The power distribution wiring would have to be hacked for single-phase
operation, hopefully the power supplies can be run off 240 V without
harm.
The TU77 may be a problem, I vaguely recall that may have a 3-phase
motor for the vacuum blower/air bearing pump. Today, I'd get
a VFD and run the motor (ONLY) off synthetic 3-phase.
The RM07 also was 3-phase, I think all the smaller VAX 780
disks were single-phase. The RM07 was a total monstrosity
Agreed. The one place I am going to start is with the power supplies. I plan on running
this on
single phase at least initially. I don't see anything in there that needs 3 phase.
from Burroughs, I hope you don't have one of those.
We went through
a lot of pain as one of the early adopters of that, but in the
end it was a high performance drive and fairly reliable.
Jon