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
5 Apr
5 Apr
6:38 p.m.
On Fri, Apr 05, 2013 at 08:18:20PM -0500, Jon Elson wrote:
The TU77 may be a problem, I vaguely recall that may
have a 3-phase
motor for the vacuum blower/air bearing pump.
Luckily no, it's just 220VAC with *insane* inrush current.
The RM07 also was 3-phase, I think all the smaller VAX
780
disks were single-phase.
RM02/03/05/80 are definitely single-phase. RP07 is 3-phase as you say,
as is RP06 and I assume therefore RP05. Dunno about RP04.
The RM07 was a total monstrosity
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.
I've heard you have to pop the RP07's top whenever it's running or it
overheats... otherwise good though, and huge for the time.
John Wilson
D Bit
6:58 p.m.
On Fri, Apr 5, 2013 at 9:18 PM, Jon Elson <elson at pico-systems.com> wrote:
The TU77 may be a problem, I vaguely recall that may
have a 3-phase
motor for the vacuum blower/air bearing pump.
I can't say for a TU77, but the TU78 is 220V.
The RM07 also was 3-phase, I think all the smaller VAX
780
disks were single-phase. The RM07 was a total monstrosity
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.
I don't remember the RM07. I remember the RM05 (CDC 9766)
and the RP07, which I _thought_ was a 100% DEC design (that
resembled a white washing machine with no access panels), but
I could be wrong about that.
-ethan
Jon
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days inactive
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elson＠pico-systems.com -
ethan.dicks＠gmail.com -
wilson＠dbit.com