14 Jul
2021
14 Jul
'21
6:39 a.m.
The LSSM, VCFed and System Source acquired a large collection of VAX
hardware couple of years ago and divided it up for their various museums
(6000? 7000?). There is very little about it online, but I have
seen the portions that made it to vcfed and System Source. If it wasn't a
very large 6000 array, it was something contemporary and there was a
plethora of terminals, parts, cabinets that would have been
6000-compatible. You should ask someone at VCFed to take a look at what
they have in the warehouse. Also the Rhode Island computer museum may have
some 6000 stuff, I was just there.
Bill
On Wed, Jul 14, 2021 at 9:21 AM Paul Koning via cctalk <
cctalk at classiccmp.org> wrote:
noticed that
most pdp and vax gear just pull 120 volt legs off the 3 phase
to balance power loads. So you can run them on a couple of 120 circuits.
Outside of say the RP07 (which is a real 3 phase motor)
A number of the large disk drives use 3 phase motors; RP04/5/6 are
examples as well.
Three phase motors won't run on single phase power without help from run
capacitors. (There is no such thing as "two phase power" -- 220 volts is
single phase, balanced.)
If the issue is motors, a "variable frequency converter" will do the job
easily. I have suggested in the past that three phase power supplies could
run from those, but others have pointed out I overlooked some issues. So
that's probably not a good idea.
If you need three phase power to feed power supplies or other non-motor
power consumers, the best answer is probably a "rotary converter". You can
find those in machine tool supply catalogs. Basically they are a three
phase motor equipped with run capacitors so they can be fed single phase
power; the three phase power needed is then taken off the three motor
terminals. You can think of these as rotary transformers -- dynamotors in
a sense, for those of you who remember electronics that old. :-)
Don't look at "static converters" -- those are only for motors, it seems
they aren't much more than run capacitors in a box. They won't help you
for anything other than a motor, and even for motors they aren't very good.
paul
On Jul 13, 2021, at 11:34 PM, Chris Zach via
cctalk <
cctalk at classiccmp.org> wrote:
When we got an 8530 at work in the early 90s
(needed a machine with a
Nautilus bus for specific hardware testing), it was definitely a
3-phase machine and since we were in an industrial setting, I just
tapped into our panel at the back of the warehouse and wired up a
3-phase outlet for it. It never sat on our datacenter floor as a
result, but it really only ever had one purpose and that wasn't a
daily driver. Too much power, too much heat for so few employees (at
that stage of the company).
Interesting. Were the power supplies 3 phase input? Like you I have