12 Dec
2012
12 Dec
'12
12:20 p.m.
It's been more than 25 years, so my recollection may be hazy, but I
think we had 208V 3-phase. I don't recall if it was delta or wye
configured, but I tend to think it was the former. CPU from one phase,
disk and tape drives from the other and our two big CDC line printers
from the third. But as I said, it's been over 25 years since the
electricians installed the stuff. We just went by what they recommended.
Chuck
Yes, our 780 was 208V 3Phase, and I'm PRETTY sure it was 5-wire,
so it had a neutral and a ground pin. I think some of the outlets
are still in the wall at work, so I'll check the twist-lock to
see. I think the power supplies could run off 240 V as well,
but possibly the whole machine was slightly different for that
option. I know our big data center with IBM 370s was all
208 V also.
The multiple H7800 (I think) power supplies each ran off a single
phase bridged between two hots, but they were distributed around the
phases. The LSI-11 and maybe a few other things ran off 120 V,
and I think there was a scope/etc. 120 V outlet there, too.
The big cooling blowers were each across two different phases.
Some of the larger disk drives had 3-phase motors, and the high-end
tape drives (TU-76, TU-77) had 3-phase power supplies and vacuum
blower motors.
I think the Vax 11/750 was single-phase 220 V, and the 730 was
120 V.
Jon