>>>> "Rich" == Rich Alderson
<RichA at vulcan.com> writes:
Rich> Some here seem to think that we are amateurs--if not
Rich> idiots--working on a home system, and unaware of the
Rich> precautions necessary before making changes to the power system
Rich> of any large computer.
Perhaps "some" are merely unaware of the background of the person(s)
asking the questions. Yes, it's somewhat annoying to an expert to get
an answer that assumes he's a novice. But it's potentially much
nastier for a novice to get back an answer that assumes the knowledge
of an expert. Personally, I tend to write as if the audience is not
all that experienced (unless I specifically know otherwise, and even
then there will be others reading the archives later) -- in the hopes
that experts will simply skip over the "obvious" stuff without taking
offense.
Yes, an expert knows how to rewire electronics that uses 3-phase power
so it uses several 1-phase feeds instead. A novice might overlook
important details, such as the fact that the neutral in a 3-phase Y
system is smaller than the phase wires, which means you have to
substitute larger wires there for this rewire job.
And finally, if you have a system that actually has a 3-phase input to
the DC supply (for example, 6 diodes from 3 center-tapped windings
feeding the ripple filter), then rewiring that input as 3 separate
single phase circuits is not going to work quite right, because you
will then have inadequate filtering (having replaced 360 Hz ripple by
120 Hz ripple). It doesn't sound like this shows up in VAXen; I don't
know if it does in the KL-10; but I do know it is a consideration if
you're working on a CDC 6000 series machine because it has such supplies.
paul