20 Jan
2009
20 Jan
'09
1:58 p.m.
On 20 Jan 2009 at 15:53, Paul Koning wrote:
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.
Yup, but there the ripple frequency is 2400 Hz (at least on the CPU
supplies).
I used to show movies at a drive-in theater where the arcs were fed
from a 3-phase AC supply through a full-wave star
rectifier
configuration. Unlike the arcs that were fed from MG sets, these had
a very noticeable 360 Hz whine when operating.
Cheers,
Chuck