20 Jul
2016
20 Jul
'16
5:59 a.m.
On Jul 19, 2016, at 4:55 PM, Greg Stark <stark at
mit.edu> wrote:
On Tue, Jul 19, 2016 at 5:47 PM, Mouse <mouse at rodents-montreal.org> wrote:
Three phase power shows up in a bunch of places. Some high current power supplies (pre
switching era) use three phase input to increase the ripple frequency and reduce its
amplitude, which significantly reduces the size of the required filter capacitors. I
remember that in the KL-10. CDC 6000 mainframes go further, not only using 3 phase but
also 400 Hz power for that reason (that also shrinks the transformers).
Cooling systems might run on 3 phase, or not. The compressors in the 6000 series CPU
cabinets are 3 phase motors. But the DD60 display uses 3 phase power only for the high
voltage power supplies; the cooling fans are run off 230 V 60 Hz single phase.
If I remember right, the RP04 uses 3 phase power for the spindle motor. Probably not for
the logic power, though.
paul
For example, I once had a neighbour who replaced
an outlet in his
kitchen. Turned off the breaker, removed the old one, put in the new
one, all very nice. Turned the breaker for that circuit back on and
popped the service main breaker.
Heh, I knew what was coming here and that it must mean you were in
Canada (and only then checked the sender...)
But all this seems like a red herring. Surely the three-phase power
requiring devices only require three phase for the cooling systems?
Wouldn't it be easier to just use a modern switching power supply to
provide 5V and feed cold air directly from your home hvac and not try
to run 50-year old cooling and power?