Running 3 phase 780s on single phase power
Gordon JC Pearce MM3YEQ
gordonjcp at gjcp.net
Wed Jan 21 06:21:04 CST 2009
On Tue, 2009-01-20 at 13:06 -0800, Guy Sotomayor wrote:
> On Jan 20, 2009, at 12:35 PM, Rich Alderson wrote:
> > The KL-10, like other DEC gear, uses 3-phase input power as the
> > simplest
> > way to get lots of amps into the system: 60A @ 208 3-phase. All of
> > this feeds into a single gigantic boat-anchor grade transformer which
> > forms the basis of a linear power supply. 2/3 of that power goes back
> > out as simple heat.
> Umm. No. That transformer is a ferro-resonant transformer. It
> *needs* 3-phase to work! It supplies the basic 12v DC that are then
> used to by the linear regulators. It's those that burn the power as
> heat. Replacing the linear regulators with switchers will reduce the
> consumed power by a lot.
Since extremely high current switchers are relatively cheap (at least
compared to getting three-phase installed, and massive aircon systems),
is there any reason why you *wouldn't* go down this route? Particularly
for a machine that's going to be on a lot?
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