On 08/08/2018 08:28 AM, trader_4 wrote:

According to Fretwell, two phase power existed 100 years ago, and it
was over two wires, 90 degrees phase difference.

Wouldn't that be 4 wires (2 per phase)

Yes, you're right and that's what he said and I acknowledged way back.
I just put two wires in the latest formulation of the questions that I posed
by mistake. The old 90 was two phase, 90 deg, on four wires. I used
that as a starting point because that's what Frewell says was a two
phase implementation.

When I first heard about that (90-deg 2-phase) he appeared to be saying
that since THAT was 2-plase, nothing ELSE could be.

So the
problem I posed is where I morph that into 240/120 service, one step
at a time. Looks like we're stuck on step one, Fretwell says if I
have those two windings that are 90 apart share a common neutral return,
it's no longer two phase, that two phase has to have 4 wires. Which
of course is bizarre. Why would two phases require 4 wires, when we
have 3 phase all over the place with with just 3?

I don't really know much about delta, but I do know what a phase is.

--
Mark Lloyd
http://notstupid.us/

"If a man would follow, today, the teachings of the Old Testament, he
would be a criminal. If he would follow strictly the teachings of the
New, he would be insane." -- Robert G. Ingersoll