3-phase power

Noel Chiappa jnc at mercury.lcs.mit.edu
Tue Jan 4 17:39:53 CST 2022

    > From: Jon Elson

    > It should be 208V

Oh, right you are. It's been a long time, and I had a distinct memory that it
was less than that, but I looked, and I think that's it. The term for my
flavour of 3-phase is apparently "open wye/open delta"; each leg is 240V to
the others, but only two are 110V to neutral - the "hi leg" (normally
colour-coded orange; normal 3-phase uses black/red/blue) is 208V.

The page Jonathan Chapman sent had a good diagram of how it is wired:


When they were doing some work on the pole decades back, I asked the foreman
how it worked, and he drew a diagram to show me; I had forgotten it, but
seeing that, that is it. The A and C are produced off one feed phase, but the
B comes from the second feed phase.


More information about the cctech mailing list