Tony Miklos wrote:

Sorry antagonist. That is incorrect. The "phases" as you describe, are
still in sync with each other. Their voltage potential from
neutral/center tap is indeed *opposite*, but still "in phase".


But using this definition of "in phase", all power systems are "in
phase" as the respective phase angles are constant between all phases.
It doesn't matter if the phase separation is 90, 120 or 180 (as in split
phase). The reality is that you can't distinquish "split" phase from
"two" phase with 180 degree phase separation, as they are identical. It
doesn't matter if the two phases are created directly from a rotating
machine or from a center tapped transformer.

Matt