Thank you for responding. Of course the rest of us think they are clearly in phase.
Back on post 50... you were taking strong issue with a web page saying that the two hots of a center tapped distribution transformer were out of phase. You were wrong in saying they were in phase. Two signals being in phase or out of phase has nothing to do with what power company phase is powering the circuit.
Three phases, but that doesn't mean that an AC circuit phase cannot produce AC that can be in phase or our of phase. "In phase" or out of phase are just the most simple of phasing. Are the current and voltage on a power factor correction capacitor in phase? No. The current leads the voltage by about 90 degrees. But wait... that capacitor is hooked to a single phase. Yep. That is the way it works.
Yeah, about as hard as a plumbing supplier would laugh if you were to ask for a 10 gpm or a 60 PSI pipe. A house may be piped with a single water pipe, but that does not mean there cannot be different pressures in the house.
One half of the sine wave? I don't know what you are trying to describe with that term.
You were the one who started the battery analogy on this thread. Batteries have polarity. AC has phase. Yes, you can make an analogy, but it is only an analogy.
Two separate phases? No. Not separate. Two different voltages. Same frequency. Out of phase with each other-- which does not mean they are powered by a different phase of 3-phase power.
Those non-commoned battery terminals have opposite polarity with respect to our reference.
http://en.wikipedia.org/wiki/In_phase has some discussions of "in phase" etc.
If you only recognize "phase" as identifying which piece of a 3-phase and you cannot agree that the term "out of phase" or "in phase" can apply to voltages in a circuit powered by a single transformer, well, you are missing out.