Unfortunately. Maybe we should more generic terminology to
describe this. There is a difference in the phase of the two
legs off of a center tapped transformer. This can not be
argued. Anyone who argues so can go hook up a couple scopes for
themselves as you suggested.

Maybe the confusion exsists because of the nature of two
seperate phase (split phase) power vs 3. Correct me if I am
wrong, but any device requiring 240V could be powered by 2 legs
of a center tapped 7200V==120V N 120V transformer or could be
powered by a 7200V==240V transformer with the same results.

That said Im sure someone will tell me why my theory of why
this is a confusion is wrong..

- Mike

|Hmm.. I must have not drank my coffee yet when I wrote this.. 3
phase would
|operate the same way therefore making this all bunk.

Actually three phase service from the power company with the
phases 120 degrees apart, would work differently. In a 'Y'
connection if the voltage between the phases were X volts, the
voltage from one phase to neutral would be x/sqrt(3) rather than
x/2 as is the case with a center tapped transformer.

David