Jerry wrote:The accepted definition for two phase power is two legs (poles) 90 degrees out of phase with each other.
Yup, I agree with you that this is the accepted definition. Still, it
is two lines of what would be a four phase system if all the phases were provided for.
One to 'two phase' conversion [as in not what is called two phase, but what is 'two phase'] is very simple as a second, mirrored, phase can be accomplished with a second winding that provides the phase in the opposite sense, at 180 degree. There is a difference between the
accepted definition of two phase, and what is what you might describe as 'theoretically two phase' (the latter being 180 degree separation, because 360/2 = 180!!].