Ya know I been thinking about evils hypothesis that it's already three phase ac because there are three winding each 90degrees apart. And yes the wave nature of the alternating current of represented graphically will show the summation of three sine waves each 90 degrees staggered.
That's a fact.
Now evil all three of those done waves have a chance to go below the horizontal if you capture both ends of the wires. So one wire ac on a trail tech which has three windings each 90 degrees apart gives energy from the x axis up. Two wire feeds you for dinner above and below the x axis. And I am hungry for electrons. Fools like me call that floating. Call it whatever you want.