OK, I've got George's CD, but I have not found the ST head wiring section. Help me understand how the 120/240 wire happens.
My original thought was each 120V winding, was out of phase with the other one, and you could use off either phase till you reached max load per phase. This is what load balancing is about. If you have 1 high current device that only comes on once in a while, you have to have it on it's own winding, and throw everything else onto the other winding. This leaves one winding carrying half the load, nearly all the time, and the other winding idles 90% of the time.
I also thought if wired for 240, both windings would be in use, out of phase, and a 240:120 step down transformer could be used to supply loads as needed, and 240 would be avaib all the time. This would split the entire load, evenly over all the windings, and the transformer (easily replaceable if fried) would both equalize loads for 120, and the mass of iron and copper would "even up" the waveform to something closer to pure sine.