"John Larkin" wrote in
message ...
Wow. If it was delta, then 110 3-phase would require 6 wires (or five
if you cheat and share one corner) so the 110 3-phase motor would need
three isolated windings and most likely a 6-pole on/off switch. Was it
really like that?

Nope. Draw a picture of a Delta, center-tap each winding, and the three
center taps form another delta at half the voltage. Used a perfectly
standard (for 1922) 3 phase, 3 wire, 110v, 25Hz motor.

The 110 volt service made no connection to the corners of the 220 delta. The
110 delta was fed only from the center taps.