Ralph,
You learnt right, but it's not a motor power thing, but rather a circuit capacity deal. I run my 22/44 Pro on a 20 amp 115 circuit. If the drum bogs more than a little, it'll trip that 20amp breaker very easily, sometimes before I can hit the drum kill-switch. If I were running 220 on a 20 amp breaker, I'd have more of a margin for available power draw. Yes, I could change out the 20 amp 115 breaker for a 30, but I don't want the machine to be able to draw that much amperage from the shop sub-panel.
M