**You would, of course, be wrong. It is a widely used practice, for slowing
FANS using shaded pole motors down to lower speeds. You seem to be
forgetting that although fans use sychronous motors, they are under
constant, heavy load. As such, they can never reach the theoretical
synchronous speed, which is determined by the number of poles and the
frequency of operation. As such, use of a resistor (or even a cap) is a most
effective form of speed control.

And again, I refer you to the original poster's requirement that the speed
control be SIMPLE.


Oh, people always ask "What's the easiest way of....". :-)
Sometimes you have to give them the right answer, not the quick fix.