In article . com,
hylourgos wrote:
I ran across this dual-speed motor, but there doesn't seem to be any
room for drives in order effect the speed change. How do they do it on
this model?

H


you can design a motor with a switchable number of poles. it will run
at different speeds, depending which sets of coils, etc. are hooked up
to the power at any given time.

Multi-speed motors for GFA furnaces are one of the more common examples.