On Jul 13, 1:04*pm, mm wrote:
On Sat, 10 Jul 2010 23:18:19 -0400, "Ed Pawlowski"

wrote:

"Jon Danniken" wrote

It is a function of the motor, which will be a split-phase induction
motor. You either have a motor designed with multiple windings for
multiple speeds, or you don't. *If you don't, the only practical way would
be to replace the motor with one designed with multiple windings, or get a
new unit.

Not quite true. *Mine works with a simple dimmer switch of proper capacity.
Multiple windings not needed.

It's said that motors won't run off of light dimmers, but of the 6 or
so table fans I've used over the years, all but one worked fine. *The
other one required a fan speed control, usually used for ceiling fans.
I got one at a surplus store.

*Induction* motors won't run off light dimmers. Universal motors will
(off dimmers rated for inductive loads). Small motors are almost
always universal motors. Whole house fans are likely a mix, with the
better ones being induction motors. Generally a belt is the tell
(belt = induction motor). I would guess the crossover is about
1/4HP.

I wouldnt' let the fan get so slow it stopped, althoughif the dimmer
is at the very bottom when this happens, maybe it's okay.. * Depending
on the fan, it might well overheat if it did that, and burn out the
fuse (or worse?). *Also if a whole house fan gets too slow, it won't
open the louvers I think, which are just sucked open.