wrote in message
...
On Tue, 30 Jan 2018 10:24:36 -0800 (PST), "Dave, I can't do that"
wrote:

Hi All,

Subject says it all. We have a 110vac, 1/3hp, 2-speed motor on the
swamp.

https://www.homedepot.com/p/2-Speed-...2204/100013540

I would like to have variable speed. Are there any kinds of
controllers that will do this without changing motors?

The Low speed is not low enough so I a looking to just use the High
speed wire to the motor and spread control over the entire rpm
range.

I am looking for a low cost thing. Kinda like a ceiling fan control
that handles a 1/2hp motor. I say "1/2hp" for a little wiggle room
if I have to change motors at some time in the future.

Possible?

Thanks
If your motor has a switched start winding then you cannot run it a
lower speed. The start winding is disconnected from the power when
the
motor reaches about 85% of the rated lowest speed. From the link
provided it looks like the motor has a switched start winding. Turn
off the motor while listening to it and if you hear a click and/or a
whirring sound then that is the switching being heard. The motor
will
overheat rapidly if run too slow. For two reasons. First, the start
winding is not made to be energized for more than the time it takes
to
start the motor. It heats up rapidly. Second, the motor will draw
more
current as the voltage drops in an attempt to get back up to speed.
This extra current draw will cause the windings to run very hot
until
they let out the magic smoke.
Eric

http://www.electricaleasy.com/2014/0...ion-motor.html
Notice the lack of cheap, simple ways. The real answer is to change
the motor to a more easily controlled type.

The higher wire resistance that makes the start winding quickly
overheat is there for good engineering reasons, not just to cut the
cost or frustrate you.