- Dec 19, 2019
Best option at $50-$80 depending on Amp rating. It will vary the speed very well.
Variable Fan Speed Controller link
This is a cheaper option for $18. Its used for fans, but it will work for any AC motor that draws no more than the rating 120v 15 amps. Works best on motors that draw closer to 15 amps because the slowest setting only goes down so far. It doesn't slow down my 3 amp bench grinder, but works well on my 7 amp angle grinder.