Building a VFD for a split phase (capacitor run) motor?

Question

I'd like to get variable speed on a very tiny lathe (Taig, 4" swing). I've got a dishwasher motor I'm planning on using for it, which is rated for 3600rpm at 60Hz (it's about 1/5HP). But it's a capacitor-run motor (no centrifugal switch) and I think that means I have direct access to both windings. Any recommendations for building a VFD to drive this? I am fairly well versed in basic circuit analysis, just never designed much to deal with 110V.

I understand the general operating principle of a VFD, I'm just not sure how to make the low-voltage sinusoids I can easily generate control the 110V I'd get by putting a rectifier on mains voltage.

Alternatively, if there's a not-very-expensive commercial product I can use for this, I'd love to know. I don't want to spend more than about $70 on this project, because at some point it'll be cheaper to buy a brushless industrial sewing machine motor off Ebay.

Answer 1

There are VFDs for single phase Permanent Split Capacitor (PSC) induction motors, and if you say there is a capacitor but no centrifugal switch, then it must be a PSC type. These VFDs for single phase motors however will cost you a lot more than $70, probably 3 to 4x more, so you had better plan on using your other motor option.