Variable speed grinder questions/help


Well-Known Member
Currently I have a 2x72 of my own making and I would like to upgrade to a more rigid setup. I’ve found plans that I can tackle and am going from there.
My questions mostly revolve around the VFD. Can I use my current motor, single phase 2hp (1750 rpm) or will I need to invest in something else. Also any recommendations on a VFD that is crazy simple to wire? I’m electronically challenged to say the least.

Wayne Coe

Forum Owner - Moderator
If you use a VFD you will have to have a 3 phase motor. The KBAC 27D is the only VFD to get for a grinder. Expensive but the last and if you order my wiring kit it come with my one page instructions for wiring and setting up the motor and VFD.
Check out the pages on my web-site. On the Grinders page there is a video of the Moe's Grinder that you can build from the instructions on the DVD.

Let me know if I can help you.



Well-Known Member
Wayne is correct, to use a VFD drive it's best to use a 3 ph motor. While a VFD can be purchased for a 1ph motor, you'll spend more then purchasing a 3 ph motor. For a commercial operation where the grinder runs 8 hrs/day I'd sure go with the expensive KBAC VFD also. BUT - for a hobby person like myself the cheap Chinese VFD drives work very good. I've got 3 of them running now, and 1 Telco drive. The last couple I purchased were in the $70 to $80 range shipped, super easy to setup the program and seem to work just fine. These are NEMA 1 enclosures so do need to be mounted in a box, or as I do put a filter over the air inlets.

Good luck and have fun

Drew Riley

Well-Known Member
I have both a 2hp chinese VFD, and a KBAC-27d in my shop. The china VFD is actually a little bit more versatile than the KBAC, and at a 1/4 of the price, it's well worth the money and then some.

That said....

The KBAC is a really nice unit, especially if you don't have 220VAC in the shop, as it can run up to 1.5hp on 110VAC. Also, it's dust proof, and it's pretty much plug and play. If you've never programmed a digital VFD before, they can be a bit overwhelming, especially when trying to read the "chingrish" manuals.

At the end of the day, they'll both spin a motor though.

J. Hoffman

Dealer - Purveyor
3 phase motors can be easy/cheap to find. Nobody wants them. I paid $60 for my last 1.5 hp Leeson from the pawn shop and it was still in the shrink wrap. For VFD I wouldn't consider anything other than KBAC, but then again, my grinders are gold plated. KBAC`s can be found on sale pretty reasonable.