I'm back on it. I've gotten pretty far with figuring out this project, but I'm stymied at this point. I thought I had it all figured out last night, but the harsh light of day shattered everything.
Here's the lathe I'm hacking:
Nice, solidly built frame, halfway decent bearings in the spindle, reeves drive. We all know the problem: lowest speed is too fast. Only solution: VFD and a new, 3 phase motor. I'd like to stay at 2 HP, since most of the better lathes are 1.5 to 2 HP. Based on the VFDs I've found, that pretty much means I need to run 220 into the shop, which I guess I should do anyway. The 110 VFDs pretty much top out at 1 HP. So...
220 to the shop (it's really only a 20 foot run from the main panel in the basement, and I've already got a now unused 220 breaker on the main that used to power the oven). Subpanel in the shop, with both 110 and 220 coming out of it. Here's the VFD I'm thinking will do the job:
single phase in, 3 phase out. I'm not real clear on how to hook it up, but I can probably figure it out. I figure I can route around the switch on the lathe. Not real clear on how to set speed controls on it, but again, I can probably figure that out. It's $145, so that's inside the budget.
OK, on to the motor. I want to keep the reeves drive... and doing that uncomplicates part of the project. That means I only need to worry about the motor spindle size, which I take it is not universal or standardized. But I can measure the shaft on the existing motor. The real problem:
As far as I can tell, I need a motor that is
about 1700 rpm
and probably a bunch of other variables that I have no idea about. I found this motor last night:
for 70 bucks, and got very excited. That's a price within reach. it's not tefc. It's not inverter duty (whatever that actually means). And I don't know the spindle would match. So, I go searching for a motor that I think might match my percieved specs, and can't find anything for less than many hundreds of dollars. Am I barking up the wrong tree? How does one go about finding a motor like that for under a hundred bucks? This all started because people said I could pick up a 3 phase motor cheap. HELP!