Certainly not the right solution and it may not work, but worth trying as an experiment with very long ramp up speeds since lathes have lots of inertia.
I don't know anything about VFDs other than they can be complicated in the sense of offering a billion options in terms of programming. Which is good actually. Although I don't know how to program one yet.
You didn’t say what VFD you have.
I don't yet own a VFD. I'm looking at one on eBay for $89. It's 1.5 Kw I take it that's equivalent to 2 HP.
If it fails, it will most likely fault out. Nothing should fry/die. If it does, then you’re better off, as you have eliminated a really crappy VFD
Falling out would be no problem. But obviously a total fry would instantly destroy $89. If it doesn't fry I could either recoup the money later by reselling it, or possibly use it for an actual 2 HP 3 PH motor in the future.
Here's the LONG STORY:
I just purchased a Warner & Swasey No. 3 lathe at basically scrap metal price. This way if it turns out to be scrap metal I haven't lost much.
The lathe appears to be in fair condition actually. It also appears to be complete although without any tooling.
Short Term Plans:
I would like to get the lathe up and running, at least enough to make it go through all its motions so I can check to see what works, and what might need to be repaired in terms of automatic feeds, and other functions.
I'm torn between two options.
Option 1: Try to fire it up on a cheap VFD as per the topic of this post.
Option 2: Replace the original 3PH 5 HP motor with a single phase 1 HP motor, just for this initial run and inspection of what works and what doesn't.
Long Term Plans:
If the lathe proves to be in fair shape and usable I plan to eventually build a homemade Rotary phase converter for it. In the meantime I can actually work on restoring and/or repairing anything on the lathe that needs attention.
More Information:
I love restoring old machines. The ultimate long term plan is to potentially buy more machines to clean up and restore. I'd love to have a milling machine and a surface grinder too. So building the 3PH Rotary converter will be well worth it as I could then use it to power other machines in the future.
In the meantime, for right now, I'd just like to get this lathe "turning" if you'll pardon the pun. I'd like to be able to see what kind of running condition it might be in so I can decide whether to go forward with a full restoration, or part it out and scrap what's left. In any event, this won't be the last machine I buy. But hopefully it will turn out to be a good one, at least for the price which was pretty much rock bottom. Any less and it would have been below scrap metal prices.
Final Note:
I'm actually more interested in rebuilding old lathes and milling machines than in actually using them. Although I'm sure I will use them once I get them up and running.
In any case, the current goal right now it just to get this thing turning. I've even thought about running it will a small garden tractor engine in a pinch.
I just want to make it go for now to see if it even works at all. The main goal right now it to just check the functionality of the machine. I'll come up with a better power supply solution later once the machine is ready to actually use. The $89 VFD seems like a quick and dirty solution if it works! Of course, if it fries itself then it's $89 down the toilet. If it just doesn't work but doesn't hurt itself, then I can either continue to use it for smaller motors, or resell it and recoup some of the money I paid for it.
