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Simple Way to Hook Up a VFD to a 13x40 Lathe

So Jerimy reached out to me last week for help with his Enco 13x40 lathe which is different from mine.  His was designed with 3-phase input, and he wanted to be able to use it with the lathe controls and the VFD.  But he had a problem; the VFD can't make 3-phase input power to the lathe, because the VFD output power should never be switched. I spent a few hours trying to track down his lathe wiring diagram, and make sense of the thorough wiring diagram he had traced out from his control box.  I found several possible candidates for the diagram, and was going back and forth with Jerimy to see if we could figure out how to make it work.  Then it finally occurred to me that it's really easy to hook up a VFD to most ENCO lathes (and probably many other Taiwanese/Chinese lathes.  Here's the easy scoop. 1) You need to make sure that you run main power to the control box.  If you have a single-phase lathe, that's easy -- just use the two conductors on the line...

Adding a VFD to my Enco 13x40 lathe

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I decided to take the plunge and add a VFD to my Enco 13x40 lathe.  The main reason I chose to do so was because there is chatter when I cut threads, which has been attributed to the use of a 2-pole single-phase AC motor on the lath. So I have switched to a 4-pole, 3-phase AC motor.  I hope it will work out OK.  The maximum speed is higher, so I'm a bit concerned about that.  But I can reduce the speed with my VFD, and I can choose an appropriate gear range.  So I think it will be fine. I had to make a spindle adapter to adapt my new motor to the old pulley.  I may choose to detail that more in the future, but I didn't take any pictures while it was apart, so I'll not tell that part of the story for now. My plan is to have everything work through the standard lathe controls, rather than running everything through the VFD panel controls.   I intend to use a potentiometer to control the speed, rather than using the up and down arrows o...