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Need Wiring Diagram for a 3-motor machine

allamateur

Plastic
Joined
Dec 27, 2020
I've got a Cinci Toolmaster 1-A with 2 feed motors and spindle motor, all 3-phase. I've gotten preliminary suggestions on wiring this up with 2 VFDs (both Teco L510, one 3 HP [for the 1HP spindle, oversized but it was cheap], and the one for feeds, each 1/4HP, is 1 HP) from the nice guys at hobby-machinist, but these suggestions don't involve any auxiliaries (like fuses, diodes, etc.) and I've finally gotten a big electrical box for all this stuff.

So basically I'm asking what are all the auxiliaries (and how to wire them) for a setup where the 1HP VFD powers both feeds at 60 Hz all the time, while the 3HP VFD powers the spindle at varying frequencies for speed control. I will admit that I originally had one of the banned eBay VFDs powering the feeds, but it would throw an over-current error when I had it wired in parallel with the spindle VFD and tried to use both at the same time. These are both in parallel from the same NEMA 10-30 dryer plug. I finally grounded everything properly (to neutral because 3-wire), tried it again, and the cheapo VFD popped like a balloon and took the original Teco with it. Before this, I was getting voltage readings in midair off the cheapo VFD. I'm not entirely sure what this means, but I imagine it means it was interfering with the spindle VFD and I need diodes or something to prevent feedback between the two VFDs. Other info: the two feed motors are wired in series to the 1HP VFD. These set-ups work individually (the feeds work if the spindle's off, and the spindle works if the feeds are off). I replaced both VFDs and now need some confirmation before I try again and waste more money popping VFDs.

Also apologies if this has been asked before, I couldn't find anything.
 

memphisjed

Stainless
Joined
Jan 21, 2019
Location
Memphis
220 3 wire, do not treat any wire as neutral. Leg A, Leg B, Ground. Yes you can split to get 110, but this is weighting odds for gremlins. If you want 110 at machine, run another 110 chord.
You can get din or panel mount 2 pole breakers cheap. Run one before each vfd.
No connecting high voltage wires between vfds.
Do you have anything connected to the dc bus outs? <- do not ask how I think you might....
 

allamateur

Plastic
Joined
Dec 27, 2020
Thanks for the reply. I haven't split the 220 hot legs from each other at all, just split all 3 wires from the 220V input to each VFD. Nothing on the low voltage DC buses either, though I think I will have to get a computer fan for the electrical box since the 1HP Teco doesn't seem to have its own fan. That could be powered by either VFD's low voltage DC bus I guess. There's a youtuber named Clough42 with a video on how he wired a similar fan for his lathe's Teco VFD, so I might just use that as instruction.
I'm going to find the right breakers for each VFD, thanks. Would this replace the "fast-acting fuses" (Bussman 50FE for 3HP VFD / 20CT for 1HP VFD) that Teco recommends? Part of the reason I made the thread was that the recommendations from Teco seem incomplete for my situation of having 2 VFDs in parallel..

Attached is a bad picture of the current situation. I didn't include the amperage draw from each motor but if I remember correctly, the draw for each half of the circuit is less than half of each VFD's output.
 

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