Electrical question-lathe lighting

[Isaac Fisher]

I’m adding two Moffatt lamps with LED bulbs onto my PM 3520B lathe and wondering about powering them. I move the lathe at least once a month for club meetings and would like to minimize the number or cords running on the floor.

Option 1 is obvious and simple. Plug them into the 120v receptacles on the wall at my workstation and use an extension cord for the meetings.

Option 2 is to add a junction box with two 240v receptacles on the back of the lathe between the wall plug and the VFD. I could then run the lamps on 240v power, which I believe they’re able to handle.

Option 3 is to add a similarly-placed junction box, but using 120v receptacles. I’ll be upgrading the shop electrical panel next week, and adding a new lathe circuit with 4 conductors isn’t an issue.

Doing the work for any of the options is pretty straightforward and well within my abilities. What I’m uncertain about is possible negative effects on the VFD and the LED bulbs from options 2 or 3.

Any electrical engineers hanging around who could offer some guidance?

Thanks,
Isaac

 

[Dave Landers]

If your lights are ok with 240v, and given that you are moving the lathe around, I'd opt for #2 as it reduces the extension cords and is fairly simple.

If the lamps need 120, then what I've done in the past is add a 20A 240v, split-phase circuit and wire a 240v outlet across black/red, and a couple 120v outlets across the black/white and red/white. I ran my 3520b like that for years with lights, sander, etc plugged into the 120. Problem with this arrangement is that if you move the lathe, the right outlet/circuit is harder to come by.

 

[Kurt Manley]

Not an electrical engineer by any means, not even close but what I would do is put a four gang box with 4 120 outlets on the lathe and just run a separate cord out of it to a 110 outlet but wrap it with the lathe cord so it's essentially one cord. Then I'd wire a 110 and 220 outlet right next to each other when you redo the shop wiring.
If I am reading your post right it seems like you are talking about pulling power from inside the lathe itself for your outlets? I could be wrong...But even if that works for the lights what if you at some point want a sander or grinder, or something with even higher draw? If it was wired separately you'd never have the possibility of overloading anything within the lathe.

 

[Isaac Fisher]

Dave, thanks for the confirmation that the split circuit has worked for you. When I move the lathe it’s always to the same spot, so adding another appropriate circuit there will solve the special plug issue. Both aread are less than 20 feet from the panel, so it won’t be too difficult or expensive.

Kurt, no matter what I end up doing, the lathe and any other loads attached to it will have 30 amps available. If I need to run anything bigger than that I’ve got 120v outlets every four feet on a separate 20 amp circuit.

Right now I’ve got everything plugged in separately, but I’m pathologically tidy, especially about things like cords and hoses.

 

[Wally Crawford]

I ran one of these https://www.harborfreight.com/5-out...tal-housing-and-2-usb-ports-orange-57250.html to my Robust AB and it allows mw to plug in several lights and a sander.

 

[Bob Hall]

I went with #2 also but I have an older 110v lathe. It is nice and convenient for my uses for now.

Bob

 

[Hugh]

Put a couple of outlets at the correct voltage in the ceiling. Actually, put in two sets as you move the lathe. No extension cords on the floor.
While you are at it, put a 220V outlet in the ceiling for the lathe also.....maybe two of them for when you move the lathe.
I did that in my shop when it was being built. Love it. No cords from the wall to the lathe or lights.

 

[Dave Landers]

Put a couple of outlets at the correct voltage in the ceiling. Actually, put in two sets as you move the lathe. No extension cords on the floor.
While you are at it, put a 220V outlet in the ceiling for the lathe also.....maybe two of them for when you move the lathe.
I did that in my shop when it was being built. Love it. No cords from the wall to the lathe or lights.

Yep. When I was using the 240v split phase with 120 outlets I had a twist-lock in the ceiling so the power ran down one cord just behind the headstock.
I built a new shop last year, so I have plenty of outlets where I needed them. So I'm not wired like that anymore - but it worked well in the old place.

 

[Don Wattenhofer]

Option 2 is to add a junction box with two 240v receptacles on the back of the lathe between the wall plug and the VFD. I could then run the lamps on 240v power, which I believe they’re able to handle.

Change the 230 volt cord to a 4 wire - red, black, white and green then the red & black wires will supply the 230 volt to the VFD and red - white & black white will make up 2 115 volt circuits and the green wire is the ground for everything. Note a 3HP 3 phase motor will draw about 10 amps and the minimum circuit size is 20 amp at 80% loading would provide 16 amps so your sander or whatever should not overload the circuit.
The biggest problem with this idea is that there may not be a white ( circuit neutral) wire in the outlet box but the circuit should be wired with a 3 wire (black, red, white plus the bare wire for ground.

 

[Isaac Fisher]

Thanks, everyone. I’m going with the third option. running two new 30 A 10/3 circuits and splitting off 120v receptacles from . I’ve done this before with other machines, but those were all single-phase. I have wired up several VFD’s, but I have no idea what happens inside or how sensitive they are to slight load imbalances between the two legs. I don’t hear anyone saying that this setup has caused problems in the real world, so I’m going for it!