Running a 1-phase 240V welder off 3-phase 240V power receptacle?

[jakeru]

I have an Everlast Super200P. It uses 1-phase 240V input power. (2 live 240VAC conductors, and one equipment grounding conductor.)

I was wondering if anyone knows if I can wire an adapter to operate this welding machine off of a 3-phase 240V receptacle?

The 3-phase receptacle I would like to run my welder off of is a NEMA-L15-20R

(pic from: http://www.powerfig.com/nema-locking-chart.aspx )

I only need to TIG weld some .040" stainless using this. (Probably won't be drawing a large amount of current.)

Thanks!

[Ray]

Are you sure it's 240V, 240-3 is rare, it's more likely 208 or 220.
I sent you a PM.

[Steveg]

Why not. Just use any two of the hot wires and the ground wire, ignore the other hot wire. Three phase can be either 208 or 240 or some other voltage depending on how you tap the transformer.

sg

[jakeru]

I haven't taken any voltage readings off the receptacle, but next time I am at the work site, (if I do move forward with this job, anyway), I will do so.

The face of the NEMA plug/receptacle has "250V" embossed on it, but I could see that being a "max allowable" and not necessary indicate the typical voltage. But I'm kind of hoping/anticipating it would be 230-240V.

Based on some old welding machine specs I found I had printed out, I wonder if my machine might even be able to handle 208V if that's what I find?
"AC220 +/- 15% 50/60Hz"
I am not 100% certain these are the right specs for this machine (Everlast Super200P) or not. But if so, it would seem to mean the machine could run off a fairly wide, 187V-253V operating range.

[performance]

Actually Ray,
240 is not rare in 3 phase. It is very common in my neck of the woods. 208 is almost non existent, and found in many "older" installations.

Jake to determine the type of 3 phase you have, you need to measure leg to leg and then measure leg to ground.

240 Delta has a "wild" leg that will measure approx 220-240 across the leg but measure something like 277 to ground while the other legs measure 115 or so to ground.

You need to use the 2 legs that measure 115 volts to ground for leg to leg, Not a 115 and 277 leg even though they measure 220 across the terminals.

[Ray]

Thanks Mark, mostly 208 here from what I’ve seen.
Jake the markings on the outlet are the NEMA Ratings only. Really has no bearing on what’s actually there other than the installers willingness to follow code. Check it. You’d be amazed at what I’ve found/seen.

[jakeru]

Thanks for the tips guys. It sounds like I can work off of this receptacle then, provided that the voltage is in an acceptable range, and I don't overload the circuit.

Also, thanks Mark about the tip about testing for and avoiding using the "wild" leg, if I do find one. If all three legs have equal voltage to ground, I guess it would mean the circuit is driven by the other ("Wye/Star"?) type of 3-phase transformer.

I already mentioned to Ray that there was some type of free-standing, industrial dough mixing machine plugged into this receptacle. Kind of like a KitchenAid on steroids.

[Rivets]

Hey Jakeru,

Did you succeed in hooking up your unit to one of the 240 volt phases ?
How did it work out for you ?

Cheers,
Rivets

[performance]

High leg....Bastard Leg...Wild Leg...I have heard several terms for this.

[everlastsupport]

Ken,

Thanks for a great answer and a proper solution. No ground IS a major safety issue.

I still would think there is 110volts somewhere in the place that will lead back to a 110/220 panel.

[Ole Sarge]

Agree, single phase xfmr is a proper idea, trying to make single phase 240 off of a delta or Y is asking for an exciting life, perhaps even a short one.

Actually, ground won't but their will be flow on the neutral which attaches to the same point as the ground, but ground, as you say, should never be used as a current carry conductor, only for fault current.