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3 phase welder from split phase, or single phase 3 wire 480v supply

robertlaurenson

Plastic
Joined
Jun 27, 2020
Location
Shetland
Hello all.
I have a split phase / Bi Phase, single phase 3 wire (USA style system), 2 phases coming into the workshop from a center tapped transformer. 240v phase to neutral and 480 phase to phase.
I have been looking at 3 phase welders and specifically the inverter ones, for instance miller in the USA do welders which can run on 230, 460, 570v single phase with the 460v being the same system i have installed.
I now need to get a large Mig welder to complete my workshop, most of them as soon as you go over 250A they have to be 3 phase.
My question is relating to the inverter type welders on the market, i am not sure if what i am going to ask is even remotely possible but with my minimal knowledge on these welders and what i can find on the internet it seems like it may be possible.
My question is as follows, can i take the 2 legs i have with 480v between them, say put them in L1 and L2 of the welder and then put a series of links in between L1, L2 and L3 to in effect make the machine think i am powering it from 3 phase. i.e it will see power across all phases. the only thing with this is the phases wouldn't be balanced 120 degrees apart but i am not sure the machine would be this "clever" and would more be looking for a voltage across each leg.
In my simple understanding of the way these inverters work they take in a "3 phase" supply and convert it to DC and output it through a second inverter in the machine.
Any help on this would be greatly appreciated. It is a big outlay to buy a 3 phase welder of this size and not much point doing it if this wont work. My other possible options are a Rotary converter, or a Drives Direct digital one.
Thanks in advance
Robert
 
Miller inverter power sources for example the XMT series will operate on both single and three phase.
The XMT series will provide 350 amps with a single phase input. not until the XMT 450do you need three phase and yes it will not work on single phase.
So here's the deal Miller, Lincoln,build inverters that are built for both single and three phase input.
However if it's built/shipped as a three phase power source then it's a three phase input power.
Some people alter the internals to semi mimic a three phase input on single phase input, there's information on line related to how to do this. However if the power source is under any type of warranty this would be the fastest way to void that warranty.
Additionally if you need the output of as you describe a larger three phase inverter power source you would be wise not to go down this road.
Hope this helps.
 
Miller inverter power sources for example the XMT series will operate on both single and three phase.
The XMT series will provide 350 amps with a single phase input. not until the XMT 450do you need three phase and yes it will not work on single phase.
So here's the deal Miller, Lincoln,build inverters that are built for both single and three phase input.
However if it's built/shipped as a three phase power source then it's a three phase input power.
Some people alter the internals to semi mimic a three phase input on single phase input, there's information on line related to how to do this. However if the power source is under any type of warranty this would be the fastest way to void that warranty.
Additionally if you need the output of as you describe a larger three phase inverter power source you would be wise not to go down this road.
Hope this helps.

Thanks for the information.
I have looked at the XMT350 Mpa one,
I have actually found a couple of others which are capable of running also.
The Lincoln - Powerwave 350s
and another which is made in the UK
The Oxford S-Mig 410s Double Pulse
Are the Oxfords good machines? see a lot on the internet about them and folk saying they are great but cant find much on the double pulse versions.
Thanks
 
We use both Miller and Lincoln, constant voltage as well as constant current transformer based power sources, great machines that will go the distance, basically run forever. That said we also have both Miller and Lincoln inverter based power sources, they weld great and can in many case's be tailored to fine tune the arc better then the transformer based power sources.
Personally I like both Miller and Lincoln, the pulse control is great.
Now the bad news , inverters will never have the life expectancy of a transformer. Does miller out live Lincoln I can't say.
What I can say is we have a fair collection of dead inverters Both brands.
I am not slamming the door on inverters, we use them and some are over 12 years old and going strong, others a couple years out of the warranty period and they take out a mother board or some other high dollar component, generally exceeding the value of the power source.
I did e-mail a buddy in the U.K. that I know use's Oxford constant voltage power sources and he's happy with them and that they been reliable. For what it's worth.
 
My welder is a three phase SCR controlled "inverter" and it's 26 years old. I replaced the catalytic capacitors in it and it still runs fine. That's why I prefer the old welders, they last.

Modern inverters got all kinds of goodies but I doubt one will last 26 years, or longer.

With three phase you can get a really nice arc without the need of advanced switching.
 
I have a Lincoln Invertec V350 and a Miller Maxtron 450, both of which will run full power from single phase.

I do wonder about the longevity of inverters (I doubt any will ever touch my 50 year old Miller 450A stick welder), but my inverter is the Red-D-Arc model, meaning it was a rental, and is still going strong.
 
Count your blessings on the rental unit, Here in the United states all the large welding rental sources generally have a life cycle for inverter based power sources, most of the time it's the period of factory warrantee. Then dump before the real problems start. I personally know one very large contractor that rents inverters for Carbon arc gouging on heavy beams because they don't want to beat the crap out of there own power sources.
 
Count your blessings on the rental unit, Here in the United states all the large welding rental sources generally have a life cycle for inverter based power sources, most of the time it's the period of factory warrantee. Then dump before the real problems start. I personally know one very large contractor that rents inverters for Carbon arc gouging on heavy beams because they don't want to beat the crap out of there own power sources.

Yep, I do. I knew it was a big gamble, but the auction price made the chance worth taking. I figure if it survived this far, it's relatively gentle life from here forward, hopefully, will be long.
 








 
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