Running a 3ph mig on an RPC

I traded for a minty Airco PhaseArc 350 mig welder last week with the idea of maybe either being able to run it from a 5hp rotary phase converter that I run my machine tools in my hobby shop with, or selling it and purchasing a single phase machine.

Yesterday morning, I wired it up, using a 12/3 100' extension cord. I figured I might as well try it worst case. (yes, I know..no safety ground..shrug)

To make a long story short, it worked beautifuly. I spent about 5 minutes doing nothing but filling the top of a chunk of plate with a

6" continious back and forth bead of .035 wire, thinking that something should get warm, or reach welding time % and it just kept feeding and burning with that marvelous frying bacon sound, with good puddle and penetration. I sectioned a chunk of the plate with an abrasive saw and penetration was very good.

I then loaded a spool of .045 dual shield and did the same thing. It took a fair amount more volts of course, and every thing worked fine. I do have an issue with the Arcomatic lV wire feeder with the bigger wire, as its not the proper feed roller for that size I dont think..but all in all it burned well. The .035 burned best with the meter settings at 21-22 volts and the welding output amp meter showed around 100-125 amps during welding. Today Ill put a amp meter on the line and see what the actual draw on the RPC is Everything remained nice and cool, even the horrendously long and undersized extension cord remained cool.

A Rotary Phase converter is easy to build, lots of plans on the net, and they can be built quite cheaply.

So picking up a decent commercial 3ph mig welder cheaply (since lots of folks are going to inverter machines) is a pretty viable way to get a decent commercial grade MIG welder and being able to run it on single phase home power.

I dont have any 3ph stick or tig machines, so I cannot give any data on what one of those would take to run.

YMMV of course.

Gunner, off to weld up a cart for that big bastard

It's better to be a red person in a blue state than a blue person in a red state. As a red person, if your blue neighbors turn into a mob at least you have a gun to protect yourself. As a blue person, your only hope is to appease the red mob with herbal tea and marinated tofu.

(Phil Garding)

Reply to
Gunner
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Hey Gunner - your old tofu eating buddy here.... We had a thread going on this before - can you give any specifics of how to wire the three phase to a 220 V single phase? Did you just hook the two lines in to two of the three phase ins? I've got an old beater 300amp continuous duty DC phase which I would really like to use. I don't have a DC stick welder other than this, and this has an auxiliary MIG wire feed unit, so it could be a great machine, if I can just feed it the right kind of juice. Thanks

John

Reply to
Doctor John

Reply to
Waynemak

Hey Gunner - your old tofu eating buddy here.... We had a thread going on this before - can you give any specifics of how to wire the three phase to a 220 V single phase? Did you just hook the two lines in to two of the three phase ins? I've got an old beater 300amp continuous duty DC phase which I would really like to use. I don't have a DC stick welder other than this, and this has an auxiliary MIG wire feed unit, so it could be a great machine, if I can just feed it the right kind of juice. Thanks

John

Reply to
Doctor John

John....I was running the welder on 3ph, generated by a Rotary phase converter, which is basicly just a 5 hp 3ph motor and some capaciters. You feed it single phase, and depending on how its built, it will either start itself, or you pull a rope wrapped around the motor shaft, to get it up to speed, at which point it generates the 3rd leg of power and gives you 3phase output. Mine happens to be an older..very old in fact commerical rotory phase converter, but there are any numbers of plans out there to build your own, using a surplus

3 phase motor, some relays and some capacitors.

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Ebay has some rotary phase converters also. You do NOT want a "static" converter or a VFD for welding use.

There is a gentleman who builds panels, and you simply add the proper sized surplus idler motor, that posts here on rec.crafts.metalworking occasionally and he used to sell them on Ebay reasonably, if you dont want to build your own from scratch.

As far as I know, only Inverter welders may be run from single phase, by simply dropping the third leg (L3) but it does downrate the output of the welder by about 1/3.

Gunner

It's better to be a red person in a blue state than a blue person in a red state. As a red person, if your blue neighbors turn into a mob at least you have a gun to protect yourself. As a blue person, your only hope is to appease the red mob with herbal tea and marinated tofu.

(Phil Garding)

Reply to
Gunner

Thanks, Gunner. I misunderstood the post. Not sure if I'm ready to dive into 3 phase converters - I may just sell the old beast and buy a 220 V DC stick welder.

John

Reply to
Doctor John

I have to testify - Gunner was in full smiling mode when I got there yesterday afternoon! - I was there to go through the treasure trove. Came back with treasure.

I think a motorcycle trailer would be a good start : Then a 10 HP tractor to haul it around the shop. :-)

Well the axle and frame might be a good start anyway.

Martin

Reply to
Martin H. Eastburn

Thanks for coming by Martin. You are a gentleman and a scholar. It was my deepest pleasure finally meeting you. Damned shame we didnt have more time to dig though the Stuff. I found other Stuff after you left I had thought you might like, and that vacuum pump is still sitting on the bench. I also have a nice takedown Rubbermaid workbench I thought you could use, it breaks down pretty well and doesnt weigh anything and we never did get a chance to get you some HSS tool steel, plastic and metal drops, etc out of the bins.

Respects and regards

Gunner

It's better to be a red person in a blue state than a blue person in a red state. As a red person, if your blue neighbors turn into a mob at least you have a gun to protect yourself. As a blue person, your only hope is to appease the red mob with herbal tea and marinated tofu.

(Phil Garding)

Reply to
Gunner

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