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Transformerless, non-isolated welder

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As an aside, this is the sort of rig I have an eye on for when I get a workshop up and running: **broken link removed**

Unfortunately it does not have AC TIG

It is a badge engineered product under the auspices of Victor Industries, formerly Thermalark
 
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I had a thought this morning that might explain why all the welders use transformers (whether 60hz "welding" transformers, or high freq inverter transformers): as spec has pointed out, in my design the neutral is exposed, and actually clamped to the workpiece. I don't think that this poses a safety hazard, but it does give current an alternate path back to the source if the workpiece is earthed (typical, sitting on an earthed metal table / bench). This welder could almost certainly not be used if a GFCI were installed.
 
spec said:
As an aside, this is the sort of rig I have an eye on for when I get a workshop up and running: **broken link removed**

Unfortunately it does not have AC TIG

It is a badge engineered product under the auspices of Victor Industries, formerly Thermalark
Click to expand...

Here's the one I was saving up for before I got the crazy notion to build one. It can TIG weld aluminum.
**broken link removed**
 
strantor,

About making your own welder- like you I have considered this, especially in the days when cash was tight. But the position is that you would have one hell of a job developing building and testing a rig with the facilities and performance of the sort of machine that we would both like to own. Yes it would be possible, but, I hate to say this, impracticable.

What might be worth considering is adding an AC inverter, to allow aluminum welding, to a basic high current MMA or TIG rig. The best source of components would be faulty rigs which you can get quite cheaply.

Even so, I think we would be better off just biting the bullet and buying new or second hand. You could soon recoup the cash if necessary by doing a few welding jobs here and there. When I had access to a MIG welder it was surprising how many people wanted the odd bit of welding done here and there- often repairs to garden gates.

spec
 
ClydeCrashKop said:
In plasma cutting the work piece & table are positive. Can you use just the negative side of the 230 volts so the table is neutral / grounded?

There are a few AC tig welders on ebay now in the $500 to $600 range.


https://www.ebay.com/itm/IGBT-INVERTER-AC-DC-TIG-MMA-Aluminum-Welder-TSE200G-new-generation-of-WSME-200/231603703152?_trksid=p2047675.c100010.m2109&_trkparms=aid=222007&algo=SIC.MBE&ao=1&asc=34492&meid=0d8a3ef3b43448438f6fac2d54c0ace4&pid=100010&rk=1&rkt=18&mehot=pp&sd=262197238831
Click to expand...
Yeah that was the plan. By rectifying the top half and bottom half separately, that would allow me to make the clamp positive or negative with respect to the electrode, without actually changing the clamps potential with respect to earth.
 
spec said:
strantor,

About making your own welder- like you I have considered this, especially in the days when cash was tight. But the position is that you would have one hell of a job developing building and testing a rig with the facilities and performance of the sort of machine that we would both like to own. Yes it would be possible, but, I hate to say this, impracticable.

What might be worth considering is adding an AC inverter, to allow aluminum welding, to a basic high current MMA or TIG rig. The best source of components would be faulty rigs which you can get quite cheaply.

Even so, I think we would be better off just biting the bullet and buying new or second hand. You could soon recoup the cash if necessary by doing a few welding jobs here and there. When I had access to a MIG welder it was surprising how many people wanted the odd bit of welding done here and there- often repairs to garden gates.

spec
Click to expand...

Yeah I know you're right. But I kinda want to build a welder anyway. I think it would be an awesome project. Problem is I actually need the welder for welding, soon. I'll probabky end up buying one as you suggest. Then later i can build its replacement and sell it. This would give me something to reverse engineer, too.
 
strantor said:
Yeah I know you're right. But I kinda want to build a welder anyway. I think it would be an awesome project. Problem is I actually need the welder for welding, soon. I'll probabky end up buying one as you suggest. Then later i can build its replacement and sell it. This would give me something to reverse engineer, too.
Click to expand...
Man after my own heart. An older engineer from the labs at work put things in perspective. He said sit down and do a schedule of all the DIY tasks you have in the pipeline and see how practical your dreams are. He said he did it one day and discovered that he would need to live to around 90 to complete even his current projects. I did the same exorcise and saw the light.

If you had that welder that you linked to, I'm sure you would not be interested in building your own welder for long. No, if I read you right, you will be moving on to your next advanced venture. I did exactly the same thing with multimeters, scopes and PSUs. But I did learn an awful lot designing and building those items. Take scopes for example, I designed and built three, after a fashion. Then one day, a colleague offered me a faulty Gould OSX1000 for £5. I fixed the Gould in a couple of days and it was far better than anything I could have built in a lifetime. It was such a godsend just to turn the scope on and use it... like a tool.
 
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strantor said:
Here's the one I was saving up for before I got the crazy notion to build one. It can TIG weld aluminum.
**broken link removed**
Click to expand...

Don't know about that specific machine, but, those type of "do everything" machines don't usually do anything well. Mig and stick use the same basic type supply, meaning many big industrial machines use a wire feeder on a stick machine, for the Mig. But Tig is different and to be most effective needs HF for start of weld. Know I'll probably get some kickback for saying this, but this has been my experience in my 55 years of doing welding/fabricating.

Strantor, do you check Craigslist? With the economy the way it is, I see stuff like this for sale all the time.
 
shortbus= said:
Don't know about that specific machine, but, those type of "do everything" machines don't usually do anything well. Mig and stick use the same basic type supply, meaning many big industrial machines use a wire feeder on a stick machine, for the Mig. But Tig is different and to be most effective needs HF for start of weld. Know I'll probably get some kickback for saying this, but this has been my experience in my 55 years of doing welding/fabricating.

Strantor, do you check Craigslist? With the economy the way it is, I see stuff like this for sale all the time.
Click to expand...

I generally agree with your "jack of all trades, master of none" assessment, but i settled on that welder as my "must have" after years of here-&-there occasional consumer research. I don't even think Everlast welders existed when I started looking; they're relatively new. But the reviews Ive read about them are excellent. What ive boiled out of many many reviews by professionals is that the only reason not to buy one of these everlast multiprocess outfits is speed/convenience. If you have a separate tig and plasma machine, you just set the tig torch down, grab the plasma, cut, set the cutting torch down, grab the tig torch, weld. With the everlast unit, you have to swap torch leads, gas bottles, etc. every time you swap processes. It seems to be perfectly suited to my needs, which don't include assembly line efficiency.
 
spec said:
Man after my own heart. An older engineer from the labs at work put things in perspective. He said sit down and do a schedule of all the DIY tasks you have in the pipeline and see how practical your dreams are. He said he did it one day and discovered that he would need to live to around 90 to complete even his current projects. I did the same exorcise and saw the light.

If you had that welder that you linked too, I'm sure you would not be interested in building your own welder for long. No, if I read you right, you will be moving on to your next advanced venture. I did exactly the same thing with multimeters, scopes and PSUs. But I did learn an awful lot designing and building those items. Take scopes for example, I designed and built three, after a fashion. Then one day, a colleague offered me a faulty Gould OSX1000 for £5. I fixed the Gould in a couple of days and it was far better than anything I could have built in a lifetime. It was such a godsend just to turn the scope on and use it... like a tool.
Click to expand...
Again, you're probably exactly right.
 
I'm intrigued- in summary, what is going on at AAC for so many people to be so cheesed?
 
strantor said:
design the neutral is exposed, and actually clamped to the workpiece. I don't think that this poses a safety hazard, but it does give current an alternate path back to the source if the workpiece is .
Click to expand...
In the areas and jurisdictions I have worked in it is against the code to re-reference a neutral to ground, Unless Galvanic isolation of the supply exists or in place.
Max.
 
MaxHeadRoom78 said:
In the areas and jurisdictions I have worked in it is against the code to re-reference a neutral to ground, Unless Galvanic isolation of the supply exists or in place.
Max.
Click to expand...
Now you're way outside my wheelhouse. I'm not a master of American electrical code, much less Canadian.

Just the idea of this thing needing to meet code is a question in my book. It's not a physical installation, it's a device that plugs into the wall. So to me that smells more like UL than NEC. Not sure what UL says about it, but I think it's a safe assumption my device would fail their scrutiny. That fact (fact? I think?) That it would trip a GFCI should confirm the notion.
 
A vfd drive works into a inductive/resistive load, weld sets basically drive a short circuit load.
Its possible to control current with a switched choke, however for tig and mma welding you need to have around 60v to get a good strike, rectified mains would be around 320v, ok for plasma cutting but not a lot else.
I dont really wantto advise any more as such a machine would be dangerous and I'd be in breach of forum rules.
 
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