Transformerless, non-isolated welder

[DerStrom8]

By the way, I included the definition list for my own understanding as well as others, who unlike you, may not be familiar with the many terms in the welding field.
What does AAC stand for. I have Googled it but no luck. If it is not for open publication can you PM me?

oops, have I already breached forum rules? What rule are we on the brink of? Sorry I haven't read them in a few years.

No worries strantor. You haven't broken any rules at this point. Generally posts regarding dangerous projects are left to the discretion of the moderators based on the experience level of the OP, and how the posts might be replicated by someone who does not have experience. For example, I have seen many Tesla coil posts here. Some were created by people who clearly did their research, who understand how they work, the dangers, and the safety precautions needed. The discussions are kept very open and clear to ensure that anyone else reading it also knows and understands the dangers associated with those sorts of projects. Other Tesla coil posts are clearly made by people who haven't done any research and have no electronics experience whatsoever. They don't know the dangers and just saw something that they thought looked cool and wanted to replicate. Threads like those, where even after several responses the OP still doesn't know what they're doing and shows no hope of learning, are closed because it endangers not only them, but anyone else following the thread.

If we see a post from someone that appears to not know what they're doing, we (the moderation staff) discuss it and determine whether or not to close the thread.

There are some topics that are absolutely not allowed:

Forbidden

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This exerpt comes from our Terms and Rules: https://www.electro-tech-online.com/threads/the-forum-rules-read-carefully.101939/

So far you're in the clear

Regards,
Matt

 

[dr pepper]

No I dont think you have, I would if I advised you to do something dangerous.

Edit: I hadnt seen the above post, double posted, but that clears it up.

 

[cowboybob]

Within the theme of this thread (transformer-less welders), but at the total opposite end of design:

I'm a "buzz" box welder (Lincoln, tapped transformer). Crude, but I can make a pretty bead between, for instance, a 1/4" thick pipe and a 1/32" tin flue pipe. Then cut the 1/4" pipe off with the same 1/8" stick (multiple sticks used, of course). I've also used TIG and MIG.

But the most basic welder I've ever seen (and NOT, in any way, a suggested design) was in a neighbor's basement (I think I was 9 or 10yo). Ran off of raw 240VAC (no ground). He had a wooden barrel filled with a brine of indeterminate concentration. One leg of the 240 ran to a metal rod immersed in the center brine. Another rod at the edge of the barrel ran to his stick holder. The other leg of the 240 ran to his "ground" (a "C" clamp). He wore a pair of 2 heavy rubber gloves. He would vary the current by adjusting the depth of the immersed rod. Actually achieved reasonably acceptable beads. Somehow managed to not kill himself.

Very, very SCaaary... .

 

[shortbus=]

I knew a guy that had one of those. My one grandpa had a stick welder he made from a couple of polepig cores, rewound with the original square copper wire, using oilcloth table cloths for insulation. The thing weighed a couple hundred pounds.

 

[tcmtech]

Well I was gone for the weekend helping a buddy with a home remodel job but now I am back.

Ohay. First of those 'Transformerless' welders are not transformerless any more than a common SMPS based power pack you plug into a wall is transformerless so given that NO YOU CAN NOT Just tweak the waveforms of the incoming power lines and run them through some big honkin' electronics N' stuff and use the common of the AC mains as the ground and make a safe reliable welding rig.

Yes it could be done but no it's not advisable and to be honest the amount of cost behind the higher powered electronics components you would need to make a live line powered welding rig would cost more than had you just went and bought a good used or even a broken welder and fixed it.

Believe me if you do even just a bit of asking around the odds are you can find someone with a used working or repairable welder for under $100. Even less if you are just wanting a basic CC stick unit.


Now as for AAC and the migration of members from there to here it's basically the 180 turn around of what happened here two or so years ago when a good deal of the upper level members here migrated over there due to moderator, site management and who's a sacred troll and who's not issues.

 

[strantor]

Yes it could be done but no it's not advisable and to be honest the amount of cost behind the higher powered electronics components you would need to make a live line powered welding rig would cost more than had you just went and bought a good used or even a broken welder and fixed it.

Believe me if you do even just a bit of asking around the odds are you can find someone with a used working or repairable welder for under $100. Even less if you are just wanting a basic CC stick unit.

Regarding asking around, I don't know anybody to ask. I've been checking Craigslist every day and haven't seen a single broken welder for sale. Seen a few Lincoln AC buzzboxes go for <$150 but that's the only thing I've seen come close to your $100 estimate.

Regarding the big expensive electronics needed to build one, i imagine most of that will be big capacitors. I have 2 dozen 4200uf 350v VFD DC bus caps the size of a can of spray paint but wider. I have a bunch of SCRs and diodes; the big beefy 5/8" stud kinds and the hockey puck sized kinds used in 100+hp DC drives. I also have MOSFET modules the size of cigar boxes. I think I got all the big expensive stuff covered.

What I don't have is a several KVA high freq inverter transformer. Hence why i dreamed this up.

But I'm letting the dream go, so no worries. If I pursue a welder build, I'll be using some big iron 60hz transformer cores I have and go with conventional methods.

 

[tcmtech]

Well then you're good to go no the high power components end.

Sounds like you scrap out similar high powered things as I do.

 

[strantor]

Well then you're good to go no the high power components end.

Sounds like you scrap out similar high powered things as I do.

The place I used to work was an industrial automation shop. I was a field service tech; i troubleshot AC & DC drives, PLCs, and misc controls in the field. Rarely did open heart surgery in the field though, if something was hurt that bad it came back to the shop and the Board Repair dept. would perform the transistorectomy or whatever it needed. Usually they replaced a bunch of stuff since there was a warranty on their work. If a DC bus cap blew, they would replace all of them. If and SCR pack failed, all 3 got replaced. So, while I didn't have the privilege of scrapping out the stuff myself, I did have access (and admin blessing) to raid the Scrap Bin of Untold Bounty, AKA E-Waste Nirvana.

Sadly, that resource has been extinguished.