sounds like you could basicly take 2 motors, one the drive off a/c current - one would be rewired to be used to switch polarity being fed by the stick welder.

in an M-G set, yes. you can use whatever you want for the motor, whether it's DC, AC or whatever, and MAKE whatever current type you desire. you can technically make 12VDC into 480VAC 3 phase power.
thats how rotary phase converters work.. theres two types on that, static (using capacitors) and dynamic (using an actual 3ph. generator)

but as far as what i want to do, i'm looking to build a compact "power supply" of sorts that will convet my stick welder into having high-freq TIG capabilities.. since transformers transmit their input noise and transients to the output, that shows that ifyou'd power a transformer with oh, lets say a sawtooth wave, then you'll have a sawtooth wave on the output. if you ran a squarewave into the primary, you'll get a squarewave out of the secondary.

therefore, if i use a variable freq industrial motor drive, (which pretty much generate squre waves) i can modulate the output from the welder depending on the drive settings. if i wanted to run the welder at 120Hz, just go into the parameter and punch in 120. if i wanted 225Hz, same deal. they're good for about 400Hz, depending on the model.

the square wave is really important in TIG welding evidently, so i'm gonna try to maintain that waveform as an input to my welder.

For a moment I thought I was reading a Worlok post... :)

Hendrix,
You may want to use a shielded transformer, so the natural eddy currents in the transformer will be at a minimal level,and will keep your sign wave cleaner and more true to form with the square wave output of the VFD.
And we are the most supreme wiring, designing and fabricatin MO-FO's of the universe, "the Man" x 2! ( just for the Srob..........LOL)

"You see Vern the problem is your catastrophic converter" Know what I mean Vern?

http://jimvarney.org/ernest.jpg

Ha Ha, old Ernest T, havent seen him in a while!

lmao, sro and deej!

ya sro.. i'm the man. i can't help it.. some ppl are just born that way!:D

i've been hacking things apart since i was 4.. surprisingly, i've been putting them backtogether in various conditions since about 5 or 6..;)



worlok!!! .. c'mon man!! the only sine wave there will be will be going into the VFD from the wall outlet! lol

its all modulated waves from there on out bro...

i do believe the welder is pretty shielded.. its got a copper wrap around the windings and its enclosed in a metal box thats grounded.. RF alone will not transmit.. not sure if you've ever studied the effects of EMP and RF transmission, but they don't like metal. i almost went to get an electronics engineering degree on top of the electrical, but i just don't have the money!!

but ya.. the vfd itself will be uber "clean" since they're designed to be installed in sealed cabinets with other electronic things.. you ever see inside a big vector drive? EVERYTHINGS wrapped in copper and grounded out..

Not be a buzz kill or anything, but I dare say that you will be better off to just go out and buy a purpose built TIG welder. You'll most likely spend less money than what you will on this contraption especially when you factor in all your time, burned up parts, and trial and error. And it will actually work. :) Not to mention, you will have it immediately and can move on to your actual project, instead of gearing up for your project and I suspect building a working welder may be a never ending project, you will always be tweaking, fine tuning, trying to get it right, just one more adjustment, etc, etc.

Don't get me wrong, I build a lot of custom things. But I save my valuable time and effort for those things that only I can do. If I can buy a machine/service/information that already exists and does what I want for a fair price, then I'll choose that option every time, unless I just want the learning experience of doing that particular thing, but then that's a whole other thing though with a different cost/benefit system.

But my advice is that if you need a TIG welder to use as a launching platform for your other ideas, then don't waste your valuable talent building the welder. Get a loan if you have to and buy the best one you can afford that does what you need. Then USE it to launch your ideas. And then sell those ideas, inventions, services, etc for a profit and pay for the welder 100 times over.

On the other hand, you could easily spend as much on a home made welder, work on it for months, and it may never work adequately. At the very least, you have lost valuable time where you could have been turning a profit using your machine than if you had just bought a decent Miller or something.

THINK! Where is your unique talent that no one else but you can do? Is is building the welder? Or is it with what you can do with the welder?

well, you definitely have a point..

oh i'd 100% most certainly by a TIG and a plasma cutter and all those goodies, if i could get a loan, had credit, or money!! man, i'd LOVE to have a brand new 350 synchrowave in my shop with a water cooled torch and a thermal dynamics uber plasma cutter sitting beside it, but, i'm poor..lol

i'll have it eventually.. i'm just always curious as to if i have the capability to do something outlandish as this. if i had to go buy a welder, and buy this and that, absolutely the cost would offset quickly and i'd be paying more to build a questionable rig than to purchase proven technology, but in my theory, i do believe it'll work.. this is basically just to get me by, and i won't be welding a customers machine with this.. if it works, great!! if not, then i've experimented and learned something, which, to me, in itself is far more valuable than purchasing someone elses brilliance.. as you've already noted.. lol

you are certainly right tho.. but like i said.. if i had the money, i'd have everything i need. i appreciate your input tho!