Batteries and a PWM for Stick Welding?

Oops. Misread the chart, sorry.

A better resistor might be 1/8" stainless rod. I measured a length of

1/16" stainless TIG rod, calulated resistivity to be 7.1 E -07 ohm-meter. I figure that about 43 inches of 1/8" dia stainless rod would be about 0.1 ohm.

Another possibility might be the heavy iron (steel?) wire used to bind rebar with. Don't know the resistivity of that offhand.

24 volts is plenty to get an arc started. Wirefeed welders do it routinely.

If you could make (or scrounge) a wirefeed mechanism, your batteries and PWM could make a dandy wire welder, either for MIG (with gas) or fluxcore wire (no gas). That is a constant-voltage process.

I have to corect this value a bit. It is the minimum value (depends). The value is from 0,2..0.4V/A (not wax oof to what I saied

Yes, maybe not a good, but a working one. The reason why the voltage has to drop on increasing load is to ´keep the arc stable. Is is especials important with stick welding, because it is _you_ who controls the arc length. If the arc length increases, resitance increases and to keep the current (at about) steady voltage has to increase. But a resistor is not the best solution. It doesn't matter, you want to use your golf cart controller.

You do the math, I had some beer. :-)

You do the math ... If #10 (I'm metric!) withstands the curren? I donnot know where I have read this, but somehow I think that somewone has bulit a watercooled resistor for arc welding. You can also use the resistor for the necessary coil. But I really don't know how mand Henry it has to have. Not the slightest clue. I only know that if it is too low, your PWM will go up in smoke. I also know that high end buzz boxes do switch inductance, depending on the current.

Why? Whatfor?

Because they (others) saied, that 40 Volts aren't enough to start the arc? Be assured, that 40 V are reasonable. There is a norm in Germany that limits most buzz boxes to 42 volts, and they do start an arc without any electronic gimmics.

And please don't forget to read the concerns about hydrogen gas, as others saied. This _is_ an issue!

HTH, Nick

I think you can start an arc at 40V in Germany because of Spaten and Paulaner beer steadying your hands.

Can't do it on Bud over here. (:

In the labs, we used a carbon stack - that is a 8x8" end profile - about 2 feet long. Connection plates are at the ends. To change the resistance, one simply cranks down or up on the screw. One time, mind you only one time - we got the stack smoking. When we saw the smoke - we figured we toasted the stack. Not exactly.

Martin

Was the carbon used to control battery stick welding?

BoyntonStu

Augustiner does the job! (also from Munic)

Maybe you should try a _beer_, not a Bud :-)

Nick

DC also has two rails. A golfcart PWM controller is indeed a DC controller that does not produce AC PWM.

???

I get a lot of those.

Check your notes, Nick. Have another brew.

I'm smelling troll here. Out.

Here ......

Thanks Karl

What kind of tactics are you using? First say that I'm wrong and later say exactly what I did? Just to make you look clever?

Oh? You don't understand that? OK, read your own postings and see that it needs modifications in the PWM controller to make it a current source. Then rethink your "???". Tactics?

Well, quite funny. So what did I say wrong? You just made the explanation more complicated (to confuse the OP?), to get a chance to contradict me and then in the end say (indirectly) that we both said the same? Tactics?

Troll? I pointed out that in the end we came to the same result. If you didn't get that, I'm sorry. I'm an EASL.

No need to answer, EOT (read EndOfTactics + EndOfThread. I'm not gonna play your game any further)

Nick

No - more current that that. We were testing a 1000 amp power supply that was IEEE controlled and was to be driven to power up devices. Yea, IC's - the company (customer) never got that high, but almost - they got to 600 amps.

Wild times and high tech low tech methods. The power supply lead had to have the sense line not run along the line of the + and - for the two senses - but corkscrewed down the single lead - two corkscrewed and that added just enough impedance (reactance) to limit the almost instant response for the servo system that would drive more or less current. We also had to put both electrolytic and poly caps on the supply posts.

The long line bringing high current has high electric fields but the distance is almost zero electrical time.

Martin

the current - likely to a safe level and still allowed a weld.

I think a jumper cable set would have been an improvement and then limit the current at the stick side or better the 'gnd' side away from the moving stick.

Martin