AC Welder to DC conversion.

Soundguy · Apr 8, 2006

For those interested.. the D1-D4 outgoing wire to the load will be the positive terminal. The D2-D3 outgoing wire will be the negative terminal. You can get creative with high current nife and slider switches to make dcen/ep easier to change.. or even use probe sockets to swap leads.. though swapping the electrode holder and ground clamp works too.

Soundguy

Highbeam · Apr 10, 2006

I was always told, and believed, that the welding output is 25 volts while welding. 200 amps for 5000 watts. That is why I can use the 225 setting with my 5500/6850 watt generator. At 80 volts, the AC225 would need more than 16000 watts. I don't believe that that is correct. Perhaps you were thinking 80 volts before the current flows.

Maybe we can just buy the part from Lincoln. It seems easy to you folks but I even took the electricity and magnetism physics class and can't apply the cartoon to real life.

DC also greatly improves out of position welding.

Soundguy · Apr 11, 2006

My buzzbox lists it's output between 26 and 32 volts. I'll assume RMS. Perhaps the 80v number is a peak to peak rating?

Soundguy

TruChaos · Apr 11, 2006

I agree, the 80 volts sounds way too high. It would be unsafe to weld with high voltage as most people are accustomed to.

If you're actually seeing 80 volts perhaps its a no load voltage which drops considerably when heavily loaded. Remember, that big tranformer is unregulated and the voltage will fluctuate quite a bit. Having said that, touching an 80 volt electode could be lethal under the right conditions. Your body wouldn't load the output enough to bring the voltage down to a low range.

I'm going to quess the 80 volt's figure is an error. What size circuit breaker is it connected to? If it's not in the 80 to 100 amp range, at 220volts, the 80 volts is incorrect.

Jerry

GaryE · Apr 11, 2006

DC also greatly improves out of position welding.


I do agree, but there is a new 7018 AC rod that works real well for vertical and overhead welding. For those with AC only it is worth looking into.

Gary

PILOON · Apr 11, 2006

I have welded using a Hammond transformer that had a 24volt 25 amp output using 1/16" 6013 rod.
Fixed lots of the kids bikes and snowblowers with this rig.

Lots of farmers used to use WW2 aircraft generators (28voltsDC) to weld.

With the hammond rig striking the arc was not easy, but welds held good once going with OK penetration
On the primary is protected with a 20 amp CB that popped occasionaly if i stuck a rod.
Using 20 amps x 110v=2200/25=88 amps to weld with on the rod.
I remember using charts to select a rod range that should work, tried it, and it did.
I still have that little rig, but it has been years since I used it.

I bet if I added a few more turns on the 24v side I'd have a super little rig.

You can also weld with 2 car batteries (24VDC) in series for excellent welds. 3 is even better.

As sound guy says, the 'open circuit' is higher (I understood it to be in the 70vdc range) but the actual welding takes place down around the 25-35 range.
Higher opencircuit voltage is what enables striking the ark but when welding you are loading, practically shorting, the output.

slowzuki · Apr 12, 2006

piloon is spot on for arc welders. MIG's are different being a constant voltage process.

Plasma cutter have high like 100V voltages and there is a much higher electrocution risk with them. The manual warns about not becoming part of the ground circuit.

Soundguy · Apr 12, 2006

( agree, the 80 volts sounds way too high. It would be unsafe to weld with high voltage as most people are acc )

Applying a little math.. and a little less guess.. I really think the 80v number is a 'peak to peak' number... IE.. for instance... when we talk about electric outlet voltages.. eg.. 120v.. that is an RMS number.. ( root mean square ).. the rms number is .707(peak) that is about 70% of the peak voltage reading. Peak votlage reading is just one side of the sine wave.. that is from 0 to zenith of wave form. Peak to peak are both the wave forms. that is.. zenith to zenith. So.. take peak to peak voltage, halve it to get peak.. then muliply by .707 and you get the rms number.. for instance.. 80v pk/pk = 40vpk = 28.28v.. or more what we see when welding. ( why all the different voltages.. well.. to make it simple.. rms lets you compair 'work' done by an ac current vs dc current.. )

Soundguy

TruChaos · Apr 14, 2006

Sure, I understand RMS voltages but 80 volts still doesn't sound right. I'm by no means a welding expert so I'll have to fire up my Hobart tonight and measure the electrode voltages at the high and low ends of the current range.

Welding at 80 volts is not the problem. What raises my concern is the hazard of having a 80v electrode voltage, circuit breakered at a very high current with no GFI protection. It just doesn't sound like something that would survive long in our litigious society. I've certainly seen people welding in wet conditions or light rain, so it would be dangerous.

Soundguy, I'll take those AC measurements in both peak and RMS just for you. : )

Jerry

BloomingtonMike · Apr 14, 2006

So I used the Lincoln IdeaArc Welder today and converted my King Kutter Carry All to work with John Deere's Imatch. I of course was using it AC and I was using 6011 electrodes. I am definately not good enough that it makes difference using AC or DC. 6011, 6013, and 7018 electrodes all work just fine with AC as well. I may not have the need to convert unless I just want to do it as a project - that list is very long as well.