Arc Force Question

[Rambozo]

People have also be telling me that this unit may not be made to run for 5 hours (or more) of straight welding. Any truth to that?

You do need to stay within the duty cycle. So do not exceed 6 minutes out of every 10. Usually that isn't a problem when constructing something, but with just practice, running bead after bead, you might reach that and need to let it cool off some.

[performance]

Alright, I'll have another go at it. Today maybe. The 85 amps was what got me the best results so far. I started at 50 and worked my way up. The hobart 6011s 3/32" ran well hotter, at around 95amps. I'll dial it down some more and see. People have also be telling me that this unit may not be made to run for 5 hours (or more) of straight welding. Any truth to that?

At 85 amps for 6011 3/32s to 95 amps? No wonder you are smoking the rod. Turn it down to about 65-80. That's all you'll need to run a 3/32 cellulose rod with a welder with arc force control. You can watch this video here about how I used it. This was on 120V too at 80 amps. http://www.youtube.com/watch?v=mCFXzL4BvJY

As far as being able to weld 5 hours in a day, that depends on the amperage and duty cycle. Shouldn't be any limitations if you are welding within the duty cycle limits of the welder. Can you cite exactly what was said about it not being able to weld 5 hours straight?

[Tanh]

Hey Mark,

Thanks for the tip. I was just going by what was on the packaging. It did seem to stick less at those amps but I'll definitely give lower amps ago. Sharpen up that technique.

As for citing the 5 hour rule, it's was put to me another way. In a pm with Duncan, he says that if you're pushing the machine to the limit of the duty cycle but not hitting it yet, the electronics can still act up. This is paraphrasing from my understanding. And I think that's a reasonable explanation, although a little less tangible than I'd like.

[performance]

There's no 5 hour rule that I am aware of. Never heard of it. If the units are used within the capacity of the machine the welders are fine. We don't have a high rate of repair with these units...However, if you need to use it 5 hours a day everyday, you've got the wrong welder. Something like the PowerArc 200 is better. NO welder works well for long if you push the duty cycle day in and day out. Old transformers with 100% duty cycle way back in the day would not mind it, but small inexpensive (relatively so) tranformer buzzboxes do not like the duty cycle being pushed for long and they won't hold up. But if you were to buy something like the ideal arc, then you'd never see an issue. The unit is plenty capable, but it isn't a commercial class unit, if that is what the context was. It doesn't mean it can' t be used to weld commercially, but it does mean it should not be expected to handle rough welding jobs day in and day out. It doesn't have enough amperage, for one, and for two, it doesn't have enough duty cycle to make it into the commercial class, though you find other companies that will try to lump 35% duty cycle stick/tig units into a commercial/industrial class. Years ago, the standard was 60% and still should be, but you have marketing wienie brains that want to stretch the "meaning" of words to sell more low end product, because of higher proft margins, and higher sales volume capabilities.

[Rambozo]

Heat is the enemy of electronics. If you are constantly running near the limit, it is bound to shorten the lifespan. On the other hand if you are running it under light load and keeping it cool, it will last much longer. Duty cycle is also influenced by input voltage, ambient temperature, even arc length will have an effect. I would always buy a machine with some headroom for the typical workload. They always do much better that way, no matter the brand. If you need 140 amps all the time, day in day out, this is probably not the right machine for that. I expected to do 90% of welding between 50 and 100 amps, so this machine fits the bill very nicely. The portability is the big thing for me. This machine can go places my others can't.

EDIT: I guess I type too slow.

[agent4573]

I always thought you were supposed to go ~40-50% over on the amps too when sizing a welder. So if you were going to weld in the 150 amps range every day, then a 225 amp welder would do it without thinking twice. If you were going to be welding 1/4 inch plate 8 hours a day then a 300 amp welder would keep you in the sweet spot of duty cycle without having to worry about frying electronics. Thats how I always viewed it anyway. But then again, I never bought a machine I was planning on using for more than a hobby box, so a commercial box for heavy use isn't my real cup of tea.

[Tanh]

The shop I was in a few years ago reconditioned heavy machinery. There was a repair welder there that jumped around to different stations. A miller Idealarc or something similar, not too sure. The thing ran hot but only had 10% duty cycle. They always said it was enough and I gathered it would be, not considering the toll time takes on electronic components. Setup takes a few minutes and welding would be a few seconds. Then disconnecting the rig and moving it before setting it up for another job. It never hit 10% or even 5%, I'm sure.

The workload was mismatched to this welder and I see now that I need something substancially bigger to keep up. I originally bought the 140st for odd jobs / repair around the house. When I got it though, all of a sudden bigger projects keep popping up. In the spring I have a trailer that needs to be reconditioned and wondering if this little guy can handle it now. Maybe with a lot of coffee breaks. Kinda like working for the town!

There is no 5 hour rule. That was a tongue in cheek comment. This unit will probably work best for me as a low amp tig unit, while I get something more beefy for projects. Many people on the forum have more than 1 welder and I now know why.

[Rambozo]

A lot of times you can adjust the job to better suit the welder, too. For example when building some things, I have made exact drawings and pre-cut all the material. Then it will be all tacked up and welded out pretty much non-stop. For that I want a machine with plenty of reserve capacity. On the other hand for some things, especially repairs, I will cut a piece, fit it, tack it, then weld it in, before measuring out the next piece, cutting, fitting, etc... So for that kind of work even a small machine is fine. The machine is always waiting on me, not the other way around. If you work in that fashion you will not hit the duty cycle limits. Just break the job down into parts and adjust the parts so that all the welding isn't bunched together.

I have to deal with the same thing when some people ask for fast computers, when the speed of the computer isn't the productivity problem. PEBKAC!

[Tanh]

When I was building the table, I had all the lengths precut and ready for assembly. I guess this lumped all the welding within such close time frames that the welder did not have enough time to cool properly. Maybe next time I'll cut to order so to speak and space welding entervals between cutting, fitup and assembly. That should work better for the welder but seems too slow a pace for me.

The table is as done as it's gona get but I haven't updated the thread yet. Hopefully soon and I can show some of the nasty beads I ran.

[MuttonHawg]

I have a question about Everlast's implementation of arc force. Does the control adjust the amount of voltage drop before the current increases, the amount of current increase or both? Are there any published curves or graphs of the function? And how about the adaptive arc force used on some models? Just curious.

I too would love to see some graphs, because it would help me visualize what's going on. I've read a few explanations about what's going on electrically when welding (particularly constant-current welding) that were confusing because concepts and units were all scrambled up (for instance, watts being used as a measure of electrical current). I did find one generalized voltage-vs-current graph online (on Miller's website, I think), and that basically allowed me to wrap my head around the fundamentals of what's going on electrically. But having a graph of how the PowerArc 140ST manages volts and amps, versus how the PowerArc 300 manages them with different arc force settings, would be extremely interesting (to me, anyway).

[MuttonHawg]

Does the PowerArc 140ST have an arc force function to ramp up current if the voltage drops, even if it's not adjustable with a knob?

Nevermind - just read through the features grid and found my answer - yes it does (auto-regulated).