OK, I've never done it, but heard you can put 2 welders (in parallel or series?) to double the current. Also my question is...can you mix match types of welding power sources, as in a Miller Bobcat connected with a shop welder to accomplish this. Someone in their infinite expertise has provided us with low amperage machines and 1/4" carbons to gouge with.
"You go to war with the weapons we give you. Not the weapon you want"
Donald Rumsfeld
Now that is an interesting question...
I know you can wire 12 v batteries to get 24 v to start big engines (even little ones if you wanted to).
I know we did something like that in the late 70's to get more power for the plasma on the automatic cut off for the pipe forming rolls in a pipe manufacturing plant (18-144" pipe up to 3/4 wall).
But not sure how well that would work on small portables to air-arc. I would think it 'COULD' be done, the main question is rather it 'SHOULD' be done? Is it going to be a problem with the life expectancy of the machines and other factors.
I hope you get some really knowledgeable responses to this query. Would be one of those 'good to know for emergencies' bits of info.
Have a Great Day, Brent
Hello John, not meaning to be a smart azz, but if you do fry a couple of those machines will you be left high and dry or will this be an incentive for the powers that be to provide the proper equipment? I took a quick look at the schematics for one of our Mark VIII banks, they show connecting 1 to 8 of the positives to one carbon arc torch(parallel) and using a single common ground from the machine to increase the output of the machine(essentially parallelling the connections, 200 to 1600 amps output). I believe you could hook the 2 positives from two different machines to your carbon arc torch and the two grounds from these machines to the workpiece and go to work. So in other words, there shouldn't be an issue. If I get a chance I might try this theory out with a couple of our "older" machines and let you know the results. Good luck and best regards, Allan
Allan,
NO! The last thing I want to do is fry a machine. Lordy, with the military, it would take me 6 months for a replacement and then it's liable to be a Harbor freight POS. I am hoping to help the men in the shop for difficult removal projects. Some geometry does not allow for grinder and cut-off wheel access.
John, we do this on a daily basis. 90% of the time it is with electric machines like inverter banks or Mark VIII machines. However in the field I have on occasion found the need to parallel two small engine drives to carbon arc with. Set both machines at the same output current, if they have meters this is easy otherwise you have to just go by the dial or use an AMP Clamp. I have had two 305G's together, a Trailblazer and a 305G together and for a certain job we do on an annual basis we couple two Air Vantage 500's together. Most of the time we are able to use Magnesium Burning Bars for heavy material removal. I have never had the need to couple a shop machine to an engine drive but if both their output current is the same I don't see why it would not work.
So Wade,
I don't suppose you need to bank that 500D with anything else. Or are you even going beyond it's range?
Have a Great Day, Brent
Heck no! I don't do that kind of work at home. I was referring to work at the Mine. We have a huge leach pad and equipment ground pressure is a HUGE problem so we use the small air cooled machines out there. Did a bit of gouging with the 500D last weekend with 3/8 carbons and it was SWEET! Removed about 6' total of bird dropping weld on an end dump and fixed it up right. I am loving the machine especially with big wire now that I have the output to bun it
Good to hear. Glad it is working out for you.
I may be about to restart the job that I originally had bought that machine for. The place sold and so we have a new owner, contractor, bank, and slightly revised plans. Same engineer and Architect and maybe welder.
Anyway, with that job I may finally get to buy a smaller machine for replacing the 500D. Don't think I will need that much machine for how the job is coming together.
Have a Great Day, Brent
You will need to put the machines in Parallel, this adds the amperage of the two. Put both positives together for one lead and both negatives for the other. Asuming the shop welder is CC, set the Bobcat to CC too. I would not try to match the output of the 2 different machines, but set each to work within it's own duty cycle.
Do not try to coupple AC output machines, or an AC with a DC.
AC output TRANSFORMERS can be couppled ONLY if the phase is matched, that is a whole different subject.
Dave, when I was a younger man the seasoned vet who taught me told me to match the output of each machine. Usually we were dealing with 300 amp machines so I would always set them both at 250. To my limited understanding of DC current I do think it would be,,, possible to run one at a higher ampreage but in my experience 600+ amps is usually to much unless you are burning 1/2" carbons. Personally 1/2" is the largest carbon I have ever used or seen. I use magnesium burning bars for anything larger that needs to be removed. So my question would be why other than limiting combined amperage would it be fine to have one machine set at say 200amps and one set at 400amps? I don't see any reason that it would hurt the machine set at 200 but my understanding of DC current is basic.
My reasoning comes from not knowing if the machines have similar capacity. If the shop machine is a lighter duty machine, it may only have 30% duty cycle at rated output, and need to be set lower than the engine drive to keep from overloading it.
I think You were doing right by setting the machines the same, as they were similar machines.
CC welders are a bit different than hooking batteries together, as they have a high OCV that will drop when the arc is started. The amperage output of each will depend on the volt/ amper curve of each machine at the setting it is at, and the arc voltage.
I am no expert on air arc, been around it, but it was not under My job clasification at the plant, so I wasn't the one doing it. I have an Arcair setup, but have not needed to use it. From My understanding, He is going to need at least 250 amps for 1/4" carbons. The Bobcat mentioned might be a 225 or a 250, but probably shouldnt be run flat out for reasons of longevity, He didn't say what the other machine is. All the literature suggests that low OCV "farm welders" don't work well for air arc.
Thanks to all for the great responses and direction. We do have a Miller air pack sometimes at one shop. Other shops have only Bobcats or Trailblazers to support the hard wired shop machines, and the Big 40's not always available or even on location.
John.
this works best off of bank machines (rentals best option) with a common ground, then just tie two machines into one postive lead. It works great that way , but it can mess up engine driven machines I have done it they never was the same after that.
Do you have any plasma cutters? they work good for gouging also!
