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05-19-2013, 03:41 PM #1
Question about transformers and Miller Syncrowave 500 square wave TIG welder
I am attempting to install a big industrial welder into our modest little machine shop. I've had the welder for some 12 years but only now do I have the place and the power to get it going.
It is a single phase welder. It is currently set for 460V but can easily be reconfigured to 230V by simply rearranging some jumpers.
In "balanced" condition the welder requires 200 amps in at 230V and full power. In "unbalanced" condition the required input is 300 amps at 230V.
I have only a 200 amp, 230V, single phase service. I have installed the electric distribution in a manner such that I can shut down all the power to the rest of the shop and deliver the full 200 amps to the welder.
As a practical matter, I cannot imagine this ever being necessary unless we undertake to weld up a cracked aluminum cylinder head or something similar.
What I'd like to know is this: IS THERE ANY COMPELLING ADVANTAGE TO BUYING A SINGLE PHASE 230V --> 460V TRANSFORMER AND PUTTING IT BETWEEN THE BREAKER PANEL AND THE WELDER?
The only advantage I can think of is that it would enable me to run smaller gauge wire. However, the run is so short that this is of scant concern.
The part I'm not clear on is: Although the welder would be pulling only 100 amps at full power does this mean that only 100 amps of 230V are required to feed the transformer?
Stated another way, would a transformer reduce the load on the feed side? Increase the load? Or make no difference?
Thanks for helping me understand.
05-19-2013, 04:38 PM #2
It will make no difference at the breaker but I am puzzled by the ''balanced- unbalanced'' condition?
05-19-2013, 04:53 PM #3
No, unless youre incapable of setting jumpers.
In fact, I think there are compelling reasons NOT to put a step-up transformer in between your incoming power and the welder.
Consider that the transformer loses some % of input power that is wasted as heat and to hysteresis. You can use the transformers rated power factor as an approximation of the % that makes it from the input side to the output side.
Consider also that when you shut power to the welder off, its (probably) completely off and drawing no more power (control electrics on some fancy machines excepted). The transformer is still drawing some power which may not be considerable, but you probably don't want to unplug it every time either.
I ran a Linde UCC-305 welder in my parents garage before I moved out, the manual said it could draw 94 amps @ 230 Vac at full tilt, my parents house only has 100A service and depending on what was running in the rest of the house it wouldn't be hard to push over that 100A limit. I wasn't running full tilt often (hardly ever in fact) and it didn't cause problems, didn't even trip the 60A breaker when I did. The key is to size your breaker correctly and know the limits of your machine and power distribution system. Worse comes to worse you just have to walk across the shop and reset a tripped breaker.
05-19-2013, 04:54 PM #4
05-19-2013, 05:19 PM #5
I dont fully understand it either. But the syncrowave welders were "square wave" machines
Essentially this means the welding arc could be programmed or "shaped" which is to say "tailored" to overcome various welding difficulties -- especially aluminum.
One of thes adjustable parameters was the ability to program the percentage of the time the wave spends or dwells on either the positive or negative side of ground when welding on ac which is all but mandatory when welding aluminum.
I may get this backwards but when the wave is on the negative half cycle it jumps from the work into the electrode thus "parting the waters" of the oxide on the surface -- thus "cleaning" the weld puddle. Conversely on the positive half cycle you get "penetration" or "dig".
"Balanced" means the natural 50 - 50 cycle inherent to AC. Conversely "imbalanced" means the operator has overridden this.
All of the above is based on my reading and not on experience.
Regards to all.
Sent from my LG phone
05-19-2013, 06:22 PM #6
The "balance" is probably referring to power factor correction.
Welders pull less amps if they have a built in power factor correction unit. Usually the models with have a PF after it. Like Synchrowace 500PF. I don't think a lot of welders have these units.
The problem you will have is with nuisance trips on the breaker when striking an arc. The electric code allows you to use a breaker up to twice the size of the "standard" branch circuit size.
For example, my DialArc requires wires sized for 90 amps when calculated with the duty cycle and no power factor correction. So I need #4 wire. However, I can use up at a 180A breaker. I use a 100A and It works fine.
Your welder needs some freaking huge wire. The manual says 1/0 conductors, #4 ground and a 250A breaker. You can run that size wire and hook it up to your 200A breaker and it should be fine.
Personally, I would sell it or scrap it. That is the biggest welder I've ever even heard of. Even if you never come close to the rated output, it will consume a lot of power just sitting there with the huge transformer humming. It's also going to cost a fortune to wire it.
05-19-2013, 07:04 PM #7
I am aware that it will use some serious power. ut on the other hand it offers some astounding capability. For example it will deliver 400 amps at 100% duty xcycle. It delivers 500 amps at 60% duty cycle and 625 amps at 40%.
Whether we will ever need that kind of oomph is an entirely different matter. But buddy if there ever was a welder you wont outgrow this is it.
And it is unlikely to be stolen although the transformer alone would scrap for a pretty penny.
ut your points are true and well taken. e hope to find an inverter machine for regular work and find work for this machine that nobody else can do. If that doesnt transpire we will indeed sell or scrap it.
As to wiring it I plan to use 3/0 flexible 4 conductor tray cable. It costs about $8.50 a foot and will deliver 175 amps.
05-19-2013, 07:16 PM #8
So you need a 1/4" tungsten and some 3/16" filler rod? I bet it takes some work to unwind the leads.
My welder will do 310 amps AC at some low duty cycle. 200 amps is enough to get my gloves smoking in just a few seconds. I can't imagine more. That thing must be a beast.
05-19-2013, 07:23 PM #9
Balanced refers to the adjustment of clean/dig while welding with the ac necessary to weld ali.
Either more positive electrode or negative.
Takes a lot more juice to weld with an unbalanced arc.
05-20-2013, 07:33 AM #10
05-20-2013, 07:45 AM #11
200 amp circuit for a welder. Wow! That's a lot of juice! My house only has 200 amps. I'd be more inclined to get a smaller welder and do some passes. LOL.
05-20-2013, 09:00 AM #12
The machine does have water cooling. However, according to what I've read the difference between the 200 amps it requires in "balanced" condition and the 300 amps needed in "fully unbalanced" condition does indeed relate to the overriding of the 50/50 half cycle to one side or the other (+ or -) of ground. As Heavy Metal said, it relates to cleaning / penetration parameters during aluminum welding.
I have not calculated the cost of the machine sitting there at idle. It may very well be cost prohibitive in terms of electric usage. If so I should be able to scrap it for about what I paid - not allowing for inflation of course.
05-20-2013, 10:03 AM #13
I doubt it will be a serious consumer at idle but I pay less than 5 cents/kwhour here.
I believe that is what unbalanced refers to so by implication (to me at least) it is discarding 1/3 of the power, 100 amps at full bore,some where other than to the work. I was not reffering to a water cooled torch, that is a given on a large machine.
05-20-2013, 11:14 AM #14
05-20-2013, 12:51 PM #15
Still, I wish I was smart enough to calculate what the per-day electric cost WOULD be for the machine to sit at idle.
05-20-2013, 01:18 PM #16