And here's an even stupider question:

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This thought just occured to me. It's probably completely stupid, since I'm at work at it's almost 6am.On a DC Electrode Positive welder...what are the actual voltages with respect to ground?Let's say it's running at...I dunno, 24 Volts. From electrode to ground clamp, you'd obviously get +24 volts. If you measured from the ground pin on the plug to the electrode, you'd get +24V as well, right?So if you weld Electrode Negative, you'd get 0V from the electode to the gound pin, and -24V from the ground pin to the clamp. (Or +24 from the clamp to the ground, if you prefer.)So, here's the question...what happens if you are welding on something that is grounded? Like, if you had to weld to something connected to a big underground copper pipe? With electrode positive, everything would work fine, but with electrode negative, wouldn't you get no current? And more to the point, wouldn't your welder short out as soon as you clamped the hot ground to the grounded workpiece?With an A/C circuit, what happens? Wwould a 24V AC circuit be balanced, i.e. swich between (-12)&(+12) at each end, or would it go from grounding one (0V) and the other being hot (+24). Sorry I don't really know how welders work...I have some decent background in electronics, but my brain isn't working right now."To tell which polarity to use go to the bathroom and pour some water down the drain. If it runs clockwise use straight polarity. If it runs counter-clockwise use reverse polarity. Or if it just gurgles use alternating current." -RandomDave
Reply:You're really trying to screw up our minds aren't you GBG.What the hell, I'll take a stab at it....what happens if you are welding on something that is grounded?
Reply:Originally Posted by mrmikeyYou're really trying to screw up our minds aren't you GBG.What the hell, I'll take a stab at it.It doesn't short out because the welding transformer isolates the input circuit from the output circuit, there's no direct electrical connection ,just thru the induced current thru the windings of the transformer, an isolation transformerI'd say from from +24 to -24 hmmmm, but aren't the actual peaks on an ac circuit higher than the indicated voltage. I thought that 110VAC had an actual peak of 170V on each crest of the sine wave.Ok, that's my stab at it....next .Damn you Skippi  it's too early in the morning......Mike
Reply:I'm not an electrician, hell I don't even pretend to be one,just have enough knowledge to be dangerous AC current usually has 3 wires: One ground, one "cold" and one hot
Reply:Originally Posted by SkippiiIf you measured from the ground pin on the plug to the electrode, you'd get +24V as well, right?
Reply:Voltages are constantly changing on a constat current machine. A machine like a bobcat it may as high as 80 volts open circuit. Voltage is always measured between the 2 poles of the source. Any other reference point is a meaningless value.Tough as nails and damn near as smart
Reply:Don’t worry about it. All is well in the universe. If anything were wrong you would have seen a bright light and your worries are over. Have another cup of Joe and a box of munchkins.
Reply:Originally Posted by tresiVoltages are constantly changing on a constat current machine. A machine like a bobcat it may as high as 80 volts open circuit. Voltage is always measured between the 2 poles of the source. Any other reference point is a meaningless value.
Reply:And you're thinkin about this at 6:00AM??? I'd say those fellows are right. I never had it happen.Don't let that iron in your lungs, turn to lead in your @$$!!!!
Reply:Originally Posted by IronmowerAnd you're thinkin about this at 6:00AM??? I'd say those fellows are right. I never had it happen.
Reply:Originally Posted by mrmikeyground, hot and neutral, the neutral is bonded to the ground at the panel only.
Reply:Zipzit, there are many possibilities, old vs. new code wiring, someone had there hands in the wiring, something broke.
Reply:For the record If you're ground Is "hot" and your torch is the ground. It won't simply short out and heat up around there.The machines sit at open circuit voltage (which is usually very low) and wait for a connection to be made to the torch or else it won't enter welding current and amperage.  grounding out is usually only a problem if the ground cable is very far away or the connection gets broken.For this reason though you can't have some one AC weld and DC weld very close together, but it's possible to have two DC welders in the same area or even on opposite sides of the same joint.
Reply:You know, once I went back to bed and got up the next day it all made perfect sense to me."To tell which polarity to use go to the bathroom and pour some water down the drain. If it runs clockwise use straight polarity. If it runs counter-clockwise use reverse polarity. Or if it just gurgles use alternating current." -RandomDave