Voltage vs current

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I haven't managed to watch the whole thing. Travis Field, (FieldRes) has a you tube video on adjusting output on a Lincoln engine welder. He explains that the two dials are Current and voltage. I'm over simplifying, but he says the volt/amp curve is better provided by high amperage, and low voltage than the other way around. For overhead and vertical welds the puddle will stay soft longer if you use too much voltage. I don't know why it would matter which factor, voltage or amperage is in greater supply how soft the puddle is, I would expect wattage, (volts times amps) to be the most important influence in the softness of the puddle. I would have thought 300 amps @ 20 volts would be equivalent to 100amps @ 60 volts. I no longer own such a welder to try it out. How about a Bobcat? Are the two dials for controlling voltage and current? Is arc force changing voltage?An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:Maybe this has something to do with it.  Old Lincoln welding handbook about 1956."USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:Thanks, that is a great old book.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:I finally found sufficient peace with no family demanding my attention to watch the video. My interpretation of his explanation is that low voltage, high current, gives you the ability to push the electrode into the side of the joint, melting lots of filler making a molten cave. much of the energy is used to melt filler which is in turn surrounded by cooler steel. As you move away, across the joint, it quickly begins to freeze. While you push filler into a hole you are making on the other side of the joint, it finishes the freeze. You have melted less of the work piece, penetrated deeper, deposited more filler, burned out "wagon tracks", and built a shelf to pile another weave of filler on.Conversely, higher voltage, lower amperage will force you to hold longer arc length to prevent snuffing out the arc. This long arc further increases the voltage, lowering amperage. While wattage may be the same, penetration is shallower, less electrode, and more work piece metal melts. The molten puddle is bigger in surface, and shallower, with more tendency to drip. As it isn't surrounded on all sides by colder steel, freeze takes longer. This may not be deep enough to fill the edge of the earlier pass.I'm likely misinterpreting his lesson. As he doesn't comment, I would appreciate if one of you knowledgeable people would make corrections in my misunderstanding. Now, how do those of us without the luxury of a 1956 Lincoln engine welder make use of this knowledge. Wrapping leads around a piece of steel will limit both current and voltage, but most engine welders, and many plug in versions have fixed voltage.Last edited by Willie B; 01-19-2015 at 08:16 AM.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:It is my understanding that arc force (dig) adjustment effectively changes the V/A curve, or drooping characteristics, if you will.  My old Dialarc 250 doesn't have any adjustment, but the two current ranges do have different V/A curves.  A look at a random Bobcat manual shows 4 ranges with slightly different V/A curves. Here's a Miller article:  http://www.millerwelds.com/resources...lder-training/"USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder