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i have a lincoln squarewave 255, the machine is awesome BUT i feel the hf is a little strong and intense. i have set my spark gap to factory spec.s, but i was wondering if i were to narrow or widen the spec'd .009 gap, could i soften up the hf. i dont know if this is a silly ?. i can tig weld pretty decent, but electronics is not my strong suit. any input would be appreciated. i did a search i found plenty on spark gap, but nothing on this particular aspect of it. basically i am trying to find out if ichange the intensity like on older syncro's (but they had a dial under the bottom cover.) oits
Reply:good question..i'm thinking it would but i can be wrong..did some spark gap setting way back on a old airco..ran way better afterwards but i dont know what it exactly changed..the hobart i run has the intensity dial built in..i run it on 8 and it goes to 10..works good there.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:I am not an expert here, so consider this at your own peril...Seems like you could. The high voltage takes the easiest path or the most readily ionized path to ground. So, increasing the gap too much could potentially bring up a weak link somewhere else in the HF electrical system. It might arc to ground somewhere else that it shouldn't. Narrowing the gap will probably soften the start, but it might also make the start more difficult. You could probably safely try a smidge (i.e., a little less than a tad) at a time and see if you get the desired results without any bad side effects. I have used an oooold welder that had a HF intensity also. I suppose this is the same thing, just with a dial. Also, if I remember right from high school, the HF boxes we had had a range to gap the contacts...not just a fixed gap. Seems like the same idea applies.Smithboy...if it ain't broke, you ain't tryin'.
Reply:Speaking from general principles - not direct experience (or knowledge) - reducing the gap should reduce the intensity of the HF because the gap will break down and conduct at a lower voltage thereby reducing the magnitude of the high voltage pulses. I believe the breakdown voltage and, thus, voltage pulse magnitude, would vary pretty much linearly with gap because air has a specific volts/mil dielectric strength. So I would expect a 10% reduction in gap to result in about a 10% reduction in pulse voltage. Just a hunch.The intensity control shown on some machine schematics appears to be a variable resistor in the cable from the spark gap to the HV transformer primary. I don't know what kind of pot or insulated mounting is used that can withstand the high voltages present without arcing to ground. However, you might consider inserting very well insulated and isolated fixed resistors into your HF lead to the torch on an experimental basis until you get the feel of the HF that you want. I have no opinion on the resistance or power rating required, but in another thread ("Miller 320A/BP TIG won't arc") there has been discussion of the problems the machine owner has been having with no HF. He measured his "HF Intensity" pot as follows:"I checked the Pot again. This time I unhooked a wire so I am measuring the resistance through the pot itself. 100 = 0.0-0.3 ohms (checked it a few times)70 = 1.9 50 = 2.640 = 3.232 = 9.530 = 33620 = 2300"Be aware that this describes a problem pot, but it seems to indicate that a relatively low resistance might provide some softening of the HF. I think the high resistance measured near "20" indicates a defect, rather than intentional design. I suggest researching the schematics of some machines having an "HF Intensity" pot between the spark gap and the HF transformer primary to see what resistance range they use. I also urged the other poster to contact Miller tech support to get specs on the pot they use in the 320A/BP.If you choose this route, be sure to mount the resistor on plastic or ceramic standoffs providing clearance to other parts of the machine.Good luckawright |
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发表于 2021-8-31 23:02:26