Overheating work clamp

ekbmuts · Tue Mar 26, 2019 10:59 pm

Anyone ever have their work clamp get so hot that you can't pick it up?

Something weird going on I think. I turned the machine (PT185) on, set it to AC, 125A, 70% penetration, 30% cleaning, no pulse. Welded a short 8" long piece of 1/8" aluminum. Took about a minute. Bead came out fine, nothing unusual. Went to move the work clamp and it was so hot I dropped it. Through my gloves! The torch was also super hot.

I'll call LIncoln in the morning but any ideas???

Jon

VA-Sawyer · Wed Mar 27, 2019 12:36 am

Bad connection. Either where the wire meets the clamp, or the jaws of the clamp not making a good connection on the work. I would look real close at the connection of the ground wire to the clamp.

Mike Westbrook · Wed Mar 27, 2019 6:47 am

I constantly take and prop the clamp jaws open and wire wheel them make sure the end of the wire is clean copper and soldered to the eyelet or just soldered and the bolts tight this is especially important for mig where even dropping a volt will screw you up and of course make sure your metals clean resistance causes heat

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JayWal · Wed Mar 27, 2019 11:22 am

Is it normal for it to get warm at all? after a bit of pretty hot welding. Mine doesn't get hot but usually is kinda warm after about a half hour of welding off and on

Mike Westbrook · Wed Mar 27, 2019 11:26 am

If it gets warm it's lost amperage turned into heat may get slightly warm but a good clean contact in theory shouldn't I like the heavy duty copper and brass types first thing I do when I get a welder cut the steel one off it makes an ok fixture clamp

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cj737 · Wed Mar 27, 2019 7:55 pm

Connection of the cable to the clamp is bad, or the piece of braided copper between the jaws is possibly loose.

ekbmuts · Wed Mar 27, 2019 11:04 pm

Yeah - it was a loose connection to the clamp itself.

Man, that thing got hot!

cj737 · Thu Mar 28, 2019 5:44 am

Be glad you were only running 125a for 8”. Crank up to 250a for about an hour; you could cook a ham with it then

ekbmuts · Thu Mar 28, 2019 12:36 pm

LOL!

JayWal · Thu Mar 28, 2019 4:26 pm

i use my Lincoln 300 MP for scratch start tig occasionally. When switching back to mig i forgot to tighten the terminals when switch ground lead back to the neg post. Welded for about 2 minutes and the machine over temp kicked it. Took a bit to figure out what was wrong. First time ive ever overheated that machine usually my 50 amp breaker goes before the overtemp kicks in. Luckily i didnt fry anything.