Munkul
Jack of some trades, Master of none
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- 7,370
- Location
- Cumbria
I suppose I can buy that logicYour table absorbs heat better and faster than air keeping that part cooler.
I suppose I can buy that logicYour table absorbs heat better and faster than air keeping that part cooler.
Like I say, it's the handle that gets hot, not the jaws
Consider that electricity doesn't only take path of least resistance
Consider that electricity doesn't only take path of least resistance
Big flex between jaws stopped ours not a weedy little bit of braided
which is why it puzzles me, because the heat is NOT greatest where the cable is joined... my goodness, can no-one read what i've written?The heat will be greatest where the cable is joined to the clamp, point of most resistance unless you are not obeying the laws of physics
I think this was my initial error, after discounting everything else. I've always given a return clamp a "wiggle" to give it a good connection... and assumed it was grand when it's probably still micro-arcing.That's the points that is being made, you are assuming that you are connecting to a perfect conductor
Running from 300kg drums the other week experiencing poor feeding. Touched the liner, super hot.We had to redesign the big drums of wire (250 and 500KG) because the steel staples holding in the base were contacting the wire and earthing it against steel plate (maybe part of a robot). So it even happens in MIG welding.
When it was first mentioned I had to go and witness it myself as the electrical engineers wouldnt believe it could happen. They suggested it was the weather...I had to inform them that I was in the UK.
Maybe a loose bolt.Its just resistance in the clamp. Even a brand new clamp in pefect condition will get warm.
I've known them glow red.
I HEAR youYes I know... but then WHY is the free side of the handle heating MORE than the rest?
YES I know it could be heating at the pivot pin... but it's not!!!
This is what puzzles me and makes me think more eddy currents etc rather than resistance heating...
I've been around welders for long enough now to know how things are supposed to heat up
It's just yon average brass clamp, nothing special, and no braid. I've never seen a brass clamp with braid fitted and I CBA to fit some myself, not when it works perfectly well... we use the same clamps at work on the MIGs and never a poor arc start.Can we have a close-up image of the clamp?
Is the described heat distribution observed during or after a weld run? If its after the weld run, it could be that most of the heat is being generated at the clamp connection to the mill scale, making the whole clamp hot, but then drawing the heat back to the steel at the end of the weld, making the contact face end feel cooler.
Is there any braided wire, or copper sheet conductor between the two halves of the clamp? How does the current carried by the other side of the clamp get to the side connected to the earth cable?
Is it because the whole clamp is heating up but is cooler closer to the table as it's conducting heat away?which is why it puzzles me, because the heat is NOT greatest where the cable is joined... my goodness, can no-one read what i've written?
It's not difficult, in theory! It's GCSE level science! As shown by everyone else on this thread!
I think the biggest unknown is the millscale on the jig... it must be thicker on the back side than the front side, to cause any decent amount of current to come through the "higher" resistance front half of the clamp. Thus, heating the clamp through the pin and spring connection. By the way, the pin and spring themselves didn't feel too warm... but maybe that was just me.
If I grind millscale off the back side only, then in theory, almost all the current will go the easy path, and the clamp won't heat up.
I'm all done with batch work for the time being, but i'm interested (in a really sad way) to see if this is the answer to the puzzle
..,. I've never seen a brass clamp with braid fitted and I CBA to fit some myself...