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Up Topic Welding Industry / General Welding Discussion / AC/DC Welding Lead Problem
- - By Pacco Date 09-13-2005 14:43
I am curently doing a project for school about welding. I have been told that when using an AC/DC arc welder the leads can easily get loose and prevent an arc from being formed. I would appreciate any feedback on this subject and maybe a more detailed explanation of how exactly this happens. I have loked online and had trouble finding any articles about the problem.

Thank You,
Scitech Student
Parent - By jwright650 (*****) Date 09-13-2005 15:26
I believe the problem of loose cables stem from the heat cycling the connections go through during welding. Thermal expansion and contraction (due to this heat cycling)of the "lugs" where the cables connect become loose and the heat builds even more due to more resistance. Larger cables(less resistance) might help as they do not heat up like a smaller cable(more resistance) would. Additionally, pulling and tugging on the cables can work the lugs loose as well. (just my 2 cents)
John Wright
Parent - - By RonG (****) Date 09-13-2005 15:42
Started welding in back in 1961 to date Never seen or heard of that. At least no in the way you put it. Generaly speaking, loose connections started out that way.
Parent - By jwright650 (*****) Date 09-13-2005 16:41
Ron,
You know now that you said that, I cannot think of a single instance in our shop in the 21 years that I've been here. I've heard people talk of this, but I have yet to see it first hand. I'll bet you are right in saying that loose connections were probably loose all along.
John Wright

What are other forum user's thoughts on this?
Parent - - By Lawrence (*****) Date 09-13-2005 16:57

I believe that Ron,... who started welding the year I was born:) is essencially correct.

I've never seen solid copper fittings come loose due to expansion and contraction.

Having said that, I have seen plenty of work clamp connections become poor, where copper fibers are gripped by pressure begin to corrode and become brittle, when the connection becomes poor the electrical resistance (and heat) increase, the copper fibers become even more brittle and more of them break. Soon you have a much less efficient conductor and weld performance is affected. To an inexperienced worker this may appear like a loose connection.

How many times have you seen field service folks come in at a very high pay rate and change the work lead on a Robot or even a plain old MIG and fix a problem that was causing major rejects?

Parent - - By QCCWI (***) Date 09-13-2005 17:48
I believe a little maintanence goes a long way. If the cables were tightened to start with they stay tight unless you get that welder who is trying to weld a foot past where he/she should be welding.I have walked out of my office door many times and seen a welding cable up off of the floor with the welder on the other end pulling hard as he can trying to get a few more inches.

I do not think copper expands and contracts enough when heated to cause the cables to be loose at the welding machine. I think if you pull it hard enough in the right direction it might cause the nut to turn which eventually would cause it to be loose. But that problem is caused by the welder himself not the welding being done.

I think we need a federal law that requires a thought process take place before actions do.
Parent - By Lawrence (*****) Date 09-13-2005 18:41

Federal thought police for welding!

Perfect..... :)
Up Topic Welding Industry / General Welding Discussion / AC/DC Welding Lead Problem

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