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Up Topic Welding Industry / General Welding Discussion / Paging all welding machine repairmen.....(FCAW question)
- - By jwright650 (*****) Date 12-02-2008 16:06
We have a Lincoln CV655 with a LN-9 that acts up on occasion. The thing that aggrivates me about this machine is that at times (say 15 out of 100 starts) it will gouge out a huge hole when you begin to make a pass. As soon as you trigger it a splash of metal flies out where the wire was touching leaving a huge hole to have to stop and fill. The thing is that it isn't consistant. At first I thought maybe the welder didn't trim off the ball from the wire where he had just welded the previous pass, or that maybe the mill scale was tougher in some spots or something to make the machine ramp way up to start to melt the wire off....but these things don't seem to matter....it will do it regardless of how clean the steel or end of the wire is.

Any ideas?

CV655 power source
LN-9 feeder
3/32" diameter Fluxcore wire with 100% CO2
400amps/28volts
Parent - - By Lawrence (*****) Date 12-02-2008 17:04
Hi John

Prolly this was the first thing you checked...

But sometimes a poor connection on the work lead clamp or the work lead lug can cause inconsistant starts like you describe.....  Those old copper threads get hot and cold, then brittle... pretty soon all heck breaks loose.  Those broken bits of wire sometimes hide inside a swedge and aren't visible on a quick inspection.

Just a thought.
Parent - - By jwright650 (*****) Date 12-02-2008 18:11
Another piece that I left out of the original posting.....new Barnard 600 amp leads/gun assembly

good suggestion Lawrence. I will check the ground side of things though.....Table has a ground bolted to it, and the material is laying on the table(saw horses) but maybe it isn't getting a good ground for some reason.

Here is a picture of the table(saw horses)...and the wire feeder is directly behind the guy holding the crane pendant box
(ignore the Miller closer to the center of the pic., I have no problems with that one)

Parent - - By Jim Hughes (***) Date 12-08-2008 14:24
John,
I don't have any suggestions on your machine problems, but I would like to make a comment about the shop. I visit alot of shops, and I see alot of just the opposite of what I see in this picture. It is very encouraging to see safety shoes, hard-hats, safety glasses, ear plugs. The company that I work for puts a high value on safety and when I do a shop inspection to determine if we are going to use them for work I always look at their safety.

This is a shop that looks like they care about safety.

Thanks
Jim
Parent - - By jwright650 (*****) Date 12-08-2008 15:25
Thanks Jim for the kind words. That picture was just a quick snap shot to tell someone about one of the ways we work reduce a few decibels in the shop. A simple clamp on a light weight beam to the work table will cut several decibels when grinding on that beam. One of those stories where a simple picture of the clamp was worth a thousand words....LOL
Parent - By jrw159 (*****) Date 12-08-2008 15:44
Yes, indeed it is. :-)
Parent - By Jim Hughes (***) Date 12-09-2008 14:20
John,
that's right. I have known about that little fact every since I worked at South Texas Nuclear in their fab shop during construction. Here is another. I was teaching in a training acadamy that our company puts on for QA/QC managers, and we were talking about structural steel. Someone in the class brought up how hard it is to grind galvanized steel. I mentioned how if you use bees wax on the area that you are grinding on then you won't have a problem. Everyone in the class looked at me like a mule looking at a new gate. :) I thought it was standard knowledge. It just goes to show you that necessity is the mother of invention.
Sorry. That stills has nothing to do with your issue. :)

Jim
Parent - - By KSellon (****) Date 12-10-2008 14:09
Good Morning John- by now someone has already come up with an answer for your problem-- if not let me know and I will give you a couple things--
Parent - By jwright650 (*****) Date 12-10-2008 14:44
Nope, not yet...this has been ongoing now for quite awhile...the welder just has learned to live with it....LOL
Parent - By aevald (*****) Date 12-02-2008 17:40
Hello John, besides the great suggestion from Lawrence, you might want to take a close look at the contactor plates in the feeder. Along a similar vein, you could have intermittent connection of the current that could possibly have the effect you are experiencing. There is also a possibility that the pot on the circuit board that controls run-in could be having some problems. You may need to take it into your service people to have them check out some of the more than ordinary problems that Lawrence and I have covered. As the old saying goes, basics first and if that doesn't solve the problem then get the service people involved. Good luck and best regards, Allan
Parent - - By sbcmweb (****) Date 12-02-2008 18:05
I sent you a PM John. Steve.
Parent - - By jwright650 (*****) Date 12-02-2008 18:12
Thanks Steve, I will go check the PM...
Parent - - By MDG Custom Weld (***) Date 12-02-2008 21:27
John,
We had a similar problem when the main contactor was failing, now this was a CC machine and not a CV.  The magnetic contactor was not being fully engaged and it would cause the machine to ramp up the output to compensate for the lack of power.  Right at the moment when the power supply would start to ramp up the output the contactor would fully close and a drastic arc strike would occur.  Upon listening to the machine you could hear the contactor buzz and pop when the current passed.  When we removed the contactor it was pitted, arced up, and carbon was everywhere.  Replaced it and whollla problem was gone.
Mark
Parent - - By sbcmweb (****) Date 12-02-2008 21:30
Never thought of that!!

How are you Mark!! :-) S.W.
Parent - By MDG Custom Weld (***) Date 12-02-2008 21:31
Good Steve, how bout you?
Sorry for the de-rail John, it won't last too long.
Parent - - By jwright650 (*****) Date 12-03-2008 01:22
I'll have to pull the cover and take a look. I wasn't aware that these machines had mechanical contactors, I just assumed it was all electronic these days.

Thanks for the replies guys....
Parent - - By MDG Custom Weld (***) Date 12-03-2008 12:02
And it may just be all electronic on the CV, I was not sure of the machine vintage.  Ours was late 80's.
Parent - - By jwright650 (*****) Date 12-03-2008 12:17
I'll try to look at the numders on the tag and see what year the machine was built....I'll post back when I get that info.
Parent - By jwright650 (*****) Date 12-03-2008 12:22
A new one is all solid state...(contactors).... http://www.mylincolnelectric.com/Catalog/equipmentdatasheet.aspx?p=2530

....now I need to figure out from the serial# what year this one is that we have.
Parent - - By jwright650 (*****) Date 12-03-2008 12:36
OK by this.... http://content.lincolnelectric.com/pdfs/knowledge/Age_of_Machine.pdf

....the machine was built in April of 1999.
Parent - - By MDG Custom Weld (***) Date 12-03-2008 13:56
Solid state either work or they don't, so I guess my suggestion would not apply this time :)
Parent - - By jwright650 (*****) Date 12-03-2008 14:03
We have a Miller Dimension 652 that does something similar but it is no where as bad as this machine...this machine will blow a hole through a 1/2" thick web of a beam with just the pop of a trigger...LOL, that ruins your day when you were just trying to place a fillet weld around a clip angle. I would love to fix it "before" the welder(the guy in the pic above) takes a sledgehammer to it.
Parent - By Lawrence (*****) Date 12-03-2008 14:56
John,

When you find your solution please tell us about it...  This is an interesting problem (from the outside perspective)
Parent - By scott hutchinson Date 12-08-2008 06:40 Edited 12-09-2008 04:47
I may know what the problem is from the way he described it. He says the metal blows out "where the wire was touching".

The best practice is to not touch the wire to the work, but let it feed in and touch. Hold the wire at least 1/8" off the work and let it feed into the work when you pull the trigger.

I'm an electric welding machine repair tech, it's late at night and I can't think right now how to best explain why or how this will help, but I've seen this problem before,
and I'm betting that will solve your intermittent problem with this electronic control machine.
Up Topic Welding Industry / General Welding Discussion / Paging all welding machine repairmen.....(FCAW question)

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