MIG gun stays hot after trigger is released

[FastKat]

I have a Lincoln Ideal-Arc SP-200 MIG welder. It's been sitting for a while, and I finally got the wire to feed reliably without birdnesting at the feeder. Well, there is a new problem...

After welding, the gun stays "hot." In other words, when you take your finger off the trigger, the the wire stops feeding but there is still current to the wire... enough current to weld. If you switch the welder off, there is STILL enough power at the wire to weld. The only way to shut down power to the wire is to unplug the welder.

Of course, this is something I want to fix. You can limp by with the gun always hot, but it's really not safe. Any suggestions? I am thinking a relay somewhere... probably a very big relay. Has anyone had this problem before? Any idea where to get parts? (I haven't had a chance to look at it yet - all of this happened when my brother was using it.)

 

[rlitman]

Many MIG units work this way. The price of a contactor to do what you want would probably be more than you want to spend, and I cannot imagine how you could fit it in your machine's case.

 

[FastKat]

So there's nothing wrong with it - it's supposed to be hot all the time until it's unplugged? What's strange... I think I would have noticed it. After welding, I'll usually switch the machine off and cut off the "droplet" of steel at the end of the wire. Wouldn't that have shocked me?

No idea what a contactor is, but if it involves adding something big and expensive to the machine, I don't want to do it!

Many MIG units work this way. The price of a contactor to do what you want would probably be more than you want to spend, and I cannot imagine how you could fit it in your machine's case.

 

[purplezr2]

That does not seem right, My Miller doesn't stay after you let go of the trigger, seems something is wrong to me.

 

[koditten]

I don't have this problem with my Miller. This is not right.

 

[Gary S]

Read the owner's manual to see if this is the way it is built. My 120v Lincoln does not stay hot.

 

[Jamesbbh]

My lincoln 110 MIG keeps a little bit of current in the wire after trigger release but It's just residual.

 

[FastKat]

Yea, that's how my brother found it. He'd usually brush the wire against the workpiece after releasing the trigger to take the residual out of the wire, but this time, it wanted to weld!

My lincoln 110 MIG keeps a little bit of current in the wire after trigger release but It's just residual.

 

[dnroe]

I dont know my miller doesnt do that either. If you pull the trigger without touching the workpiece and then touch the wire back on the workpiece without pressing the trigger you get a small arc but usually not enough to fuse the wire any. In bright light you dont even notice it its so minimal.

 

[MoonRise]

RTFM.

Page 10, warning note that drive mech and wire are 'hot' for several seconds after releasing the gun trigger.

http://www.lincolnelectric.com/assets/servicenavigator-public/lincoln3/im312.pdf

If the unit is 'hot' all the time, then it sounds like something isn't right on the control circuit board. A quick check of the circuit description would make me think "Line Contactor 2CR" may be stuck 'closed'. If the welding voltage voltmeter -always- shows a welding voltage whenever the unit is plugged in and turned on even with the trigger not depressed and no wire feeding out, then I think the contactor is stuck. YMMV.

If the wire is always hot, then I think you have to either just 'deal' with it or get the unit fixed (DIY or repair shop).

Some wire-feed machines have the welding circuit 'hot' all the time whenever the machine is ON, others have a contactor in the circuit board that only sends power through the work-lead and the electrode (and all the things those parts touch/use) when the gun trigger is depressed or for a short amount of time afterwards. Some 'fancy' machines let you program various trigger behavior states (hold trigger=ON, release trigger=OFF; first trigger press=ON, next trigger press=OFF; etc)