Lincoln Tig 250 low stick welding output

[ztugdriver]

I’ve got a 1980s Tig 250 AC/DC machine. It’s wired properly for 208V single phase. It Tig welds fine and operates normally in the Tig welding mode. However when in stick welding mode the output even at the highest setting will barely allow me to make a bead with 3/32 6011 rod. The low output is in all ranges and all polarities. I was hoping someone might have experienced this. Thanks for your time.

 

[BT Fabrication]

is your polarity correct?

 

[ztugdriver]

I’m welding EP positive and all leads are in the correct location. As I mentioned it welds fine if I’m Tig welding just won’t put out enough amps in stock mode. Thx for responding.

 

[Homeshopblob]

Have a look at your stick welding leads. I had a curious situation where the stick lead was grounding to the welder enclosure and draining off most but not all of the power. Worked fine on TIG through the torch cable. Also spread the leads out on the floor to make sure the wrapped up leads are not acting like a big electromagnet.

 

[cyanidekid]

old welding cable can have "fretting" or "fretting corrosion" inside the insulation that reduces the effective cross sectional area of the lead. l had a set that felt fine, but a load test revealed a problem and opening the 2/0 lead near the electrode holder, it was just powder for the first 4-5". this can do what you are experiencing. do you have a neighbor or buddy with leads that plug in to your welder? try a known set.

energy loss is heat loss, so a load test will also reveal what's getting hot, thus where your loss is. a load bank is the conventional test.
auto shops sometimes have load banks to test batteries and chargers, but you can also rig something up with old kiln elements in parallel. Ohms law will tell you what resistance you are looking for. use appropriate caution and good luck. let us know.

 

[gustafson]

Figure if it is shorting or frayed and too small an effective conductor, it is going to create heat one way of another so find the hot thing....

 

[ztugdriver]

Thank you all for the suggestions. I will try them out and post the results. FYI I opened up the unit and didn’t see any obvious issue. Bad lead’s definitely sound plausible as there is really no difference in how the machine operates in either tig or stick other than how the contractor is controlled. At least as far as I can tell. Thanks again

 

[ztugdriver]

Ok so changing the leads to known good ones didn’t help. I’m now wondering even though I can weld using tig I wonder if I’m getting the amperage I think I am. I’m going to throw a clamp on amp meter on the leads and see what I have while Tig welding and stick welding. If it’s way off compared to the selector switch on panel would any of you know what to look at next. It’s wired 208v and the connections are correct on the welder checked multiple times. It’s on a 200 amp breaker so no issue with enough input amps being available.

 

[ztugdriver]

After testing with an amp meter I have 260 amp when Tig welding and on 60 tops when stick welding both on high range. Anyone have any ideas? Thx

 

[gustafson]

What is the difference between the two modes? On my kinda all in one Lincoln, it would be the exterior terminals and some internal wiring in addition to the leads. If you have resistance, you have heat.

 

[ztugdriver]

When in stick mode the main contractor is closed all the time. When you switch the toggle to Tig mode on the front panel the main contractor is opened and only closes when you depress the foot pedal to start an arc. There is no changing of leads or wires. Other than that it’s just polarity selection and I made sure to test while in the same E- or E+. No matter what polarity I don’t get the full amperage when I’m stick mode.

 

[Homeshopblob]

I’ve got a 1980s Tig 250 AC/DC machine.

Is this a Lincoln TIG 250/250? I have one, bought used decades ago, troublefree for decades, real workhorse. It started acting real odd, couldn't figure it out, sometimes started an arc, sometimes just the HF, power was way off. Turned out to be the contacts in the contactor were worn down to nubbins and not making good contact every time, increased to sometimes not at all. No parts available from Lincoln, no replacement contacts available anymore. I figured out what brand of contactor it was by searching google images and bought a NOS replacement on Ebay. Works like brand new ever since.
Might be time to take the top off and watch what is happening inside when you run it.

 

[ztugdriver]

Is this a Lincoln TIG 250/250? I have one, bought used decades ago, troublefree for decades, real workhorse. It started acting real odd, couldn't figure it out, sometimes started an arc, sometimes just the HF, power was way off. Turned out to be the contacts in the contactor were worn down to nubbins and not making good contact every time, increased to sometimes not at all. No parts available from Lincoln, no replacement contacts available anymore. I figured out what brand of contactor it was by searching google images and bought a NOS replacement on Ebay. Works like brand new ever since.
Might be time to take the top off and watch what is happening inside when you run it.

It’s is a IdealArc Tig 250/250. I should have mentioned it but I did check the contacts and they did have some wear but but nothing major. I cleaned them up best I could anyway. If they were bad I’m sure I would have low output in either mode. I only have low output in stock mode.

 

[amaranth]

Looking at the wiring diagram in the back of the manual, the stick and tig electrodes are tied to the same point, the only difference in tig is the high frequency.

So if they're tied to the same point and you get full current at the tig electrode and little at the stick, it must be somewhere from the terminal in the machine to the stinger. Get an ohmmeter and check it out. Just because something looks ok doesn't mean it is. It could also be the terminal in the machine. Somewhere where the two paths diverge is the problem. You should see essentially 0 ohm between the terminal and the stinger, although I wouldn't be surprised if you see 2 or 3 ohms from terminal to stinger to drop 200A

Another thought: measure the resistance between the tig electrode and the stinger. It should be 0 or near enough.

 

[ztugdriver]

Ok first thank you for all of your support. Sometimes just talking about it makes things come to mind. I figured out what the issue was. As I mainly Tig weld with this machine I never thought to change the current control from remote to machine. I had full amperage in Tig mode but only 60 amps in stick. Once I flipped the switch to machine control on panel I’m back up to full power in stick mode. I obviously over thought this issue. Thanks again for all the help.

 

[BT Fabrication]

id be suspect of the selector switch, judging by the diagram, the current goes through the transformer, then the arc polarity switch, then the power rectifier, there are a few different paths it will take when switching things around from stick to tig mode
there is also the rectifier overload thermostat that could be stuck open.
always possible that one of the diodes internally in the rectifier have died on the stick side, and you are only getting half wave rectification so 250/2 and it inputs the thermostat half way so half that again and you are about 60A when you divide 250A by 4

 

[Graham Gott]

Ok first thank you for all of your support. Sometimes just talking about it makes things come to mind. I figured out what the issue was. As I mainly Tig weld with this machine I never thought to change the current control from remote to machine. I had full amperage in Tig mode but only 60 amps in stick. Once I flipped the switch to machine control on panel I’m back up to full power in stick mode. I obviously over thought this issue. Thanks again for all the help.

I've been burned by that one on my Precision TIG once or twice. Also had the switch on the advanced control panel get stuck between "2-Step" and "4-Step" which had me scratching my head for a few minutes a week ago.

 

[Cole2534]

I've been burned by that one on my Precision TIG once or twice. Also had the switch on the advanced control panel get stuck between "2-Step" and "4-Step" which had me scratching my head for a few minutes a week ago.

...or accidentally activating the spot weld timer.