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SOLVED! Lincoln idealarc 250-250 outputting half voltage!

Posted: Thu Aug 08, 2013 5:10 am
by Hobbyguy84
Firstly, let me thank you for taking the time and energy to help me with troubleshooting.

On my first foray into welding I bought a china machine and ran it at the rated 100% duty cycle load (140A), but it died after about 30 feet of beads (splashes). Then I thought I'd buy a real welder and not have any problems, but alas, problem. :?
It's outputting 37.5 volts when it says it should be outputting 72 volts. The buzzing is really loud. 87 dB or so. And the first time I flipped the power switch, there was a bright light on the inside of the unit. That light never occurred again.
I used the unit before I bought it, so I thought it would work just fine...

I actually paid twice in materials to set up a 50 amp outlet than I did for the welder, and it's been quite a hassle hooking it all up and transporting the unit from 60 miles north.
Since I installed the outlet and I understand it'll be met with skepticism, then I should talk about my wiring: It's a 3 prong. I hooked up the vertical prongs to red and black, and the center rounded prong to neutral, not ground. it reads 245 volts between the vertical prongs, and 122.5 volts between neutral and the other prongs.
Instructions for the welder wiring for "low voltage" are to have H1 and H2 attached to the power switch, and insulate H3. I've done that.
Are there any parts I should test to see if they've malfunctioned? is that spark which occurred the first time I flicked the switch indicative of a serious problem, or could it be a fluke that occurred maybe because of blown dust since its last starting?

Could a partially shattered electrically insulating washer on the ground lead terminal connection while set in DC+ mode?

Update: I'd decided to try to run a bead and see what happened.
I turned on the unit, and the buzzing noise got gradually less harsh. The noise smoothed out a bit.
When I went to run a bead with a 3/32 rod at 110 amps, it proved tough to strike anything. I got a few little sparks and the it popped my 50 amp circuit breaker. My electrical run is only 30 feet long and it's 6 gauge, so doubt that my wiring is the culprit.

Re: Help plz! Lincoln idealarc 250-250 outputting half volta

Posted: Thu Aug 08, 2013 7:46 pm
by Otto Nobedder
Have a look at:

http://www.lincolnelectric.com/assets/s ... /IM206.pdf

page 7, about a failed rectifier...
Specifically, "Rectifier Troubleshooting".

Steve S

Re: Help plz! Lincoln idealarc 250-250 outputting half volta

Posted: Fri Aug 09, 2013 2:41 am
by Hobbyguy84
Oh my gosh. I had almost no hope of rescuing a product manual. Thank you so much for both the manual and the direction

Re: Help plz! Lincoln idealarc 250-250 outputting half volta

Posted: Fri Aug 09, 2013 4:51 pm
by Hobbyguy84
Success! Thank you! There was a short circuit causing one of the diodes to activate!
The unit is outputting 80 volts in DC mode vs. the 72 it's rated at, so perhaps I did some damage. But it welds!

Re: SOLVED! Lincoln idealarc 250-250 outputting half voltage

Posted: Fri Aug 09, 2013 7:02 pm
by Otto Nobedder
Excellent!

Lincoln has put a lot of effort (and so have their fans!) to put as much information as possible on the internet, to support products invented before even the microchip.

When you consider buying ANY machine, your first step should be to search support for it. Can you find a manual? "check". Are the parts listed in the manual still available? "check"...

Glad I could help.

Steve S

Re: SOLVED! Lincoln idealarc 250-250 outputting half voltage

Posted: Fri Aug 09, 2013 7:08 pm
by Otto Nobedder
If you're getting 80 instead of 72, one of the "smoothing" capacitors may have failed or one of it's connection is open or weak. Fixing this (If it's the case) will further smooth your arc. These will be in what's described on pg. 7 as the "suppressor" curcuit.

Steve S