Lincoln AC-225-S

admin

I posted this in the electrical section, but then I thought it might be better to have it here ... So, I moved it ...Hello all, I'm brand new to this forum and am hoping that some seasoned welders can give a newbie a little advice.I was just given an old Lincoln AC-225-S "tombstone".  The person that I got it from didn't have a clue if it still worked.  So, I figured that for free, I wasn't going to be out much, except my back from lifting it into my car.  My family and I live on a 10 acre farm and I have a need to do some welding to fix broken implements, fabricate some tools, and other fairly light projects.  A year ago, I bought a 110v 90amp Habor Freight flux-cored wire welder that although it's paid for itself through some simple repairs, it really is pretty much a boat anchor.Anyway, since I don't have a 50amp outlet with appropriate wiring, I went to my friends house this afternoon to see if the Lincoln welder is working.  The switch was in the off position and when I plugged it in, the outlet sparked, snapped and popped a second and then went dead.  It blew the breaker with the switch off.With an ohm meter, I can confirm that the power switch seems to be working correctly -- I have continuity across the blades with the switch on and nothing with it off.  I have no knowledge about how welders work, so that's the extent of what I tested.I've got a few questions as to what to do now.   1.  Where should I start to diagnose the problem?2.  What are the most common "diseases" with these welders?3.  Any sage advice to getting this thing up and running?Thanks a lot for any help you can provide me!!  I'm most grateful!!God bless,Chris Charles
Reply:Welcome, Charlesfarm! Thats a good old simple reliable transformer type welder. If switch was off and functional, most likely damage is an  injury to power supply cord. Conductors shorting together or to ground. Close visual Inspection or test for fault with your ohm meter.
Reply:I'll second that.I would start by inspecting the plug...is it overmolded?  If not can you dismantle it and rewire it.Closely inpect the power cord for any signs of rupture/kinking/cut/splitting or even crushing.  Just because the outside jacket looks okay, doesn't mean the conductors inside aren't shorted.With the switch off, check with a multimeter all three conductors.   Both hot conductors should measure open, and both hot conductors to ground should measure open.Be safe...just replace the cord if you have any doubt.Good luck.Ron
Reply:Thanks for the advice.  It turns out that the plug was shorting out, and there was some damage in the cord itself.I bought a new plug and rubber cord (6/3) and am replacing that.Now I have one more question ... When I hook my ohm meter from the ground clamp to the case, I get continuity.  Is this correct???  As I understand it, the welding current is to complete the path from one side of the transformer (attached to the stinger lead) and then pass through the workpiece and back through the ground clamp lead to the other side of the transformer, correct?  Does anybody know if the ground clamp lead (or workpiece lead as Lincoln likes to call it) is supposed to have continuity to the welding case?  If it's not, does this mean that the transformer is shot?  There doesn't appear to be any problems with the ground lead in terms of it shorting to the case where it passes through the front of the welder.Thanks in advance!!!God bless,Chris
Reply:Originally Posted by charlesfarmThanks for the advice.  It turns out that the plug was shorting out, and there was some damage in the cord itself.I bought a new plug and rubber cord (6/3) and am replacing that.Now I have one more question ... When I hook my ohm meter from the ground clamp to the case, I get continuity.  Is this correct???  As I understand it, the welding current is to complete the path from one side of the transformer (attached to the stinger lead) and then pass through the workpiece and back through the ground clamp lead to the other side of the transformer, correct?  Does anybody know if the ground clamp lead (or workpiece lead as Lincoln likes to call it) is supposed to have continuity to the welding case?  If it's not, does this mean that the transformer is shot?  There doesn't appear to be any problems with the ground lead in terms of it shorting to the case where it passes through the front of the welder.Thanks in advance!!!God bless,Chris
Reply:The case should be Earth Grounded.  Like the Green wire in the cord.David.Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Thanks for the help!I took the case off, and nothing is shorting.  When I measure the resistance from the ground clamp to the case the meter bounces between 40 mega-ohms and infinite.I put the thing back together and gave it a whirl.  It works and is giving me a nice arc and seems to be working properly.I'm a happy camper!!God bless,Chris