Need help identifying welder and finding parts

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Hi, first post so I'm not sure if this is the right forum or not  I'm trying to identify an old welder and possibly locate parts for it, mainly the capacitors. Its a combination MIG / TIG unit that runs off of single phase.  I do know the large capacitors sitting on the bottom floor of the welder are bad.  Also I do know the high frequency section does work.  We tested that independantly by unhooking some of the leads and powering it as a separate unit.  Any help would be greatly appreciated.Below are links to some photos of the unit.  http://www.141.com/triumphs/temp/PICT0010.JPGhttp://www.141.com/triumphs/temp/PICT0016.JPGhttp://www.141.com/triumphs/temp/PICT0019.JPGhttp://www.141.com/triumphs/temp/PICT0022.JPGhttp://www.141.com/triumphs/temp/PICT0023.JPGhttp://www.141.com/triumphs/temp/PICT0025.JPGhttp://www.141.com/triumphs/temp/PICT0026.JPGBrad
Reply:This is just a guess, but it looks like an old air products welder.  A lot of the parts look pretty generic, but have you found any part numbers or any thing that resembles a serial plate.Smithboy...if it ain't broke, you ain't tryin'.
Reply:Originally Posted by smithboyThis is just a guess, but it looks like an old air products welder.  A lot of the parts look pretty generic, but have you found any part numbers or any thing that resembles a serial plate.
Reply:Most of these older welders are pretty similar once you get underneath.  The parts inside look a lot like my miller dialarc, but the exterior doesn't look like any configuration of miller I have ever seen.  The air products line is long gone, but their parts are all pretty standard.  Actually, what makes me think that it's an air products machine is the fonts on the controls.  There is an old air products 250hf sitting idle where I work that has very similar fonts.  If you can't get to the exact make or model, you might just have to resort to building a franken-welder, snatching parts from other junkers.Smithboy...if it ain't broke, you ain't tryin'.
Reply:Originally Posted by smithboyMost of these older welders are pretty similar once you get underneath.  The parts inside look a lot like my miller dialarc, but the exterior doesn't look like any configuration of miller I have ever seen.  The air products line is long gone, but their parts are all pretty standard.  Actually, what makes me think that it's an air products machine is the fonts on the controls.  There is an old air products 250hf sitting idle where I work that has very similar fonts.  If you can't get to the exact make or model, you might just have to resort to building a franken-welder, snatching parts from other junkers.
Reply:I believe you have it.  If you can find a parts list with the basic specs, I bet most of the stuff you need will be salvagable from other welders (of any brand) of a similar vintage.  I am supposing that you probably already know that, in the end, you will probably have way more in this welder than you will ever be able to get out of it...but, projects are projects, right?Smithboy...if it ain't broke, you ain't tryin'.
Reply:Has a certain family resemblance to my old USAF surplus Harnishfager/P&H 300 amp, saturable reactor-controlled stick/tig welder, but not identical.  Similar body work and front panel style, but different layout  Same three-position, pin detented range switch.  Maybe they were all using the same style in the olden days.How did you determine that the capacitors are bad?  Those look like oil/paper/foil capacitors that are not highly prone to failure (at least, not like electrolytics).  Did you isolate them for testing?  Shorted?  Open?Looks like a basket case at first glance, and that rat's nest of wire is going to be nasty to decipher.  Don't disconnect wires without thoroughly documenting each one, first, and don't disconnect more at one time than you have to.  It is amazing how quickly you xxx I forget where a wire ran if I disconnect more than one at a time.Finding a schematic would be a great help in understanding the circuitry and wiring, but beyond that, I think it is a waste of time trying to get OEM replacement components (unless you stumble across the identical welder in even worse shape than yours).  If the selenium rectifiers are bad (but note that they will measure worse reverse leakeage and forward voltage drop than silicon rectifiers), they are easily replaced with silicon rectifiers.But the expensive stuff is there, like the main transformer, and it is probably fine.  If the main transformer is OK, and you want a big project, I'll bet you could get it running.  There's not a lot of sensitive stuff to worry about, and no electronic circuit board to troubleshoot or corrode.I recommend giving it a bath with a moderate pressure water blaster or hose and a detergent that leaves no residue.  Tektronix used to recommend that for their old tube-type oscilloscopes in need of a good cleaning and I've done it on many old electronic items.  In fact, Tek did that at their service centers.  Your unit has already had a lot of corrosion and a little more water won't make things any worse than they already are, but may make it a lot easier to work on and read information off dirty components.Look it over for any paper-based items with identification printed on them before washing it down and either bag the item or write down all the info.  There's probably not much in your welder than can't tolerate water as long as it is thoroughly dried out afterwards.  Rinse it down with a spray bottle of distilled water after the initial wash/rinse/blow dry cycle to minimize residue from hard water.  Blow dry with an air hose (dry air at moderate pressure) or a vacuum cleaner blower and let sit under a heat lamp, the sun, or other heater and a fan for a week or two to get all moisture out of the transformer windings before applying any power.  Bag or remove the fan motor and oil it.  The main risk is firing it up the welder while moisture is in the insulation, so the main thing is to dry it thoroughly and promptly after washing.By the way, what makes you believe that the welder is intended for MIG, also?  MIG normally has a different control technology from TIG.  Is there any mention of MIG on the front panel or any wire feed controller?Looks like fun, but a challenge.awright
Reply:Originally Posted by awrightHas a certain family resemblance to my old USAF surplus Harnishfager/P&H 300 amp, saturable reactor-controlled stick/tig welder, but not identical.  Similar body work and front panel style, but different layout  Same three-position, pin detented range switch.  Maybe they were all using the same style in the olden days.
Reply:Hey Awright, Bkahler, Smithboy!It's definitely a Stick/TIG or SMAW/GTAW, Constant Current only power source I also thought that it might be an old P&H machine at first but, when I read that "Smithboy" and "BKahler" came across certain similarities in the machine and the fonts used on the controls that suggested a possible match with "Air Products", I started to get even more curious!!! Linde Union Carbide (currently part of the ESAB family of Welding and cutting equipment) made power sources similar to this one in Florence, SC way back in the day!!! Just like the welding machines that were painted red for Airco which were really Miller power sources produced up in Appleton, WI... I know this because, I actually seen them made up there when I went to the Miller equipment repairman course and they gave us a tour of the plant back in 1983... I also went to the Linde - Union Carbide plant down in Florence, SC on a similar tour while in training for their equipment repair course in 1984... Then I noticed the light green worn paint on the frame which made me think of two name brands which were Linde -Union Carbide, (L-Tech was'nt even around back in those days!) and Westinghouse which also put out lean green machines with those familiar selenium rectifiers inside their older power sources... Still for some reason, my gut instinct kept telling me that it's an old P&H machine  Finally, I remembered that A.O. Smith welding equipment was made by P&H  which now makes mining equipment... When I compared the pictures to a couple of pics I found on the web, I said to myself "Awright" is correct  regarding the P&H welder similarities...  Check out some of the pics on these websites (.pdf's requiring Adobe Acrobat)http://www.fas.gov/sgp/othergov/doe/...s/00414797.pdfhttp://www.fas.gov/sgp/othergov/doe/...s/00359224.pdf Now I cannot guarantee that the machine in question is indeed an old P&H AC/DC SMA/GTA welding power source with HF but, It looks very close to the same type of frame design that P&H relied on for many years before they sold out in 1968!!! I would suggest that you send the pics of the power source in question to a company that has manuals for sale of vintage welding equipment including P&H... The website is: http://www.arcowelder.comThese folks are out in Santa Fe Springs, CATelephone:562-921-5240, Fax: 562-802-8659 E-mail: [email protected], look up in this forum's search feature for "A.O. Smith A3000"You'll find the same info on this previous thread... In fact, that's where I got the info on Arco Welder Repair Inc.  Respectfully,SSBN727"Run Silent...  Run Deep!!!
Reply:Hi SSBN727,Thanks for the reply.I think the light green paint is probably going to be the defining factor as far as who made the welder.Among other things I still haven't figured out just what vintage this welder is.  I'm betting its probably something like the mid 50s.  I'll try AWRI wednesday as you suggested.I tried the links you provided with no success so I did a google on just the file names and they came up on the Los Alamos labs website.  Looking through the 00359224.pdf file it sure does look like the same welder as shown.I spent some more time looking the welder over this afternoon.  I used a vacuum and an air gun to blow out/clean out a bunch of debris.  Looks a little better now  What purpose does the two large capacitors on the bottom serve?  If they were disconnected would something else bad happen?  I'll hopefully get a chance to put a meter across them sometime before wednesday but from what the guy told me who I bought it from he said he applied 220vac to the power main power leads and turned it on and they started to smoke.  Don't remember if he said the feeder circuit breaker tripped or not.  Any suggestions on how to check out each component would be greatly appreciated  ThanksBrad
Reply:looks like a airco that was made in the early 50'sit sure is big...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:I think I should just put a discussion of crudely testing capacitors with a multimeter in a fixed place ("Sticky" is it?), rather than repeating myself avery few threads.  How do you do that?Of course, the best test for capacitors is with a capacitance tester or a DVM with a capacitor test function.  DVMs with a capacitor test function are getting fairly common and inexpensive.  But, since few welders have them, but probably do (or should) have a basic VOM (Volt Ohm Meter) or Multimeter (same animal) or a DVM, here's a method of testing caps.A crude, but very useful test of basic health of a capacitor of fairly high capacitance value (say, 1uF or greater) is to touch your VOM or DVM leads to the isolated capacitor WHILE watch the dynamic meter indication.  If the indicator dips toward zero ohms, then climbs back up to a very high value, the capacitor is not open and is not shorted (the two likely failure modes).  The speed with which the indication climbs back up to (hopefully) infinite resistance is a rough indication of capacitance value.  Slower climb to infinite value means higher capacitance.  The ACTUAL speed of climbing is totally dependent upon your meter and the range selected.  If you want to know actual value, compare the rate of climb with a capacitor of known value. If the indication never reaches infinity, but stalls at an intermediate resistance value, the capacitor is leaky and should probably be replaced, but you have to develop judgement regarding how much leakage is acceptable for various types and values of capacitance.  You will usually see higher leakage in electrolytic capacitors (usually very high capacitance and low working voltage in an aluminum can with plastic or cardboard insulation) than in oil/paper capacitors (usually in a steel can with rolled seams, as in food cans).  High leakage may or may not interfere with the circuit function, depending upon what the capacitor is doing in the circuit, but excessive leakage current can cause internal heating and eventual failure.  Leakage is a result of partial breakdown of the insulation between capacitor plates.Inductors or transformers are a little trickier to evaluate with a multimeter.  The first test is simply determining that the windings are not open (because it shows continuity from end-to-end of each winding) and is not shorted to ground (because it shows infinite resistance from either end of each winding to the frame of the transformer or inductor).One failure mode of inductors/transformers is a winding with internally shorted turns as a result of local heating and insulation failure.  Shorted turns act like external shorts, except they may be less obvious initially and the problem may be hidden until the internal heating cause catastrophic failure with accompanying smoke and odor.  Shorted turns can be detected by testing, but not easily with a multimeter, as far as I know.  Open windings are the most common ultimate failure because shorted turns usually lead to overheating and consequent burnout.You asked what the capacitors do in the circuit.  Can you read any values off the capacitor cans?  Usually the values are printed on the sides of the cans and are often covered by the mounting clamps.Can you describe where the caps are located in the circuit?  If they are on the input lines, they would be for power factor correction, but I don't think anybody worried about that in the olden days.  If they are in series with the output leads and of fairly high value, they could be for balancing out rectification in AC TIG welding of aluminum, but that takes very high capacitance.  Could be for filtering and smoothing the DC output, but that takes high capacitance, also.  Could be part of the HV circuit, but they look awfully large for that, and it looks like the HV section caps are on the shelf with the dual air gap.  Could be for filtering/smoothing of the DC control voltage, but I don't think that's normally required for saturable reactor-controlled welders and they would probably have used electrolytics for that function.  (If only I could find the manual for my Harnishfager!)  That's all guesswork.Smoke testing should not be your first diagnostic technique.  Maybe the last, after you've inspected and tested the components.  Each cycle of overheating by smoke testing can lead to further deterioration or complete failure.  If you do choose to smoke test, get as much data from the test as possible by carefully watching for signs (or sounds) of overheating and document what you saw immediately (after turning off the power).  If you suspect any problem, feel for hot components after a short period of applied power, BUT ONLY AFTER PULLING THE PLUG OUT OF THE WALL AND AFTER DISCHARGING AND SHORTING ANY CAPACITORS.  Start by cleaning.  Then inspect each component carefully for signs of burning, corrosion, leakage, discoloration, etc.  Test each component, where possible, especially those showing signs of distress.  Feel the wires for excessive stiffness that can result from excess current.  If you find any unusually stiff stranded wires, try to find out why they may have overheated.  Look for melted insulation that oozed out of the ends of the wire.Gotta go.awright