Need help identifying welder and finding parts : update

Tue, 31 Aug 2021 10:05:47 GMT

go to see Welding Machine for Need help identifying welder and finding parts : update

Ok, things are progressing  I've managed to download an army maintenance/operators manual for the P&H DAR-300 welder.  Turns out this welder is pretty much the same as mine with just a few additional gauges added for easy of use.  The manual had wiring diagrams, parts layouts, etc.  Well worth the $3 I paid to download it  The two capacitors on my machine that are more than likely bad are 40 MFD power factor correction capacitors.  What I don't know is what type of capacitor and what voltage they would need to be.  I'm guessing somewhere around 400 to 600 vac capacitors.  As to what type, I haven't a clue?  Anyone know how I would determine what type and voltage the capacitors should be????I'll post more details in a few days after I've had more time to absorb the wiring diagrams.  I'm sure more questions will be forth coming.Thanks!Brad
Reply:First thing to do is determine that the capacitors are actually defective.  I recommend the technique using an ohmmeter that I described before.  Clean and dry the terminals to avoid excessive current leakage to the case before testing and putting into service.They look like paper/oil/foil capacitors, that is, two layers of foil rolled with two layers of paper, then the roll is formed into the shape of the sealed can in a press and the roll then submerged in dielectric mineral oil and sealed into the can.  The oil is actually the dielectric (insulation between plates) and the paper is the physical separator to assure a certain thickness of oil between the foil plates.  Then the whole thing is sealed into the can.I have never purchased this type and size of capacitor new.  I've gotten all mine from surplus electronics outlets.  Google "electronics surplus" and look for "oil capacitors."As always, I recommend asking the manufacturers for recommendations on component ratings.  Since your welder manufacturer is long gone, I'd ask any maker of transformer type welders what voltage rating they use for PFC capacitors.  In the absence of a recommendation from a manufacturer, you get a lot of hits googling "power factor correction capacitors."  I'd guess that some of them discuss voltage rating required.awright
Reply:Small World, Brad.  I was poking around at my local scrap yard yesterday and ran across a Harnishfager/P&H welder looking almost exactly like your project, except in showroom condition.  It is not your exact machine because it is three-phase input and DC-only output, 200 amp with HF.  Just passing this on as small-talk, because it looks like you have found the info you need.  Have photos if you want to see them, but don't really think they will be of much interest to you.awright
Reply:Brad where did you find the manual for the DAR 300? I have a DAR-300HFGW, and am looking for info. Can you also pass on part sources and any info you come across?thanksDave
Reply:Originally Posted by DaveHathBrad where did you find the manual for the DAR 300? I have a DAR-300HFGW, and am looking for info. Can you also pass on part sources and any info you come across?thanksDave
Reply:Thanks, I have to check to see if the schematic is still in place. This thing cam from a military surplus auction years ago, and sat in the corner of a garage for a few years after that. I'll let you know what I find. Thanks Again for your help
Reply:Brad,I just purchased a P&H DAR-300HFGW and could use the manual.  Can you send me a link to your website as well.thanksMatt
Reply:Matt,PM sent with link.Enjoy!Brad
Reply:Hi Brad, I just purchased a Dar-300 at an auction for 40.00 and would like to find the manual for it. My Email is [email protected] if you could send me the link allso. Thanks.DRM
Reply:Hi Brad, We have a A.O. Smith A3000HFGW that looks identical to the P&H unit.  Would also like a copy of the manual.  Our email is [email protected].  Thanks in Advance. Gary