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Well, turns out that the rectifier assembly on my Big 40 is shot... apparently something the previous owner neglected to mention when he sold it. Any ideas on a reasonable cost replacement? The PN I have is 108 205, it's the style with 7 aluminum plates about 3x6" and press fit diodes mounted between them. The manual lists it as "Rectifier, silicon, 3 phase 350 amp" Has anyone has any luck rebuilding on of these? The diodes are press in and look similar to alternator diodes, so maybe you could use those? Any thoughts? I'm trying to do this on a low budget... like everyone else. Thanks, ~John
Reply:Alternator diodes are usually 100 volt. and 40 amp.You have to know how to test the diodes first,only 1 or 2 could be shorted.Each diode has to be checked with an ohmmeter.You should see 10 ohms with the leads on one way and infinity the other way.Diodes may have individual part numbers on them so you can cross reference them..You need some one with electronic experience to help test the diodes.You will find an original part is expensive.At this point you dont know if the rectifier is bad.
Reply:Unless your time is free, your best bet is to buy a new diode block - with the proper part number.If your time is free, you can lookup the diodes and buy new or replacment ones. This require research. As for 3 phase diode bridges, you can of course find new ones and you can find new ones that will work for you.You need to know rated current, rated voltage, rated forward voltage, 3ph or 1ph, and if you need a full bridge (probably) or 1/2 bridge. Then contact Newark or similar and see if they can source you one. You want higher current ratings, higher voltage rating, _LOWER_ forward voltage (sometimes they call it max forward voltage). Max forward voltage is based on current flow. So you can guesstimate that 2.0V @ 1000A is roughly the same as 1.0V @500A. Roughly! The big rectifiers are used on things like welders and battery chargers (like fork lift battery chargers).You will save some money finding your own rectifiers. Whether its worth it depends on how long you search and what your time is worth.Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:I have all the diodes from a Miller SRH400 that I scrapped due to not having 3 phase... I think I have a thread on them in the for sale section somewhere.Tiger Sales: AHP Distributor www.tigersalesco.comAHP200x; AHP 160ST; MM350P, Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma. For Sale: Cobra Mig 250 w/ Push-pull gun. Lincoln Wirematic 250 |
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发表于 2021-8-31 23:58:14