Another convert to DC? thread.

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Hi. I tried asking about the feasibility of converting an old Harbor freight 200 amp MIG over to DC, but got no response.In short: I am wondering if my 220 volt dual mig 110 amp DC machine would make a good donor for the rectifier and other parts to convert it to DC.Does the fact that the DC machine is only 110 amps mean the parts might not be sufficient for the 200 amp machine - or, since they both are 220 input mean I might be able to take the parts from the smaller to use on the larger?Any help?Hobart Beta-Mig 2511972 Miller AEAD-200LEMiller 250 TwinNorthern Ind. Hybrid 200Longevity Stick 140Longevity Migweld 200SThermal Arc Pak 3XR
Reply:A 110-120 amp machine usually has a 180 amp rectifier assembly.A 200 amp machine would probably need a 300A rectifier to give a margin of safety.
Reply:That's what I figureOh well, I'll set it in the corner until I scrounge up the essentials.Thanks.Hobart Beta-Mig 2511972 Miller AEAD-200LEMiller 250 TwinNorthern Ind. Hybrid 200Longevity Stick 140Longevity Migweld 200SThermal Arc Pak 3XR
Reply:your asking to convert a 200A mig to dc? a mig machine is dc already? 250A or 300A rectifier for a 200A setupmig,tig,oxy,plasma,lathe,mill,bender,vise,grinder
Reply:Originally Posted by sparknessyour asking to convert a 200A mig to dc? a mig machine is dc already?
Reply:the welder is 200A AC so it will possibly  do 120-130 A DC. A  200A rectifier will fit the billmig,tig,oxy,plasma,lathe,mill,bender,vise,grinder
Reply:How much of a duty cycle do you want it to have?I went with a rectifier array on my stick welder. The array has got way more duty cycle than the transformer that powers it.Smaller more numerous rectifiers over a much larger heat sink area.old Miller spectrum 625 Lincoln SP-135 T, CO2+0.025 wireMiller model 250 and WP-18V torchCraftsman 100amp AC/DC and WP-17V torchCentury 115-004 HF arc stabilizerHome made 4 transformer spot welderHome made alternator welder
Reply:[QUOTE=mad welder 4;5010801]How much of a duty cycle do you want it to have?QUOTE]As is, it is supposed to have 40% at 150, and 20% at 200, so a rectifier array that would be compatible.Hobart Beta-Mig 2511972 Miller AEAD-200LEMiller 250 TwinNorthern Ind. Hybrid 200Longevity Stick 140Longevity Migweld 200SThermal Arc Pak 3XR
Reply:You could use 4- KBC5010 rectifiers on the cheap.  just a lot of wiring if you got the timemig,tig,oxy,plasma,lathe,mill,bender,vise,grinder
Reply:That "200 amp" rectifier looks a little light for 150 amps at 40% duty cycle or anything approaching 200 amps at any duty cycle. Just doesn't look like it has enough heat sink for that much use in a warm environment. I am sure it will hold a 200 amp load, just not for very long.I bet 2 of those would work.old Miller spectrum 625 Lincoln SP-135 T, CO2+0.025 wireMiller model 250 and WP-18V torchCraftsman 100amp AC/DC and WP-17V torchCentury 115-004 HF arc stabilizerHome made 4 transformer spot welderHome made alternator welder