AC to AC/DC

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I cant really find or afford the welder I want.They are all too far away or far too expensive.The welder that most closely fits what I want is an 225/125 Lincoln tomb stone, but the DC amperage is a little low for what I want to do.I am thinking I should buy a fairly cheap but powerful 220v AC welder and DC it. And DC it right, with inductor and capacitors and such.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:If you have those kind of electrical skills it may be worth it.I don't know if I could make that work, but in your place I might try. But more likely I'd have a relative or friend pick up a used machine in a better area and just get it when I visit.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Originally Posted by mad welder 4I cant really find or afford the welder I want.They are all too far away or far too expensive.The welder that most closely fits what I want is an 225/125 Lincoln tomb stone, but the DC amperage is a little low for what I want to do.I am thinking I should buy a fairly cheap but powerful 220v AC welder and DC it. And DC it right, with inductor and capacitors and such.
Reply:Originally Posted by SuperArcI recall reading here  about someone that did the very thing you're talking about.  I believe it worked too. Just curious, what do you plan in welding over 125A DC, out of the buzz box?  I had some 7024's once and needed 140 amps.   I just switched it to AC and never looked back.  AC isn't "that bad" as some make it out to be.
Reply:I wanted to use DC for hard facing rod. Every one I have talked to tells me that hard facing with DC is a lot better. In the past I have only ever ran hard facing rods with DC and quickly realized I don't love AC that much when using more common garden variety sticks.  Originally Posted by MinnesotaDaveBut more likely I'd have a relative or friend pick up a used machine in a better area and just get it when I visit.
Reply:I'm no help when it comes to the DC conversion, but Miller's Thunderbolt AC/DC is good for 150a DC, and Hobart makes two tombstones with 160 and 200 DC amps respectively.
Reply:Originally Posted by AdvanI'm no help when it comes to the DC conversion, but Miller's Thunderbolt AC/DC is good for 150a DC, and Hobart makes two tombstones with 160 and 200 DC amps respectively.
Reply:Lincoln, Miller, Hobart and others made 250 amp AC/DC welders , the tombstone! ! Find one ,they make the buzz box 225/150 look sick.We had over100 AC transformers at one time thats what build everything during WW 2, tons of 7024 1/4,3/8 rods at 500 amps! ! Look at the shipyard picks the leads were a ft deep to the banks of. welders. We stick welded plate girders before subarc.Half the welders would not know what they were hooked to if you did not tell them. The same with rods they all work and all are stronger than the base metal.
Reply:Originally Posted by PavinsteelmanLincoln, Miller, Hobart and others made 250 amp AC/DC welders , the tombstone! ! Find one ,they make the buzz box 225/150 look sick.We had over100 AC transformers at one time thats what build everything during WW 2, tons of 7024 1/4,3/8 rods at 500 amps! ! Look at the shipyard picks the leads were a ft deep to the banks of. welders. We stick welded plate girders before subarc.Half the welders would not know what they were hooked to if you did not tell them. The same with rods they all work and all are stronger than the base metal.
Reply:Do some research before spending your money.  Something nags me. . . why are the AC/DC machines always rated the way they are?  Example - 225 amps AC / 1/2 the AC value for DC.For all the welders I have seen the DC rating is 1/2 the AC rating.I don't think you can rectify a 230 amp AC machine and have 230 amps DC.Spend time in research before you spend dollars in a project and attempt to re-invent the wheelGordie -- "I believe you understand what you think I said, but I'm not sure you realize that what you heard is not what I meant."
Reply:Looks of options and opinions here.a) If you buy a used Lincoln AC225s cheap (less than $100), can get the diodes cheap and your friend has the free inductor, that would work - maybe with that bigger inductor you may get more than 125 amps DC out of the Lincoln AC-225s.  Don't forget though, you also have to add a big ole polarity (DC+, AC. DC-) switch or else add some large output terminals - that can get expensive.  You won't get your money back going this route.b) Personally, I'd just look for a used AC/DC machine:e.g.1: I bought a couple Lincoln AC/DC 225/125 for $200 - weak on the DC though, I'd rather have about 160 amps on DC.e.g.2: I bought a couple of Montgomery Ward / Sears/ etc AC/DC 225/140 machines for about $150 - OK, not as smooth as the Lincolne.g.3: My favorite, I bought three Linde AC/DC 250/250 machines from $150 to $300 - best machine going for the weight/$$You can always get your money back going this route.Good Luck!Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-Acet
Reply:Originally Posted by Nitesky... Something nags me. . . why are the AC/DC machines always rated the way they are?  Example - 225 amps AC / 1/2 the AC value for DC.For all the welders I have seen the DC rating is 1/2 the AC rating...
Reply:Originally Posted by NiteskySomething nags me. . . why are the AC/DC machines always rated the way they are?  Example - 225 amps AC / 1/2 the AC value for DC.
Reply:Are you buying used off ebay? If so it may make sense. Otherwise, instead of ebay, use digikey. They have a complete lineup of semiconductors and heat sinks (Or you could make your own) with proper specs etc listed.My old 300A has an open circuit voltage of 107VDC, and an open circuit AC voltage of 96VRMS. This drops quite a bit when the current starts flowing of course.A couple of things I've learned...my old cc machine don't have caps on the output, just a big inductor. There is no need as the the cap is a voltage regulation device, not a current reg device.Constant current is a total misnomer. It's more like constant power output. On my machine at least, there is no current feedback into the mag amp control system, so there is no way for the current to be constant. IOW, your buzz box (Which is probably a physical variant on a saturable reactor/mag amp setup) should work fine with a rectifier and inductor attached.Chay
Reply:I went out of town this weekend and the perfect welder was listed and sold on craigs list in my town. A Hobart stickmate LX for $250. Nothing I could do about it. It was there and then it was gone just like that. I have been looking for months and that was by far the best welder for what I want to do that has been listed so far. Originally Posted by Nitesky Do some research before spending your money.  Something nags me. . . why are the AC/DC machines always rated the way they are?  Example - 225 amps AC / 1/2 the AC value for DC.
Reply:Originally Posted by mad welder 4I believe they use a single diode and half wave rectify the AC into quite literally half *** DC. I hear its not much better than AC.
Reply:Originally Posted by joshuabardwellI don't think that's right. Every transformer welder I have seen has a full wave rectifier bridge.
Reply:The voltage value is actually higher than the AC RMS value for a full wave rectifier. In other words, if you had a 1 volt AC secondary that you full wave rectified, and had no load on, the voltage would be sqrt(2)*1V = 1.41VDC. If the secondary was center tapped (unlikely) the DC voltage would be about 70% of the AC RMS value.The current is a bit complicated. A general guideline is about 80% dc current VS AC current.Chay
Reply:Not that it matters, and this is just trivia so take it with that in mind.  Only Lincoln has  the "Tombstone".  There is the big brother tombstone that is 250 amp class machine named such because it is shaped like a tombstone.  There are also little 225ac and 225/125 acdc tombstones that are...yep you guessed it, shaped like tombstones.  Miller and hobart don't make tombstones and never have.Cracker boxes, buzz boxes, farmer's welders, arc welders, etc are the general names I have all of them called, but tombstone is only a Lincoln thing.Now don't ya feel your brain grow?  LOL
Reply:Originally Posted by miller300aThe voltage value is actually higher than the AC RMS value for a full wave rectifier. In other words, if you had a 1 volt AC secondary that you full wave rectified, and had no load on, the voltage would be sqrt(2)*1V = 1.41VDC. If the secondary was center tapped (unlikely) the DC voltage would be about 70% of the AC RMS value.The current is a bit complicated. A general guideline is about 80% dc current VS AC current.Chay
Reply:Originally Posted by miller300aThe voltage value is actually higher than the AC RMS value for a full wave rectifier. In other words, if you had a 1 volt AC secondary that you full wave rectified, and had no load on, the voltage would be sqrt(2)*1V = 1.41VDC. If the secondary was center tapped (unlikely) the DC voltage would be about 70% of the AC RMS value.The current is a bit complicated. A general guideline is about 80% dc current VS AC current.Chay
Reply:Originally Posted by 7A749Personally, I would be patient & keep looking.There are several older machines that will do a fine job for you on a 50 amp 230 volt breaker.Miller Thunderbolt AC/DCHobart Stickmate...Lincoln Idealarc 250Miller Dialarc 250Miller Two Fifty TwinPlus a variety of machines made by or under such names as Union Carbide, AO Smith, Westinghouse, Forney and so forth. The Linde machines Rick V has posted about are very nice & can be found dirt cheap too.Adding a home made rectifier to an AC machine isn't impossible, but frankly for what used machinery is selling for now, I would use a search engine such as search tempest for CL & start looking. You're bound to find something. You may have to drive to get it, but I guarantee you that you'll find something if you do some looking aroundIMHO of course
Reply:Originally Posted by mad welder 4... I would love to have an old Lincoln ideal arc 250... If I still lived in Virginia this would not be a problem.
Reply:Ok I bought a 230amp craftsman for $100.It welds pretty good and I am lucky it didn't electrocute me to death.It came with a 33 foot 10/3 cable which only by the grace of god didn't short to the housing, lots of conductor was exposed on both lines. I cut that off and will replace with a 6 foot 8 gauge clothes drier plug. The 33 feet of 10/3 will make a nice addition to my 220v extension cord collection. If I want to run this thing off an extension cord at full power I will use my 12/5 cable (each line is doubled 12ga with a single 12ga ground).The external wiring is in bad shape. This machine belonged to ranchers not electricians or professional welders. But I can fix it, I have the technology.The tap plugs have had it, will replace with millers.Same story with the stinger and ground clamps. I have a nice brand new 300a ground clamp (miller? maybe) in my welding collection and a stinger that's brand new too.Only problem is the stinger might only be 150 or 200 amps.So far I cleaned the dust off it and took cable cutters and snipped off the 220v cable and electrode cable off (it is burned up a little stuck in the tap).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:Some one on another thread has posted that these old craftsmans have miller taps. This is true. (unless someone swaps them out)I was able to save the old taps and add another one for the ground lead, for now I will just make a set of 12 to 15 feet long cables, new junction box and 220 outlet next to the junction box.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 welderIf your willing to drive a bit, you can go to El Paso or Albuquerque.http://elpaso.en.craigslist.org/tls/4121548823.htmlhttp://elpaso.en.craigslist.org/tls/4137261639.htmlhttp://albuquerque.craigslist.org/tls/4101436689.htmlMarkI haven't always been a nurse........Craftsman 12"x36" LatheEnco G-30B MillHobart Handler 175Lincoln WeldandPower 225 AC/DC G-7 CV/CCAdd a Foot Pedal to a Harbor Freight Chicago Electric 165A DC TIG PapaLion's Gate Build
Reply:I tried Albuquerque and called about a few machines and people were real sketchy sounding and didn't know anything about what they had, sounded like run of the mill crack heads with stolen goods.Elpaso is just too far about a 6 or 7 hour drive. I figured I would go to dallas if I was going to go that far.Aside from that I will keep a passive eye out for a tig.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:I was thinking a TIG machine & just use it as a stick welder.  Wouldn't  need any gas or a remote foot pedal either, although you would have it if you wanted it.MarkI haven't always been a nurse........Craftsman 12"x36" LatheEnco G-30B MillHobart Handler 175Lincoln WeldandPower 225 AC/DC G-7 CV/CCAdd a Foot Pedal to a Harbor Freight Chicago Electric 165A DC TIG PapaLion's Gate Build
Reply:Any one ever add ducting to help the fan better cool the transformer?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:I put a sheet metal clawing around the transformer fan and a shroud on top of that. Now instead of the fan aimlessly beating air around the inside of the enclosure it sucks air in from the top and puts a gale force wind over the transformer and blows the hot air out the bottom.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:I'm sure that shipping wouldn't be cheap from just North of Houston but this is a nice machine and does what you are looking for and then some.http://houston.craigslist.org/tls/4151840721.html
Reply:I have been watching those guys in Huston. I put a topic in the buy sell and trade forum about them not too long ago for any one that lives around Houston.If I was any where near Huston it would be mine. But its about a 10 or 12 hour drive each way as of right now and freight shipping would be a few hundred dollars and it doesn't have leads.I think this little old craftsman will work real good. I picked it up for $100, only had to drive 20 miles to get it, came with 35 feet of 10/3 and about 33+12 feet of 2ga lead cable. So I was able to get a much more powerful machine right now that can pickup the slack left by my little Mig. So far I have put about $45 fixing and used several items that were just collecting dust to make it the way I want.So far I added 2 new taps, replaced the plug on the high heat out put and added a tap to the "ground" so I can remove cables during transport, swap out the cables for different lengths as needed and switch polarity for DC.I was eventually able separate and save the seized set of connectors, which I will later reuse for the DC retro fit (they aint cheap).Miller taps were about $35 for 2 female and 1 male set of connectors.The 50 amp 6 foot long clothes drier plug I used on the input was in electrical junk collection.A 15ft long 300 amp ground cable with miller tap was in my welding junk collection.I put a new stinger from my junk collection on the old 12ft length of 2ga cable that was being used as the "ground" on this machine, with the new store bought tap.Then I spent about another $10 adding a 50 amp 220 outlet to the back of the machine.At some point soon I want to build up a set of 30 to 35 foot long welding leads, I have the cable, just need the ground clamp stinger and tap plugs and install a DC rig inside the existing machine.The main cost of the DC portion will be the inductor. I think that DC can be added for under $150 and it will be able to use the machines full power, not roughly half like we see with most smaller DC machines.Last edited by mad welder 4; 11-09-2013 at 12:59 PM.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:It was in rough shape.You can see the insolation and cover melted off the tap that was stuck in its plug. The 220v input wires were in about the same condition  Attached Imagesold 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:I found a 1/4'' thick 6''x13'' copper plate in my copper collection that weighs at least 10 maybe 15 pounds and ordered a lot of 4 aluminum heat sinks that measure 7''x3'' off ebay. That heavy clad of finned metal will act as a heat sink for ten 25 amp 200v bridge rectifiers. Which will all be cooled by a 115v fan I pulled off a big battery charger.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:Do a search on paralleling diodes. They don't necessarily just add up when it comes to current capacity."USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:I did abandoned the large single inductor idea for this very reason. I had been considering balancing rectifier output with hand wound troids going to one large single welding inductor but that was over complicating things a lot and I was running into the slight problem of large welding inductors being impossible to find at a reasonable price.I put in an ebay best offer Friday night on 16 inductors rated for 23 amps continuous resulting in a 30'C temperature increase. Each rectifier having its own inductor will balance the rectifier output with the inductors natural resistance (about 1.8 ohms) and eliminate the need for troids and large unobtanium welding inductor.Also the array of smaller inductors and rectifiers should be easier to cool when I put them on my large copper heat sinks.I figure each inductor will pass around 14 amps at 25 arc volts, and 16 of them working together should do it.I should have about $93 total (including shipping) in the large finned aluminum heat sink 4pack, 16 inductors on clearance, 16 rectifiers on sale rated for 400v at 25amp and the first 440v 100uf motor run capacitor, one of several I will need to correct the power factor.Today I also wired up the transformer cooling fan with a 2 amp circuit breaker (C/O my junk collection) for safety and so I can run the fan to cool the transformer while deenergized. I figure the transformer will cool faster with no power going to it. The machine was wired so that the fan would run when the main switch is on and the transformer energized.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:Interesting approach with the multiple inductors."USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:I repowered it with a 50 amp clothes drier cord, 6 feet long 8ga. I soldered the clothes dryer cord wires to the machines existing welders 8ga wires and electrical taped them. As you can see I used a conduit clamp to relieve shearing stress from the three 1/2 inch NM connectors on the big handy box. These NM clamps are only meant to relieve tension from the electrical connections, they don't do so well against shearing.All that replaced the 35 foot long 10/3 which I now think is actually 12/3 after a second look. That 12/3 cord was connected to the machines wiring with wire nuts and housed inside a rusty light fixture box and there was nothing to stop the wires from being pulled out of the machine. You can see the ducting I added around the fan, it increases air flow over the transformer by a lot. I also wired in a circuit breaker to run the fan while the transformer is off.I also added a 220v 50 amp receptacle to the back and I may soon add a 110v receptacle, after I find a 15 or 20 amp push button circuit breaker in my junk collection. I don't want a 110 volt receptacle on a 60 amp breaker.  Attached Imagesold 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:I added a motor run capacitor to try and correct the power factor. A fan with heat sinks for the first array of 9 rectifiers (3 shown). Attached Imagesold 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:The first 9 rectifiers are installed, the inductors I ordered came in. If all goes well this week I could be testing my DC rig this week or early next week.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:How many of these should I use? A few of these should give the DC side of the house a nice little kick start.I am thinking about using 2 of them. I have around 56 of them. I did a quick search for welding capacitors on ebay and found some 50 volt 11,000 uf caps likely for a mig.Is 10,000 to 12,000 uf normal for all DC welders or is it a mig thing?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:Mig thing
Reply:Originally Posted by mad welder 4How many of these should I use? A few of these should give the DC side of the house a nice little kick start.I am thinking about using 2 of them. I have around 56 of them. I did a quick search for welding capacitors on ebay and found some 50 volt 11,000 uf caps likely for a mig.Is 10,000 to 12,000 uf normal for all DC welders or is it a mig thing?
Reply:I barrowed the non polarized 100uf motor run cap I had installed on the switch to line side in my arc welder to run a PFC test on my air compressor and discovered I it was dead. So I have no PFC input capacitor as of now.I retro fitted resistive snubers, aka incandescent panel lights into my welder on the transformer side of the switch today and will install MOVs when they come in to protect the next PFC capacitors I install.Strange thing is the transformer hums more with the twin line to neutral resistive sunubers installed (aka two 120v incandescent lights wired L to N)... I don't know why.The original AC components get much more air flow with my ducting. I did not show the blocking duct in the pic. It goes on top of the housing intake, it only allows fresh air to be drawn in through the top and hot blown out the bottom. The original design just let the fan beat a mix of warmed and fresh air around inside the housing. The only AC components were the fan its self, transformer, mains switch and variable transformer winding selector. Straight up AC welders are about as simple as killing a snake with a shovel.My before and after tests with the fan ducting show greatly improved air flow over the important parts.Now I can add 12volt fans where needed, I installed a 12 power supply for them.According to the calculation I ran I only need around 260uf to bring the PF from .73 up to .95PF. I will likely only run 200uf max.I installed two 400v 3900uf polarized electrolytic caps I had laying around after the bridge rectifier on the outputs of my welder. If I need to I can reduce it to one 3900uf cap.OCV is rated around 77VAC max, that will make peak sine wave voltage and  DCV around 106v. So 50v caps are out of the question, unless I series them up, which would yield 1/x of the original capacitance values.Phase 1 of the AC to DC conversion is about 75% complete and the AC side has remained fully functional.Phase 2 will add 4 more bridge rectifiers on a heat sink with inductors and 12v fan.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:Originally Posted by mad welder 4It was in rough shape.You can see the insolation and cover melted off the tap that was stuck in its plug. The 220v input wires were in about the same condition
Reply:As suggested, more caps = better voltage filtering.I got lucky and scored a box full of used, but good 500V 2500uf caps...like 10 of them.I'm thinking of making a seperate box and adding them when I use my voltage sensing wire feed al mig...it may make it good enough to get good results without going to a full CV setup like yours. There is still no feedback though...so the CV is a better route for sure.Chay
Reply:Again, the high value capacitors will not work on a stick machine.  Smaw is a constant current process.  Meaning the amperage stays somewhat stable and the voltage varies alot while welding. The high value capactiors are used in MIG.  I played around with this( 1000uf and higher) extensively a few years ago when I converted my AC225S to dc. It is very hard to start a rod because the instantaneous peak current is huge. And if you do you will not maintain arc for very long.  A 30uf AC capacitor before the bridge and around a 30uf dc capacitor post rectification is all you want.  I think pfc capacitor is probably little large as well.  IIRC it is better have a lagging sine wave.Last edited by kald; 11-27-2013 at 01:14 AM.
Reply:Ok I will try and find a much smaller DC output capacitor.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:Well, I need to try it before really commenting, but anything that will regulate the voltage to some extent would be an advantage, even on a constant current welder. Keep in mind this is for MIG only.The high current spike delivered will not work great for stick, but will start the wire burning rather than sticking in a MIG application.Power factor correction capacitor sizing will depend on the amount of vars consumed at the moment and will have to do with the transformer construction and the welder's loading on a instantaneous basis. There is not really not much use in worrying about this. You pay for watts, not volt-amps, so it's not going to save you any money. The ideal power factor, 100%, occurs when the voltage and current are in phase, ie, 0 degrees displaced from one another.For stick DC, you want CC (IE: a big inductor)  for sure. For MIG, the more caps the better, and very little inductance required.Chay
Reply:I want to hook this to a generator and use it. If I can use less than 50 amps of 220v as opposed to 55+ amps at full power and that can be the difference between it being able to run or not run at certain settings on various generators.On input power I think I will run a 50uf cap full time and run another 100uf or so on switches. To bring the PF from .73 to .95 would take about 260uf of reactive capacitance.I would be good with a roughly.9 PF.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