Good news Brian .
Thanks for sharing 
Here is an example of my welder on DCEN with the two resistors across the capacitor. The wire is Hobart E71T-11. For this weld I had perfectly prepared work that was bare clean bare metal. The pipe is galvanized. I had virtually no spatter, but two tiny bbs welding these two puffer pipes.
All I did was brush it with a wire brush.
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I was wondering where you found the parts. I looked on eBay but wasn’t sure which parts were correct. Do you have a link?
150 amp three phase bridge rectifier: It seems the design has changed. This is the link to what they sell now:
Capacitor: whatever you can find. Used will work. Look for a 50 volt 50,000 microfarad or better. Or you can get several 2.7 volt or other small capacitors and wire them in series. Here’s one
http://www.ebay.com/itm/Sprague-Powerlytic-36DE-Capacitor-25000-uF-microfarad-50-volts-DC-50VDC-NOS-Cap-/301541243284?pt=LH_DefaultDomain_0&hash=item4635423994
It’s a little small, but you could get a few cheap 10,000 microfarad capacitor and wire them in parallel:
http://www.ebay.com/itm/20pc-Rubycon-50V-10000UF-Electrolytic-Capacitor-105-C-30X41mm-NEW-/361243309414?pt=LH_DefaultDomain_0&hash=item541bc77566
These are cheap, but this particular lot has many. You should be able to find them in smaller quantities.
And for the inductor, I used bare 4 AWG copper wire and used vinyl electrical tape around it lengthwise for an insulator. The toroid core I bought:
http://www.ebay.com/itm/310839060200?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
i’m afraid that 150 amps rectifier is half wave, not full and your loosing half of the dc cycles. those 100 amps full wave work just fine, they have around 10-25% tolerance anyway.
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If that were true, and since energy is neither created nor destroyed, then where is the power going? I am not afraid I’m losing half the DC cycles, since my welder is hotter on DC than on AC.
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Would it just cycle back into the grid without any real draw, like a tv that’s turned off?
What is the difference between full wave and half wave ,is it the way the diodes are wired, not enough diodes, or just the type of diode,?
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I dig it. I am so going to do this. It is too easy you almost have to if you have a HF flux core welder.
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Hello Leroy,good luck with your mig welder mod, it should work good for the thinner metals like the barrow housing and the like. I am not sure of your knowege, be carefull with dc voltage,if it rises higher than expected could be real dangerous comeing off the caps,as DC voltage hangs on and dont let go,unlike ac that is safer, my mig welder has 6 caps,and a contious bleed resistor acrrost the caps at all times, so it pulls the high voltage down too safe level, directly after the caps serve there voltage stabilizing purpose.I had some 220 caps on my hho torch, and when i tested the caps for power,it sounded like a 22 pistol pop,zap, jolt, just glad i wasent the ground.The mig welder voltage should be under 30-40 open circuit voltage,much less dangerous, other than the caps.Let us know how it helps, i have a HF that may get the boost sometime.A bigger power fan will add more duty cycle too.
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Thanks for the input on the capacitors. I don’t dig into much without first consulting some of my friends who know better than I. My first bad experience was when I was 15 and I dug the capacitor out of a furnace fan. It got me but not too bad. Just enough to let me know what a capacitor does.
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Thats about the way i am when it comes to electric or electronics, I caint remember how i tested the cap. i think i unpluged the water torch, and hung a srewdriver with plastic handle close too the other leg when it scared the out of me. shortly after that i pulled the cap out of the circuit for model changes,and never put it back with the water torch, after testing the torch on my geo metro,it took about 8000 watts too idle the car, it was too much drag on an alternator, Any way i switched too wood gas about a year and half ago when i bought the Wayne Keith plans booklet.I did get a hell of a zap trying too make the trigger circuit work on a home made plasma cutter, that one dident make it much past my arm, though it did heat it up a bit.I am glad i bought a plasma cutter now.
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Well, I looked up what a half-wave rectifier is, and sure enough, it exists. But the thing is, that the three-phase rectifier takes the sine-wave single phase AC and converts it properly into a bouncy DC signal. So there is no need for a full-wave rectifier, thank you very much.
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Hi Brian Woodrow,have you welded with the three phase diode yet and or how good do they work, i was thinking on using them for replacements for my HF mig too, are you mounting them too the original heat sink plates,or adding different heat sinks.Happy Easter
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Hey Kevin. I have welded a lot with my welder since I made this mod last year in February. So it’s been over a year. I haven’t opened it up to change the resistors, yet, but I can open it up and take some photos if you’d like.n The three phase diode works fine with a single phase. I think it’s a bit hotter because the signal is steady and on all the time instead of on/off/on/off/on/off. Just my opinion.
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I went and bought a snap on welder that is actually made by mostly century parts, it has 6 caps with one big resistor accrost all of them on the bus bar,so i am good on the pics, good too know them diodes like you used work good.THANKS
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I have been aware of these modifications for the little HF welder but never tried them.
Yes the welds are ugly but I just thought this was because I sucked lol.
Maybe I try this then?
I have some big Diodes from an old Exide battery chargers and some oil caps kicking around.
I noticed better wire helped.
These are the kind I have, as you can see you you need a heat sink to use these ( sold separately )
http://www.ebay.com/itm/4-NOS-1N4045-DIODES-100-Volt-275-Amp-Make-full-wave-Welding-Rectifier-/111951827161?hash=item1a10d950d9:g:TwwAAOSwdU1W-tII
Add this project to the growing list
I always come back to the old stuff.
This guy is one of the most dangerous and amusing people on Youtube.
Fins blowing up watermelons also never gets old.
Be careful out there.
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I went on that salvage mission today.
Looked at the diodes and heat sinks.
Turned my nose up at them 300 amps at 250 volt.
Massive over kill 3 phase units.
Can’t use the heat sinks too large ( big as my welder ).
I could have sworn these were much smaller.
I am going to sniff around the scarp pile from something smaller ( and less rusty too )
On the other hand I saved the shunts and metering from 3 units.
You never know when you want to monitor a battery bank.
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That was a very nice mod! I did a similar mod on my little Arksen 100 flux core. Instead of the three-phase rectifier I used diodes that were leftovers from monster DC drive repairs I’ve done. Similar diodes are available on Ebay. The single diodes can be connected to a heat sink that is also the connector for the bridge output which facilitates cooling. Three phase molded bridges are usually used for applications like small wind-driven generators that use automotive alternator parts which have low-voltage cramped three-phase rectifiers that aren’t suitable for a welder because of voltage spikes and cooling problems. Large single diodes allow each diode to essentially have its own heat sink which I make from sheet metal. My heat sinks are as large as the inside of the welder will allow and I used the standard phenolic blocks as insulators. I also cut away all but an inch of the case and installed metal screens to increase cooling and enclosed the xfmr in plastic ducting with a microwave oven tube-cooling fan mounted on one end to facilitate better cooling. I’ve been using microwave cooling fans for years and they are fantastic for cooling power supplies. I got several at a local appliance recycler for free. I threw out the original cooling fan and use two microwave cooling fans, one for xfmr and one for rectifier. A friend told me that I could increase heat sink area by bending waves into the heatsink metal, but with the new cooling system the duty cycle has increased substantially. Don’t forget to use some heat sink paste. Also large single diodes allow input and output wires to be bolted directly to the diode leads. A full-wave bridge allows both sides of a single-phase supply to be routed to the correct lead. When the wave is positive the bridge routes the current to the pos lead and vice versa. The caps smooth the waveform by discharging when the voltage decreases. Inductors do the same thing for current. It’s almost as good as connecting three 12v car batteries in series and using them to weld. If you have an oscope you can tailor the caps to suit your welder. To discharge the caps when the welder is turned off, I installed a relay that opens a circuit when the welder is turned on and shorts the cap bank across the xfmr primary when the unit is turned off and the relay is deactivated. I’ve built several large battery chargers that use SCRs to clip the input wave and thereby allow for much finer adjustments of the output voltage. My next mod will be the installation of SCRs in reverse back-to-back to to allow better adjustment than the current four-setting switch, or I could put the SCRs before the switches to allow even better adjustment. A trick with older DC drives was to use neon tubes instead of diacs as SCR triggers because you can verify SCR operation by watching the tubes. A friend asked me why I didn’t just buy an inverter welder, but what fun would that be? It’s fantastic to see people doing mods instead of just throwing something away and buying something better.
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I did a similar mod to my arksen 100 amp but instead of using the three-phase rectifier I used some left-over 200 amp diodes from a DC drive repair. Each diode uses its own heat sink so the box runs very cool. I did have to add an additional level to the welder so I would have room for the big diodes. The size and weight increase isn’t very much with the box being about ten inches taller than normal… My wire drive motor was very jerky when I pulled AC from the xfmr output directly to the speed control board. My wire was jerking all over the place and I couldn’t get a good feed rate so I took a 24 volt xfmr from an old cassette player and now the feed rate is fantastic and the welds look almost as good as when I use the monster stick welder from work. Now welding with this thing almost reminds me of using the MIG from work. I’d also recommend that you buy some good Lincoln flux wire from Lowes since the stuff that came with my welder throws sparks all over the place. I also bought a box of tips from Lowes and replaced the original. On kind of a goof, I pulled the feed from the diode pack output to a piece of wood bolted to the side of the welder with the negative lead going both to the stinger and the terminals on the outside of the welder. With the neg and pos leads accessible from the outside of the welder, I added a stick welding grip just to see if I could use 6013s and I was really amazed at how well the rods burn. I read somewhere that stick welding with the flux box wouldn’t work, but for repairs around the farm or garage it works great. The sticks weld much better when I’m welding upside down where the flux tends not to penetrate very well whereas I can shove the sticks into the weld pool and get decent adhesion. With the extra room inside of the welder cabinet I have room to keep a small tube of welding rods and an extra spool of wire. Many youtube videos show that these small welders overheat and trip after just a few minutes of use, but I welded a trailer hitch under my farm truck and the box barely got hot. I cut the side louvers out of the welder and replaced them with metal screen for better airflow.
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