So I tried making an inductor out of a length of welding cable and a steel core, and couldn't get the inductance high enough with the length of cable I had. I need to source some ferrite pieces to use as a core, or run a lot longer cable to get more wraps. Anyway, part 2 won't be happening until I get this sorted out, sorry to keep everyone waiting...
I wrapped 8 turns of # 4 wire through an old microwave xfmr that I cut the windings out of and it still works awesome, also a small circuit to control the spiking of the 4 - 100 amp diodes I used.I also used 2 computer power supply fans for cooling and have had no trouble welding constantly and no trouble with duty cycle.
So, what do you mean you couldn't get the inductance high enough? What does it need to be? Isn't as many wraps as you can get better than nothing at all??
In my conversion I topped out at 6 turns of 4AWG on each of two MW transformers and it still wasn't enough inductance. DCEN TIG welding using it consumed my tungsten tips too fast. I finally found a reactor with a laminated steel rod core and 22 turns on it and the DC welding is much improved. Try to find a transformer from a cheap transformer welder and use the secondary as a reactor, or possibly stack and fasten 4 MW transformer cores together and then wind 20+ turns around the entire stack on the outside.
@@CapnCrusty I was wondering if magnetic ballast HID transformers would be better since those sometimes are found for free or a decent price. I've also been wondering about making a plasma cutter, or maybe a welder, out of a digital ballast. I haven't looked at the specs of the digital ballasts yet in enough detail.
I appreciate and thank you You're doing a good job trying to explain how to get this thing a bit more linear :) I have a couple machines . Old AC/DC machines, I think the old silicone rectifiers are what they should be. What they once were ) I too am looking for ideas to smooth them out
The old "Buzz Box" looked pretty clean inside for its age. I would have thought that you might have put in a switch that would let you change from A C to D C when you wanted to use the other form of welding. There are times when A C is a better choice than D C. I do agree that most of the time you would use D C as it is a much cleaner weld.
This is amazing. Very smart and clever. I have an old big miller 300-s a/c welder. Is there something I can just buy and wire in to convert mine to D/C and A/C switchable? Thanks and thanks for the wonderful video
i think if you measure your voltage after the bridge rectifier it may be lower than if it was coming out AC. Check out the welder tag to see if it has a voltage out number and then compare to a reading after the rectifier. lower voltage= higher amps to get the same amount of work.
So if I understand this correctly, if you used JUST the bridge rectifier, you are basically making a pulsed DC welding current with a pulse rate of 50Hz or 60Hz (depending on where in the world you live). Pulse welders are the newest thing out there, although most of them allow you to vary the pulse rate. It might be nice to have the pulsed output, even if its just one set value. I have seen other guys use just the bridge rectifier on other videos. What do you think?
Inverter (pulse width) welders operate at much higher frequencies so the smoothing circuit (inductor and capacitor) is much smaller, more effective and less expensive. The term pulse being used here is incorrect and is actually just ripple. A pulse is digital, ripple is analogue. Magnetic pulsed welding is a totally different technique altogether and more mechanical than electrical.
7018 should be DCEP. That may have been why you were having problems with the arc. 6013 can be run electrode negative for welding thin metal, but I haven't tried it myself yet.
If that was like my old Fourney welder, it would have originally had plug in connections for the welder leads. They are known for failing, which probably explains why the leads are connected the way they are now.
Please,I want to change my diy ac 100amp welding machine to dc and the output is 39volt.can I go ahead with the actual bridge rectifier you used in this video?
Hi.....i got an older lincoln tombstone 225 AC welder....i'm gonna do the same thing.......also will put a reactor coil choke transformer in the output.....experiment how many turns of #0 wire on the thing....(old microwave transformer core)......thanks..
The diodes in the rectifier are carbon based and allow electricity to flow easy in one direction and very difficult in another.. so its controlling the pulse somewhat but not true dc. as I see it. correct?
mic jam correct. in order to turn it into true DC you have to smooth it out with a reactive element. Even then, you will have ripples, not perfect DC, but for a welder it doesn't matter.
Good afternoon. I have a Lincoln 225 stick welder that I did the D.C. Conversion on. The rectifier is for 300 amps. Im trying to use 7018 rods but every time I put the stick on the material I'm welding the welder bogs down and the fan stops. After I remove the stick the fan kicks back on. Im running the welder on a Coleman 5500 generator which I've used on my first buzz box with no problem but without the conversion. Would you have any idea of what's happening with me? Thank you very much. Eric.
....your voltage is probably too low. voltage, is 'pressure'....not enough will cause this. TRY placing a 5000 u Farad 200 volt capacitor across the + and + of the bridge rectifier. Google 'how to ' .......
Thank you so much. Also I went on to the Lincoln website and they mentioned some of the issues that I was going through and said after the conversion the generator may not be strong enough to power the welder.
my second response. i used a 28 microfarad one, salvaged from old junk. IT GOES MUCH BETTER, now. Arc is explosive. try an old microwave oven capacitor, about only 7 ufarads, so put 3 or 4 in parallel.....good luck.
Cannot wait for part deux, where the inductor wiring is placed to the lead ? Will you have a 4700 uf cap to smoothout the arc, can't find yet on you tube yet. Thanks
A 230 amp ac welder only puts out 140 amp in dc voltage so the amps on the machine do not translate amp per amp when going from ac to dc voltage output....
I tried this and popped a 75a circuit within seconds. I'm not convinced that this works. The rectifier I got is rated for up to 1200V 200A. It should be plenty strong enough.
I was thinking about doing this for a friend who might buy a used ac welder. Maybe I'll try harder to convince him to just buy an everlast inverter welder. I don't want to be popping any breakers.
Sebastian Adams I've tried it a few times since then without a problem, but I would still recommend spending the extra $200 to get at least a cheap AC/DC machine. I think the problem was that I was losing a little bit of power through the rectifier, so I had to turn it up 20A more than usual to keep the rod burning.
Convince him to spend time on REAL WELDING FORUMS and not just RU-vid. All the answers you seek live on Weldingweb and the Miller forums. If you are in the EU, migwelding.uk cover all processes with emphasis on EU equipment. RU-vid cannot get into the details easily covered in forums. Videos are nice for visuals but relying on them isn't a great idea. Also explore a variety of AC rods. DC is nice but AC transformer machines don't exist by accident. I like old, heavy industrial AC machines because they have higher OCV then Bubba's farm welders whose OCV is on the low side to keep gumps from electrocuting themselves. BTW many, many rectifiers have been fitted to transformer style stick machines. When the factory did it it was prettier. 6011 runs fine on AC as does 7018 AC. A common way to buy welders is a used transformer machine (tough, reliable, no circuit boards to fry) for heavier work, and a new small FCAW/MIG for thinner stock.
The three phase rectifiers are easier to com by on e-bay. Do you really need a LC filter? The aluminium plate makes little sense. You need to mount it on a heat sink with a fan. Surface area is slightly larger, but does not make for a good heat sink. Apply some heat sink compound to for better thermal conductivity.
the magnets in the shunt are weak, if you use an amp meter and a second set of hands you can adjust the the indicator but you will still have loss of range.
YES. USE A COPPER SHEET, and make several expanded wings, out in open air. even use an ac fan, connected to one of the secondaries, to run it. might be a bit slow, but, the volume of air circulating would be plenty.....
I'd like to do the same conversion on a Lincoln AC 225, and have found a source for the 200 amp bridge rectifier. Can you pls tell me the specs for the coil and capacitor? When is the second part coming? TIA garrettinbc
From what I can tell, the higher the inductance on the coil the better, but the limiting factor is space. The coil needs to be able to carry the full output current of the welder, which means the cable with which its wound needs to be the same gauge as your leads or thicker. The capacitance is less important to the functioning of the welder so you probably don't need a discrete capacitor. Part two is coming when I gather a transformer core to wind the inductor.
Thanks for the additional info. I've ordered the bridge rectifier from amazon and shoould receive it next month. Based on your comment, 8 gauge wire would be ideal for the coil. I know next to nothing about electronics, but I've watched the other pertinent RU-vid videos, including those that rewind microwave oven transformers. What I think I've learned is that the rectifier changes AC to DC but imperfectly, so the coil and capacitors each help to smooth the DC output. Boltr in Prince Rupert says that several smaller ganged capacitors are more effective than one or two larger ones.
Friction tape ("hockey tape") is actually BETTER than cheap vinyl "electrical" tape. The adhesive remains strong after long periods of time and the "cloth" part of the tape remains pliable. Yes, there are good vinyl/PVC electrical tapes out there (Scotch 33 or 88) or linerless (only sticks to itself) rubber based tapes, but they are not stocked at most hardware stores and are expensive compared to the cheap imported stuff.
Help a hillbilly out- What's the advantage of DC over AC - I inherited an old Miller AC welder my dad used for many years but I never got into welding so curious about this - My Dad used to weld / build High water tanks back in the 60's - thanks
You can use a 7018 rod with dc+ electro for much smoother welding..with dc- electro you can weld thin metal very smooth..also you can stick weld Aluminum with DC unlike AC can't..so with DC it make it easier to weld on different types of metal and thickness while using better rods to weld with..definitely worth the cost and time to have more options available..
It's not true DC , It will still have ripple , The negative cycle will show a gap as it's not there anymore , you want a large value capacitor to supply the missing cycle to reduce the ripple .
MrMadjones With a single rectifier diode the negative cycle would disappear, with a bridge rectifier like this one the negative cycle is reversed into a positive one. It's still a pulsed signal (at 120hz) until it's filtered and smoothed, but the "gap" isn't nearly as big as of you were just eliminating the negative cycle.
@@jacobinalberta thats right your just still getting a sag in current as the voltage drops to the zero cross line as you would on ac only its getting topped up again twice as often
A 200 ampere bridge rectifier on a 230 ampere welder is wrong. FWIW, going with a higher amperage for the bridge rectifier is better. Now that it's a year and a half later, I'm sure you blew up your bridge rectifier. Your only limitation is cost and physical size not electrical. The Chinese always lie about their specifications so doubling the amperage is a minimum. For example, a 230 ampere welder must have a non Chinese bridge rectifier of at least 230 amperes plus about 50-percent more power handling capability making for a minimum of 345 amperes. For Chinesium, 400 amperes would be my minimum.
The current limit of the rectifier is not an issue for me as I never run anywhere near that high. I don't need that amperage for the jobs I do so I'm fine with de-rating the welder while on DC. Lots of old ac/DC machines have a lower rating on DC. Haven't blown up the rectifier yet.
Your video is viewed by others who might be interested in a full running converted welder and not a de-rated one like your welder. If you have not physically prevented your welder from being cranked up to a higher amperage than your bridge rectifier can handle then a failure could occur. Glad to hear your mod is still running strong for you. I saw your glider video and learned that you are a pilot like myself. Stay safe.
Search on eBay for "200 amp bridge rectifier" and there should be a number of them for sale, for around $20-25 USD. You only need a 1 phase rectifier for this kind of welder, so don't get a 3 phase one.
What kind of bridge rectifier did you use I know you said 200 amp 1600 volts but what phase is it ? Would really appreciate an answer because I’m trying to do the same thing
I started messing with that recently, too. The rectifier i bought was this (works great, btw): www.ebay.com/itm/MDQ-200A-200A-1600V-Amp-Power-Module-Single-Phase-Diode-Bridge-Rectifier-Case/322872435768?hash=item4b2cb26438:g:K64AAOSwkLhaBDw0
dc wires do not go to the primary on transformer you cannot transform dc ac source goes in the primary and out the secondary and is still ac then ac is rectified to dc and out to your welding leads
hi mic fron mexico i have a question im using miller dialarc 250 stic with my wire feeder as mig welder but the problem is when i turn it on the wire is hot all the time .could i put him electric coil to control it with the switch on the gun and where to put it anyone have any idea how to do it or if there is a better solution please help thank you
Hello Mic,You could put a solenoid on the connection to your wire feeder so that you could turn current on only when the wire feed is on. You have to make sure the solenoid is rated to handle greater than 250 Amp DC, so it would be quite big. That being said, my MIG welder has a hot wire any time it is on and I never really found it to be an issue. Just treat the end of the gun the same as you do a live stick welder and don't touch it to anything until you are ready to weld.
If you're putting in a capacitor, make sure it is rated at least 50% more than the peak open circuit voltage. For example, my welder has about 80 V A/C (RMS) when open circuit, which means the peak is about 112V. I would want a capacitor rated to at least 160 V.
the current will drop after the bridge diode. if you put capacitor on it. it will charge and discharge while on welding. i tried it already. not advisable to convert it to dc welder. useless.
