DIY Arc Welder Using Microwave Transformer? | MOT | Failed! 

I don't have a power source to provide that much input current at the moment but it did came to my mind. But I was worried about electrical insulation breakdown better primary and secondary.

This should work but its possible that isolation can break between Secondary and primary so I would try that after I`m done with different projects I have planned with them.

@@Nematics_Lab What creator said. wire them in parallely on the primary coils and series on secondary. But also it is important to understand phase. Not only in whether to wind the new secondary clockwise or counterclockwise but also in how the primaries and secondaries attach to each other. There is an input pole and output pole on each winding. I think of it like + and - poles on batteries. Where the coil enters the core (first winding) are my positive terminals and where the coil exits the core (last winding) are the negative terminals on the primaries. Just as important as attaching the wires on the secondary coil side, the last winding on one core should be connected in series with the first winding on the next core. Finally the end of the first secondary winding in this series is your welding "ground" and the last secondary winding is the stinger. Do this all right and one of your secondary coils is wound counter clockwise against a clockwise wound primary? and who knows what happens? I had all of this right except + and - mistake on the parallel wiring of the primaries and was only reading 5 volts on 20 windings of 10 gauge wire on the secondaries(2 core system). Fixed the issue and started reading 45 volts(was expecting 36 - 40 VAC) So close enough. Another matter that everyone neglects to mention is the shunts. Leave them in or take them out? Well I look up their purpose and it says "reduce arcing" somewhere. Arc? that's things I want. 2. the shunt in a transformer built for welding can be pushed in and out with a control wheel. All the way in is low power setting. All the way out is high power. So I assume no shunt means higher power and bigger arcs. Not positive on this, as it's very hard to tell if shunts are installed on these "tutorials"

@@gantz4u I appreciate your explanation I forget that I can wire both primary in parallel and secondary in series and at the moment I don't have access to mains with voltage 240V 16A or higher so I cannot test that setup as both transformer will draw about 4-5A when in action

Also should mention the input I`m using here is 120VAC variety. This is a "stepdown transformer" design so theoretically the math is this: 120VAC at 20 Amps input. 45VAC reading at the output. Should be: 120/45=2.66*20amps = 45VAC at around 53 amps on the output theoretically I believe. Im hoping this is hot enough to cook with a 1/16" 6013 rod although I`m on the low end of this theoretical output as I was shooting for around 35V @ 70amps with these windings, which I've heard should cook a 1/16" rod just fine.

I fully agree with theory provided by gantz and want to add one more step.... The way we want to ensure polarity of output winding (through clockwise or counter clock wise) we have to ensure the polarity of input supply also to be same. Then only the output winding polarity can be determined.

@Nematic

Using lower gauge wire will reduce the number of turns at secondary thus voltage will drop but current will increase, however I need more voltage for arc welding.

He's right, a smaller size of wire will allow for a higher voltage. And restricts the amperage allowed to flow. But you will have to be careful. There can be to much resistivity to length of wire ratio and to little. I found this out when I made a 12,000 gauss electromagnet to demagentize permanent magnets. But I soon found the right length. Of course though I could only run it for 20 microseconds cooled down to 30 degrees Fahrenheit. Or it would explode. I ran it on a 125 VAC 20 amp circuit. In a MOT there is major flux leakage. The main thing that can be done is to add a very magnetic material. Possibly pure iron-silicone metal sheeting. Put it around the transformer until the flux leakage is below 100 gauss on the surface.

@@Nematics_Lab try the king of random's video on this topic

how many turns do you need to get the necessary voltage?

voltage doesnt ever neeed to be that high. around 20 volts is plenty. its the amperage you need. two mots is enough. its 90 amps for stick welding avg and two mots will do that and barely need cooling. and all this crap about mots in series nothing should be in series. secondaries in paralell and thats it

Both transformer are different so I'm not sure if it will work.

Transformer should be in working condition and higher wattage of transformer is better

@@Nematics_Lab thanks for response

Krish, transformer's primary coil should be good and we cut through the secondary anyways. Usually, in 90% cases I have observed (in over 20 MOTs), the secondary winding burns out. So, its good to go if the primary is still working. Hope that helps.

very wrong. god theres so many people giving wrong advice lol

I appreciate you mentioned it :) But You are missing that if I wind output in series and input in parallel there are chances of dielectric breakdown/impedance mismatch which can cause a big fire, so for safety reasons I didn't show it in video

@@Nematics_Lab Well there's a certain procedure to follow to keep that from happening. And I can make a video on it to explain it all if you want. As long as you keep it all in phase whether or not the output on one is 50 Hz and the other is 60 Hz. It will work. I've done it on a 123 VAC 30 amp circuit. The output can be put in series or parallel. It will just use more input power. But if done right it will have no chance of causing a fire. Trust me. I'm an experimenter I get up at 8 in the morning stay in a shop work and work and perfect my designs and projects. Then I finally get out of the shop around 1 in the morning the next day. Some people have said it can't be done, but I have proven so many people wrong by doing it and succeeding while course making it safe. So if you explain thr safe way and layout, it can be published on RU-vid.

@@Nematics_Lab Even with half the power avalible. For example you have 2 110 MOT's in series output and parallel input. It logically needs 240-250 VAC U.S.A power to run. But it can be run on 125 VAC. Or whatever the designed voltage says for one MOT. In your case it's 240 VAC. It will have less efficiency. And it gets warmer just 1 percent faster. But not by much. And not anything a little fan can't handle.

@@Nematics_Lab It's not possible for a voltage breakdown of the type of enamel and glue on the windings. Especially for the input voltage it is supplied with and is outputting. The heavy gauge is rated for at least 300 VAC. And the mains coil is rated for the 2,320 VAC - 6,000 VAC. And actually that's what its rated for. Through my many tests I am sure that you can add another 500 VAC to the wiring and it won't breakdown. There's always a safety leeway in electricity. In the end the only problems that can possibly occur is if the transformer was damaged, such as being scratched, or even chipped at all. But other than that if you're careful all the way then there isn't going to be a problem.

Thanks for all the information it was really helpful, I'm not an expect in HV so I prefer to be on safe side.

wherer are you guys getting this. 20 volts. thats it thats alll you need. the arc is amperage

90-120rs I guess so not sure

@@Nematics_Lab Thanks bro 😊😊

I do watch his videos he is great!

Yes, from your video it is very clear, as I am also his great fan

I thought about it but both transformers are different so I'm not sure if it will work. Could possibly lead to isolation breakdown.

@@Nematics_Lab see that i know about it but you could have winded both using the same wire i mean without any insulation break might be it would work i guess

Wires are not same and input impedance of both transformers are different. If you want you can try that out and let me know. Currently I have others projects on my list to do.

@@umanggandhar3899 Make sure the input of each transformer is in phase. If that is good, and your power situation is good enough then the output will be in sync. I have used a 1,380 watt 50 Hz 110 VAC MOT in series with a 1,800 watt MOT 60 Hz 110 VAC. This does work. They operate at the same frequency on output. Even though they say different frequencies.

Rohan Kuruppu sir the primary coil has 3ohms .does it work in 230 volts and 10 amps outlet?

@Dave M I've done it ...and mine worked....