Easiest MOT Salvage Tutorial Pt.3

Video 3 of a series showing how I disassemble Microwave Oven Transformers (MOTs). This video shows you: 1 - How to clean up the old core, 2 - How to create a bobbin to wind coils, and 3 - How to put it all together. You should be ready to make any MOT project after this.
Based on feedback, there may be a Pt.4 later, to include FAQs and things I missed or explained poorly.
Part 1: • Easiest MOT Salvage Tu...
Part 2: • Easiest MOT Salvage Tu...
Perhaps these videos will help you save money on tools or projects, or even make you a little bit of extra money off of the things you make with them. If you live in an underdeveloped country and are looking to start a business but can't afford (or even have anywhere to buy) the tools to startup but have access to junk, this is for you. If you're looking to buy nice tools later, having some trades experience with a cheap one can help you know what features you'll want.
Upcoming Projects: Spot welder, stick (arc) welder, plasma cutter, variac, hydroxy torch, carbon arc torch, arc furnace, battery welder, car (or other) battery charger and more.

[@rikkybora7895]

After watching your 3 MOT videos, I feel almost a professional in transformer rewinding. The downside, the pack-rat shall grow even more in me going ahead.

[@williamwellisch960]

Please make more videos, ignore the haters! You have a refreshing sense of humor(rare in the KZbin world). I had fun watching your vids and was disappointed there weren't more of them. Subscribed!

[@DavidColl78]

you`ve got the best teaching attitude / make-do video I`ve ever seen. Bravo ! Hope you continue this way, these MOTs were very fun to watch with 100% learning material

[@sonofsam22]

I think the wait is worth it, your videos are enjoyable, FULL of information, and just plain awesome! You've certainly earned a fan!

[@MattsAwesomeStuff]

Thank you for expressing all the things I tried to ensure I did, when I made this video. Very kind of you to take the time to say so.

[@The-Bloke]

This is hands down the best MOT tutorial I've seen, and I've just watched several. Thanks very much for this comprehensive, clear and concise guide! Sad to see you never made many more videos. Hope you didn't end up zapping yourself with 2KV or something like that :)

[@jamunizca]

Excellent video! You give a tremendous wealth of information in a short length of time. I look forward to seeing more of your videos.

[@MattsAwesomeStuff]

To some degree, yes. It will also make your volts sag more heavily under load (true of using any shunts) which is generally undesirable. Shunts don't limit current in a "leave it alone until it hits X" useful way. They muddle with it along the way. The better method is simply more primary turns. If you want one that stays cool in ambient air, use 2 primaries in series (240 turns). But note you won't have much room for 2ndary unless you replace the whole primary with thinner wire. Many options.

[@tomatohodson]

I love the sped up video and power tools sound really cool when played back like that.

[@MattsAwesomeStuff]

Thanks Nate, that's encouraging. I have many in progress but they keep not being a high enough priority to finish. I like making the actual projects, not editing videos for countless hours, so, it's hard to slow down and document things. It's such a big hurdle I've avoided even chipping away at it for a while. I'll get on it some more soon, I do want them done.

[@selador11]

Subscribed! Dude, you present tough material in a way that is easy to understand! Thank you.

[@Tocsin-Bang]

Probably the best MOT series I gave seen!

[@MattsAwesomeStuff]

Stephen Cook - it's because I was the first, everyone learned from me. Thanks for the kind words.

[@Tocsin-Bang]

Having spent most of my adult life as a teacher and a trainer, I have to say you are extremely modest. It takes skill, knowledge, planning and understanding of your audience to do this so well.

[@eagleeyes6972]

very good video with good explanation you are really good at showing and teaching great thanks and well done

[@MattsAwesomeStuff]

+Alok_Deherkar - This really deserves it's own video, I just haven't finished filming it yet. In short... you can wire the primaries in series or parallel. Both work, as long as do the correct thing with each of them depending on the solution you pick. For your situation, I would wire the primaries in parallel, but their phases must match (all heads and tails each together if coiled the same direction (clockwire/counterclockwise), reverse any that is coiled backwards). For the secondary, again, you could wrap them in parallel or series. I recommend series. So for a welder if you're looking at 30v and 3 transformers, size your wire so that you barely fit 10 turns on each core. If you voltages add wrong (10+10+10 = 10 instead of 30) then one of your secondaries was put in series backwards (10+10-10 = 10), just swap that one's head for its tail. Make sense?

[@ClevelandRocks216]

bruhhh! I watched probably close to a hundred of these types of videos. not to mention, I rewatch the good ones (like this) countless times. I came across this one today. already watched the previous 2, and I subscribed etc. when looking for that spot welder video tho..well, I cant seem to find it lol 8 years so I'm guessing you changed your mind? this is amazing content, and I love the humor. bout spit my coffee out, when you started painting your nails, in the one..thanks homie

[@dylanm36]

Very valuable set of tutorials, must have taken you a while to produce. Thanks, it's appreciated :)

[@NoxuzBlog]

dude thanks a lot this is by far one of the best videos i have ever seen... love the humor!! keep it

[@markm2302]

Awesome video ! I would love to learn more from you. Hopefully you will make more . Thank you for taking the time to help others.

[@PrinceWesterburg]

Nice editing with a sense of humour. Love the sped up footage with motion blur and in-key sound, would like to know how you did that actually! :o)

[@carlgradolph9676]

Best video I've yet seen on MOT rewinding. Pulling wire through an assembled core (as many videos recommend) makes no sense to me. Not only is it inefficient and a pain in the ass, it also poses the threat of nicking the insulation on the wire being pulled. Why not take a little extra time to disassemble the core, because after all, tearing sh*t apart is fun, right? People who have decided to tear apart a microwave oven in the first place should understand this intuitively. Taking the extra time to build a bobbin to wind the new secondary is a good idea too IMO, because building stuff is almost as much fun as tearing stuff apart. You do a good job of discussing risk factors and presenting the necessary math and physics in a bare-bones manner. Based on that, I have subscribed. Looking forward to future videos.

[@MattsAwesomeStuff]

I think many people are looking forward to future vids, but it's been 6 years and I haven't gotten off my ass to film any. Some day I may start a Patreon shame campaign where your donations make me feel worse about not making videos. I'm not sure it'll make me make more videos, but it would make me feel worse about not making them.

[@carlgradolph9676]

Matt: I've produced or crewed on hundreds of hours of video (none of it available on KZbin), so I fully understand how much time and effort goes into the process. To make a quality video, you have to have equipment: Lights, cameras, microphones, props... Plus, you need to have some kind of script, or at least some rough plan for presenting your information. Then, you gotta shoot some raw footage. A lot of it. The basic rule of thumb I was taught is that it takes one hour of raw footage to make one minute of finished product. Having shot a bunch of video, you then go through the agonizing process of editing, wherein all sorts of choices must be made (including the decision to re-shoot some scenes that didn't quite present the information in a meaningful way, or when the lighting wasn't right, or the audio dropped out, or the cat walked in front of the camera...). Few KZbin viewers are likely to understand or appreciate this. Many just want free information, and some are so lazy and stupid that as soon as they latch on to somebody like you, they expect you to design a 7000 watt power supply for their ultra-bass amplifier for free! So I support your idea to launch a Patreon channel (or whatever it's called). Can't say at present that I will fund it, but you might be surprised to find some very generous backers out there in the aethers. That's what makes the World Wide Web so exciting, right? Best of luck.

[@roberttwiss7514]

It took me a while to find the information you provided, great job, thanks.

[@CaseyNixa]

Cool! Looking forward to the spot welder video. I could use a bench top spot welder to build battery cells for RC cars.

[@redpillftw]

Awesome series! Hope to see more in the future!

[@mcyammerer2262]

Good stuff, did you make the video about the spot welders? I'm curious to know the kind of voltages that work well for welding battery tabs. I'm thinking between 2 and 5, possibly making up to 3 stages for low med and High voltage.

[@santoshmane3383]

Nice demo sir . Thanks. I want to use this 12 volts 40 amps mot power supply to my Hydrogen generater could i run it continue ? What sq.mm of wire have to use and how many turns have to wind ?

[@billybonewhacker]

this series was obviously a lot of work. and i appreciate it.i have a book called quick and dirty transformer design. which has all the math but i Never thought about using mots.i build homebrew tube sw radios and transmitters.and tubes need higher voltage.i may try this cuz formers from radio daze are like 100$!. ty

[@mindofmadness5593]

Wanted to say thanks. Funny I've torn a lot of these apart over the years. As a kid the "E" made goodthrowing stars. As an adult the wire made good salvage. I knew what a transformer is but it never came together that I was tearing one apart. It was sort of like all the Doohickies one finds on a circuit board-neat to look at but not knowing if they have any further use they get junked. Need something that walks people thru the basics of what those things are to desolder an reuse.

[@oddjobbobb]

This is a really informative series. I learned a lot about transformers generally and MOT in particular. A couple questions, although I understand I am a while behind. If I have a MOT from a 120 volt microwave oven, I can’t connect the MOT from that oven to 240 volts because it won’t have sufficient windings? 2. If I want to make a spot welder, making the secondary with one very heavy U-shaped turn is preferable to two or three less heavy turns? 3. On the secondary you turn, why do you want so much gap between the core and the outer loops of the secondary? You used a pencil width at each end, but the original secondary seems like it was very snug to the core? Is that because the original was machine made and could have closer tolerances? 4. The core of the MOT has very shape corners. Is the transformer performance diminished if, after fully dismantling the MOT the edges of the corners were softened a little bit? Thank you got this excellent YT series. Lots of help.

[@MattsAwesomeStuff]

1 - You got it. The drill motor has resistance. Amps = Volts / Resistance. So, if you give it the voltage it's designed for, and its resistance is what it is... it will use the current its designed for. If you give it more voltage, you'll get more current (it'll spin faster... you can probably cheat and get more power this way too, mostly-safely). 2 - First, when you turn AC into smoothed DC, you get 1.4x the voltage. So, 14.4 becomes 20. That's probably fine. (I screwed up this formatting...)

[@AlphaTroniks]

I have a question... Do I need to wire the primaries of two transformers in series or parallel? I am planning to use 3 transformers if 2 fall insufficient for my MOT Welder. I'm confused on the wiring. My country runs on 230/240 Volts AC... Thanks in advance!

[@smokyatgroups]

Thank you for making these videos your tips and expertise are great!

[@georgekhaziran]

Matt you got me hooked THANKS !

[@sexysallyUK18]

Thanks I enjoyed all 3 parts. Looks like a lot of people skipped parts 1 and 2, hence lots of Q's that have already been answered in the videos.

[@zubeirmohammad8262]

hey matt, i want to make a stick welder with the 'E' cores and i want to have different amperage from the secondary winding, so could help or suggest me some ideas on how to make it Thanks

[@johnconrad5487]

I watched all three parts. very well done. thanks.

[@parkerd2154]

Hey man, great video. Now time to upgrade to a real channel icon. YOU'VE EARNED IT

[@MattsAwesomeStuff]

@konstantinNeo Beryllium Oxide is only present in the tips of the magnetron CRT, and even then is touch-safe unless you grind it into powder and inhale it. It will be either pink or white and looks ceramic. Safe to handle and cut off above or below (mates to steel or copper), just don’t go grinding into the clay part. Unless you’re after the copper in the magnetron (underneath the heatsink fins) or the 22g tungsten filament there’s no reason to strip the magnetron down that far.

[@grahamchiz6076]

Best one I've seen. Thanks.

[@MattsAwesomeStuff]

Yes. ... I just did. You just watched it. Use the specs you need for your lights/fountain project, pick your low voltage, follow the procedure in this series of videos.

[@RaglansElectricBaboon]

Love it, thank you for this series. PS Did you expect to be entertaining folks in NZ 8 years after posting these videos!?

[@waltpett2364]

Clever and funny. The best video on You Tube. You should be in show business.

[@MattsAwesomeStuff]

Yes. Still making it 60% filmed. My big project is an electric bike from junk which I've filmed as well, and that's occupied both my studios (basement and garage) and it's a pain in the ass to clear everything out and set it up for a different project. The bike has taken way longer than I thought. Spot welding primer: Make a 1 turn secondary. Copper tips, clamp. Done.

[@greenalyd]

cool!!! I want to make a stick welder with two of those MOTs but its posible to make a welder with amp range? thanks!

[@tomatohodson]

@MattsAwesomeStuff I wonder if that was the compression algorithm stripping out higher frequencies or something else. As an aside: what type of currents does your one turn secondary spot welder carry, I wonder if a cast aluminum loop would make a good secondary.

[@MattsAwesomeStuff]

They are original. The laminations often have the holes if there is a jig that the helps assemble them nice and square into the transformer. Depends on the factory/process. Don't despair. Just use some epoxy, silicone or any of the other solutions I suggested. A couple wraps of tight duct tape even works fine, even though it impedes cooling and will eventually dry out and flake.

[@RileyPorter]

looking forward to your spot welder vid! Great work.

[@neonboy22]

There are many kinds of coating on wire. Which one is best for high voltage insulation ?

[@MattsAwesomeStuff]

Well that's very kind of you to take the time to say. Thank you.

[@harukoyama9515]

Thank you so much for the direct answer. I ask EBay seller the same question. They have no clue. So basically I need to purchase multiple rating amp meter for a accurate reading. Or is there a devise that will measure all current of all size accurately?

[@MattsAwesomeStuff]

Many multi-meters will have a range, or even an auto-range function to measure many ranges. I don't like autorange just because it's slower, you have to wait for it to figure out what range it's supposed to be. Most multimeters max out at something like 0.5A. Then there is a separate connection for up to 10A. Above that, you usually need a specialized meter with a calibrated shunt. Why do you need to measure current so precisely at such high currents?

[@MattsAwesomeStuff]

@tomatohodson : That's just it. I compress with "Maintain pitch" so the frequencies don't get chipmunky. And in editing it's fine. But above some speed, they mute entirely. The only fix is the opposite, let it get high pitch, then try to guess at how far to bring it back, and even then it sounds muffled. Currents: 1 amp per watt. ~1000A. I cover it in the video (scripted, so far unfilmed), cast alum is fine, but you lose 40%. So, 600A. Don't worry, there's a free copper method.

[@joeblowjohnny2297]

Hi Matt , AWESOME videos ! I was hoping you can make a 100 amp batter charger ? I didn't see anymore videos ? Thanks for reply Matt !

[@MattsAwesomeStuff]

Sorry for late reply. Yes, 100 amp battery charger is possible, but you would need a 1500 watt MOT. Also, it's only good for short term (jumping), not a walk away charger because the MOT would melt. To build a battery charger, plan on 11v output. You'll need a 100 amp FWB rectifier ($10-20) or 4 diodes to convert it to DC, and then some large capacitance to help smooth it (20v capacitors, electrolytic, at least a few thousand uF). The FWB will eat 1.4v because the path is through two diodes (each eat 0.7V), so you'll have around 9.6 volts after that, but AC's peak is 1.4x it's RMS voltage, and your battery will charge up to the peak, so, 9.6v * 1.4 = 13.4v. That's about right for a lead-acid "12v" battery. Car alternators are often set to 13.8v. To build a charger you can walk away from, you need to add almost double the turns on the primary. Shoot for the same target on the secondary. You're not going to get much for amps, maybe 20-30amps. Check it to see how hot it gets.

[@liljoey112]

hello, so I rewired a MOT for 40v output with a 25v center tap. But the primary gets extremely hot in seconds. I measured the current with no load and it draws about 10amps. is this normal?

[@selador11]

I should be able to easily use standard single strand 10 to 12 gauge romex for the secondary winding. Should be plenty of room, with lots of room to spare. And it should then carry enough amperage to keep the drill supplied. All this, I have gathered from the info you provide. And thank you very much for that. Now the questions. (Continued)

[@Tankerbuzz]

If i wanted to max output amps what turn ratio would you suggest since you cannot just put 1 in the secondary? Also could you explain the reason for this briefly. I have finished high school level physics so do know a fair amount already :)

[@Donisgr]

Thanks for the quick reply. I'm not sure if it needs something more than just to replace the secondary coil of the MOT with a thicker one copper wire and thats all. I don't need it for some special job, i just find it a very interesting project and i have 3-4 not working microwave ovens and some 150kg of cooper wires for recycling so i thought to make something usefull with them. Anyway i'll be waiting for your next videos.

[@harukoyama9515]

1. Trying to estimate how much watt a power tool is design for. So I can kind know what FWB amperage I need. Bigger the motor , bigger watt, smaller motor, less watt. The different between full wave and half wave is full is using top and bottom sin wave. While half only use one side which is also half the amp. Is this correct? The rectifier block specification sheet does not say it is full wave. Is this mean it is half wave usually? 2. After I removed compacitor, how do I know it is still good? Visually the top of cylinder cross is not buldging or black shown overheat once before? After removed it from circuit board. How do I know which side is positive and which side is negative? Or Does not matter?

[@two_number_nines]

great video man, but i see your thin core transformer which i also thought of, but after some thinking i realised that this way you overload the core, because you double the magnetic field of the primaryes, but keep the cross section the same

[@AlphaTroniks]

I'm planning to use 4 MOTs because each houses 8 turns so 8V x 4 MOTs =32/34 Volts approximately.

[@pietzeekoe]

Can't wait to see it. Subbed

[@Hobbywelder617]

So, if I use the "step-down" it will increase amperage correct?

[@MattsAwesomeStuff]

@tomatohodson : Everyone does, that's why I kept 'em. :) Trivia: Crappy thing happens if I speed up audio too fast (past about 8x) it ends up muting it to zero in compression. So, I actually had to manually manipulate the sound in an external editor to keep some of the effects. Worse, this didn't show up in preview, only the final renders, so I had to re-render every time to find out what it might sound like. Never found a fix for it, hours of playing around trying.

[@NWKEEN]

Having connected this way,the out put was 44 volts drawing 9.8 amps from the wall socket.not as so noisy after applying varnish.however,without load in less than 2 minutes the primary heats up and so does the top of the transformer coz of primary.would the 2.5mm secondary and the primary be ok with arc weld with the output amps? (each transformer connected alone is 22volts drawing 5.1 amps probably over 50amp output so over 100amps when connected parallel right?)

[@yurianhuizing2352]

i want to build a 14volt and 30amp transformer should i use a transformer like this? or a transformer from a old amp have one laying around is was from a 5x80watt amp

[@MattsAwesomeStuff]

I think that would be a perfect use of an MOT. 14x30= 420 watts. That's a small MOT which means you have room for extra turns on the primary to help it stay cool. However, your audio amp will be wound with more turns on the primary right from the start, so, same difference either way. What are you making?

[@MattsAwesomeStuff]

Thanks, that's very kind of you to say.

[@tabhorian]

I'm making a stick welder. One guy makes a "Scaryac" to modulate the power going into the primary. That really does scare me. I have heard that wrapping a coil around a core and then moving the core in and out of the coil will vary the power. How does that work, and how do you do it?

[@MattsAwesomeStuff]

I agree. That's why... I did exactly what you describe. Did you watch Part 1 like I said this was a continuation of?

[@Donisgr]

Very nice tutorial, when the spot welder tutorial will be uploaded?

[@harukoyama9515]

I was wondering what is the different between your microwave mod and a electric stove ? Can I just take an old electric stove, connect the 2 end to burn some red hot wire? Is there any difference?

[@MattsAwesomeStuff]

An electric stove is just your raw, line voltage going into a socket. That'll be 220volts almost everywhere in the world. In a stove, you do not see the wire that connects to the main voltage. It is a smaller wire that is surrounded by chalky-white insulator that is then surrounded by iron. The iron on your stove elements is not electrically connected to your house, it's only thermally connected to the wire that runs inside it (inside wire gets hot, outside wire gets hot). Else, when you put a metal pot on the stove it would short out, or, when you touched a burner you wouldn't just get burned, you'd be electrocuted. What I've done with the microwave oven transformer is lower the voltage from 120v to about 24v. That's the point of a transformer, to transform the voltage. If you were to stick a wire into your stove element plug, you would instantly die. Don't do that.

[@JoshBrownPhotography]

haha the sense of humor is very good

[@MattsAwesomeStuff]

Script's done, I have extra microwaves. Takes about 100 hours of work for audio/video/graphics/edit. Could be a month. You're subscribed so, you'll see it when it arrives. If you're impatient: A spot welder is a 1-turn secondary. Use scrap copper. You can do it for free using your old secondary but it's laborious to explain in text. I see you like chainmaille, is it for that or for sheet metal?

[@harukoyama9515]

For a 18Vdc Bosch circular saw to cut 2x4 wood stud or 3/4 in ply wood with 7 inch diameter saw blade. How many peak amp do you think will take? I will need to find a full wave Bridge Rectifier "double" that amount of amp, otherwise FWB will overheat. Current is only draw when it needed. So basically I could watch current meter carefully not to exceed FWB to stay safe. Or I can install a current limiter or resister such as light bulb or ceramic resister. So light bulb will break the circuit before my expensive Bosch tool over heat. Is above the right practice and correct thinking? I also found 3 phase rectifier. It has 5 connector. Is it safer to have 5th prong connect to house ground wire. So it can have ability to trigger the house breaker if it need to? Below are the 3 phase FWB (full wave bridge or block?) 1x MDS150A 3-Phase Diode Bridge Rectifier 150A Amp 1600V Bridge Rectifier 3ph 300A 1600V MDS300A diode 3 phase 300 amp 1600 volt 1pc ------- I am also looking to install a capacitor as you recommended. What size of capacitor will I need for this build? How do you decide what size it need be? By peak amp draw or by volt it provided. As I understand. Capacitors job Is to discharge all the DC voltage at instant. Will capacitor over Volt my Bosch tool? What will over Voltage due to tool? I have many old lab top charger. They all have larger size capacitor inside. Thinking to just parallel them on a rail with their short leg. Just add up the number in parallel as I remember from my physic class.

[@MattsAwesomeStuff]

1 - Peak amps? I don't know. Does it say how powerful the motor is? Watts / Volts = Amps. 2 - No, you probably don't need double. The correct amount should be okay. It doesn't sit at max long enough to overheat. 3 - You could watch the current meter, but, I wouldn't worry. You can just as easily touch the FWB and see how hot it is. A heatsink and small fan will allow it to take 200% of its rating for a short periods of time. 4 - That is not how current limiting works. Light bulb would never break. If you add resistance in series, it makes it so that is the maximum current that could flow. I would not limit current with a resistor. It will be fine if you are using an MOT. 5 - I would not connect the 5th prong. You do not need to use a 3 phase rectifier. Single phase is fine. The other phases are not in use. I only mentioned 3 phase because that is what you find inside an alternator. 6 - I already answered your capacitor questions. About 1000uF per amp, but you can use much less, the effect will just be less good. Use some. Voltage should be at last as high as peak voltage, if not 2x for safety. Capcitors only come in a few voltage ratings, so, 35v or 50v would be fine. Not too high or it's wasteful and expensive. 7 - The capacitor in this way is used to smooth out or average the voltage. Instead of being bumpy, it will be smooth like a battery. It charges up when voltage is high and discharges when voltage is low. It does not add to the voltage, it just acts like a little battery to help with interruptions. 8 - Yes just add up capacitors in parallel, if they are all at least the max voltage. I already explained this in an earlier comment.

[@harukoyama9515]

High current is what melting metal to red hot while high volts just make metal splitter in the welding process. I see. Thank you. Is there a different between AC and DC Compacitor? Is it all just bunch coil wrap inside the cylinder. Can Microwave Compacitor 200u uf used to store 36Vdc current for example???

[@MattsAwesomeStuff]

Capacitors are not coils, very different. Capacitors are not wire, they are two materials with chemical between them. Some capacitors are for AC or DC, some only for DC. Capacitors store energy. They have max voltage. How much charge they store is "uF". You want a capacitor that is higher than the max voltage they will ever see, but not too much more or you are wasting money. 2x voltage is a good ballpark. If 36v, then get at least 50v max rated capacitors. Or 75v. But not 100v, no reason. Same volume of capacitor at lower voltage will have higher "uF" number, which is more energy stored. Microwave capacitor is 2000-4000v AC but only 1uF. Useless, no energy. Same size, a 50v capacitor would be 20,000 uF. Microwave capacitor is only useful for microwaves, no other device needs voltage so high. Check computer, stereo, and TV power supplies for good large Capacitors.

[@arthursmith3154]

Thanks for the video you answered a of questions that I had. keep the video comming

[@phanzor9032]

Why did you stop making videos? You great videos with the most detail I have found on actual scientific explanation. I urge you to continue making them.

[@MattsAwesomeStuff]

+Nathan Anton I didn't stop. I have many scripted and half filmed, just not much to show. I moved, didn't have much room for a studio. I didn't want to film anymore with such a crappy camera (480p) and didn't want to spend money on a good camera (1080p). I gave lots of project advice to some other KZbinrs who now have hundreds or thousands of times more subscribers than I do now, and frankly, their production values were better than mine. HOWEVER. I have a new camera. I have recording space. And I really want to make more videos, so, hopefully I find the time.

[@phanzor9032]

+MattsAwesomeStuff Cool! I look forward to seeing them in the future.

[@andrewsmith8805]

i would just like to be able to rig with out spend money on a new one. i got this wall mount light kit from work a freebie the boss since i was always complaining about the neighbors kids sneaking in to my pool at night. He said with this they wouldn't dare i would see them a mile away. but gettin home and realizing its not a multi tap and only runs on 277v. some rigging is order. will the cap. and ignitor cause issues in reconfiguring?

[@AlphaTroniks]

Forgot to add I'm using 2.5 mm 6013 welding rod... Is that ok?

[@pauljordan3064]

Another great video with really clear and concise presentation, Thanks! (But I'd have to say that your skill in electronics and talent for teaching is equal in magnitude to your lack of carpentry skills lol)

[@99frofro]

Attempting a stick welder build with MOTs. Right now using two one I rewrapped the primary the other came stock, got about 35v open circ. voltage on the secondaries...using 120v wall socket primaries wired in parallel, although considering doing separate socket for each. Lays a decent bead down but so far can't get it to weld 1/8" steel together

[@MattsAwesomeStuff]

35v is a bit high, maybe, it's stealing all your amps. 1/8" may be impossible. Good job even getting a bead. Go devour some 1/16" or 3/32", see if those work better? Primaries in parallel are tricky, unless perfectly matched. But seems you've got it to work regardless. I cover this in some followup videos I haven't finished, because I treat my fans poorly and I'm lazy. You're doing well.

[@99frofro]

Update: Was able to attach some light mild steel together but very crappy weld "attachments". Wouldn't call them beads. Lots of slag getting in the way. 6013 too little penetration I need some 1/16 6011 which is extremely hard to find. Gonna try and get the 3/32 6011 I have working. Keeps sticking.

[@MattsAwesomeStuff]

Thank you for the kind words.

[@saviojsr]

hi sir could you pls explanethe science behind why some transformers hum while shorted and some don't.

[@stupid-handle]

By what you say on this last video, I guess it would be better to buy E and I plates to build a transformer to suit? Or are there some advantages in using an MOT core in terms of efficiency or power output (other than it's a block already made for us, in a smaller factor than a hand-made E/Icore could be for the same power, I guess)? Also, you showed in this series MOT's with their secondaries' wound around their primaries, but didn't gave them any specific mention? I guess these will perform much better at the cost of having to wind a brand new primary that covers the inner core?

[@MattsAwesomeStuff]

The only advantage of MOTs is that they're cheap. They suck otherwise. And yes, winding the other way just requires more wire and more work.

[@neonboy22]

I want to use an MOT to make a choke. to control the current going through a second MOT. HOw do I do that. DC wind and EIE format or ?

[@8990nathanm]

this was awsome man! I hbope you make lots more videos!

[@pietzeekoe]

So are you still ganna make a spot welder tutorial?

[@NWKEEN]

Approximately how many amps from mains to the mot am i to get to know the primary isn't shorted either from one mot or the two connected coz each on its own pull 5.1 amps at 237-240Volts and outputs 22 Volts.II'll try with the fan on coz of heat thanks.

[@harukoyama9515]

Your microwave mod transformer and electric stove both deliver watt. Micowave transformer high current low volt can be used for welding. So is electric stove socket where electricity is feed through the burner coil 220vac. It is just danger to deal with high voltage when welding. Is this correct? If yes. A robot can utilized 220VAC to weld without buck covert to lower voltage. Is this correct thinking?

[@MattsAwesomeStuff]

Close, but no. You cannot weld with 220vac directly. Voltage is too high. Not only dangerous (max legal welding voltage is 50v I think?)... but what happens in the weld. Too much voltage will turn metal into gas instead of liquid, and will take too much current. 10x too high of voltage = 10x too much current = 100x too much power (watts) and heat. You have to lower the voltage to 24-30v to weld, no matter what.

[@selador11]

Now I have a question. (or 2) You used a cordless drill in a couple of these vids. I want to start with a MOT, and end up with a power supply that will power a 14.4v cordless. Without burning up the drill. Amperage needed at 14.4 is about 40 to 45, under full load. So a 1000w transformer should provide plenty of amperage. I'll wind a secondary of roughly 15 turns. Testing to make sure I get within 13.5 to 15.5 volts in the end. (continued.)

[@PatrykDarasz]

thanks, bro, its a very good tutorial.

[@jimthvac100]

At the end you put power to your new rewound transformer, Is it really that loud? or did you add the loud noise for effect?.

[@MattsAwesomeStuff]

The hum at the end is not a sound effect, that's the actual noise. It might be a big magnified by sitting naked on a wooden table. Most of the noise is the E and I rattling against each other. The rest is the coils rattling against the core. Also, I did not do any of the things to quiet it. Even one strip of duct tape around the outside, more paper on the coils, a quick flash of a weld on the corners would reduce it to a whisper. Ideally silicone it or varnish.

[@jimthvac100]

I was thinking same thing if it was welded together the two halves would not of rattled against each other.

[@petergdk]

This series was really well made, and very informative. I'm in the process of making something as simple as a hot wire foam cutter, and i need a 2x12v/24v transformer, so i am able to swich between those voltages. You video made it very clear that i can just make 2 secondary windings, and connect them in parallel or series via an on-0-on switch, depending on what current i need. I see a lot of people using hot wire foam cutters, just putting a cheap single pole incandecent leading edge dimmer in front of the primary, to limit the current, and thereby regululating the temperature of the hot wire. Won't that cause problems with saturation? (I'm not even sure i completely understand transformer saturation, even though i've tried to read up on it - so i might be wrong). Anyway - your videos are great, and i really hope we will see more videos from you in the future, since your kind of videos, with both humor and educational value, that can be used practically, are few and far between. I can tell that you take pride in producing high production value videos, by the quality of your work, but i would be happy to see you sacrifice a little production value, if i could just get to enjoy some more content from you :). Good luck

[@MattsAwesomeStuff]

Glad I could help. I have built a hot wire foam cutter before using a car battery charger (old style, just a transformer and diode). I threw a dimmer on it (primary side, as you correctly figured) and it worked fine. No saturation issues for me.

[@harukoyama9515]

I have many 24vdc and 18vdc hand tools, 36V bike . Battery cost more then the tool, bike itself. I don't know why tool maker dont commercial make power supply for 24vdc and 18vdc tool. Did lots research on how to build a power supply as many people did on u tube... Found your with most important detail. Is it true buck and boost converter can only convert DCV back to ACV then back to dcv? Conversion can only take place in AC environment?

[@MattsAwesomeStuff]

A transformer only works on AC, it will melt with DC. But a transformer is not the only way to change voltage. "Buck" and "Boost" converters are special types of DC-DC converters that use electronic circuits instead of transformers to change voltage. Generally yes, what they do is "chop" the DC into something that looks like an AC wave, and then put that through a transformer (a very small one, because they will switch very fast which means you can use a smaller transformer for the same power), then convert that result back to DC. If you are building a power supply, note that you want to only reach 70% of your DC voltage target, plus 0.7V total, because your capacitors will charge to peak voltage. So, to convert from 120vac to 24vdc, your transformer should actually convert 120AC to 18vdc (70% of 24 = 17, plus 0.7v). However, you can buy very cheap DC-DC converters online that are very good at changing a range of voltages very precisely. They just usually can't take 120VAC. So, use a transformer to step down to something closer to their max voltage, use a FWB Rectifier to make it DC, add in a capacitor, and then use that as the input into the DC-DC buck converter to be very precise and finish it off.

[@harukoyama9515]

Question 1: I have identical multimeter rated for 10amp. I was wondering if I can parallel them like battery to read 20amp? Or somewhere between 0 to 20amp. By adding the 2 multi meter reading together? Question 2: I found many 100amp, 50amp, 10amp meter with special shunk to reduce current. So it does not burn out the meter. I was wonder why people wouldn't just buy a 100amp for all purpose. Is 10amp reader read more acute for anything below 10amp in compare 100amp meter trying to read amp below 10amp? I just don't know.

[@MattsAwesomeStuff]

A1 - Yes and no. If you use two meters, you can add the amp ratings of each to get the total amps. But, the meters not guaranteed to share equally. One might take 18 amps and blow up, the other might only take 2 (until the first blows up, then it will take all 20 amps). It will depend on how identical the two meters are. Difficult to guess. A2 - "shunt", not "shunk". The shunt is not to reduce current to not burn out the meter. The shunt is so that you know exactly the measurement because of a very small voltage drop across the known resistance of the shunt (it's how an ammeter knows how many amps are flowing, it measures voltage across known, very-very-very-low resistance, Amps = Volts / Resistance ). However, a couple reasons why there are different sizes of shunts. One is that bigger ones have more material and cost more to make. Another reason is that measurement devices are most accurate in a specific range. If you want to measure 1-10 amps, you should use 10. If you want to measure 10-100 amps, you should use the 100. If you use the 100 to measure 1-10, the meter is observing a 1-10% change rather than a 10-100% change.

[@jaimevaldez9597]

Can you post a how to make low voltage landscape transformer (1200watts) with a microwave transformer. I want to put alot of lights outside, plus a water fountain

[@Anurag2701]

Hey man.... I have a mot and I made a secondary for 25v. But when I plugged it in for the first time (without load) my MCB tripped! Is that normal or I'm doing something wrong... I didn't touch the primary winding, it is as it was. Should I put a load resistor on the secondary in parallel to make it work??

[@MattsAwesomeStuff]

+Anurag Trivedi - Hard to diagnose via description. There's a few options: 1 - The primary is shorted to the iron core, either by scraping it when you took it off or from vibration or weak insulation or something else. 2 - You may have one winding shorted to another winding in the primary, reducing the effective turns count and causing too much current to flow. 3 - Your breaker is just sensitive. 4 - The inrush current from the MOT creating the magnetic field is too high. 5 - There is something else plugged into the circuit and the waste heat of the transformer (several hundred watts perhaps) is pushing it over its limit. 6 - If the secondary is shorted internally or to the core, causing a huge load, it might be too much for the breaker to handle. A load resistor on the secondary isn't going to help, the "resistor" of air between the contacts is already tens of thousands of ohms. Give it an inspection and check for faults. Or move it to a breaker that for sure has nothing else on that circuit (not just an empty plug).

[@dav3fk]

Hey matt - I'm looking to make a 110v stick welder for low amperage stuff - there seem to be a lot of people who have a lot of tutorials on this sort of thing, but all of them either have glaring (even to me, an electrical idiot) safety/functionality issues, or they build something a lot bigger than what I want, or complicated in all the wrong ways, with no particular gain. I was thinking of a dimmer switch to control the output from the primary side, and hoping that I could simply have one transformer, (maybe, hopefully)with the welding cable wound directly as the secondary, such that I could have a welder in a box the size of a large MOT, with just a power cord, two leads, a knob, and a switch, capable of running 3/32ths electrodes. With the videos out there, I could absolutely figure out how to build a bog standard buzzbox, but I have one of those, I want something the size of a lunchbox that you can plug into a normal outlet and start welding with. I could live with multiple transformers, but would much rather have one - at this time I have the transformer (and capacitor - which I thought might be useful in helping to get an arc started, I could be misunderstanding things though) from a 1000w microwave, but could probably get one from a pretty big (industrial, or nearly so) one if needbe. The popular videos on microwave welders are exactly what I do NOT want: different 110v sockets powering a sprawling monstrosity of a fire/electrocution hazard - making a few passes is totally acceptable to me, having a shameful disaster of a welding "machine" is not. I know that this is intellectually lazy of me, and that I should be able to study up and answer my own question, but it seems like something you should be able to answer off the top of your head, with your handle on this stuff, and I'd rather not delve deeply into it, just to learn that I'm wasting my time and it's impossible.

[@MattsAwesomeStuff]

4 diodes or a rectifier you need, any can handle the voltage, but they must be sized for proper max amps. Fairly big, Ratshack probably doesn't have any. The control board in the microwave might have small ones you could try and fry. Rectifiers are black with 4 leads and usually a corner cut. Also, you need capacitors to smooth voltage bumps. At least 20V (much extra won't help and will add cost), and hundreds/low thousands of uF. Hard on motor otherwise.

[@luigibraga6955]

ciao mister MATTS AWESOME vorrei chiederti una informazione che tipo di colla devo usare per unire bene le due parti del trasformatore dopo aver inserito il primario ed il secondario modificato ?. CIAO E GRAZIE ANTICIPATAMENTE il tuo video è OK

[@capitanespacio2844]

hi! I’m making an electromagnet as a small part of my engineering thesis. The thing is, I’m a chemmy, not an electro guy. My project involves the highest (constant not alternating) magnetic field possible within an air gap of 1 cm. I already have the E and I and the primary. Maybe I could ask for your advice on how to crank the max of the core/coil to make as much field as possible. If there is no problem, and you could share some ideas I'll lend you my e-mail.

[@mainelyelectric]

SO you say they use more power when I remove the shunts? why would that be? I don't understand. i have made a few modified mots into spot welder power sources and removed the shunts should I have not? Thanks Ben

[@MattsAwesomeStuff]

The shunts are there to limit the max current. If you remove them it allows you to drive the transformer into really abusive amounts of saturation and low efficiency... but terrible efficiency or not it does grant access to a bit more power on the output. For a spot welder, I would remove the shunts, yeah. Spot welders are so brief (less than a second usually) but need every drop of current you can squeeze out of them that this is a good tradeoff.

[@mainelyelectric]

Ok thanks great video and info btw.

[@careful34]

Great videos! Thanks for making them! It seems your newest is about 2 years old at this point. Have you moved on to other things, or do you have another channel somewhere? Weird how sometimes a channel takes off, and sometimes it doesn't. Hope this one catches fire (in a good way)!

[@MattsAwesomeStuff]

+careful34 I'm still around, no other channel. I have so much content planned and half filmed, dozens of hours. I just suck at completing projects and my educational/volunteer efforts go elsewhere these days. I think my channel has caught fire, I mean, I've got like 4 videos and am coming up on a half million views. That's pretty nuts for a slacker :). I was very close to filming a new video yesterday, I have a new camera, so, hopefully soon. Thanks for the encouragement.

[@careful34]

They're very good vids! They deserve to take off! All about self promotion and all that. Hope to see more of them! Good Luck!

[@anayberwer4433]

what is the thickness of the wire in primery coil of wilding or in secondry of transformer

[@MattsAwesomeStuff]

+ANAY BERWER Primary is usually 16 gauge and secondary is somewhere around 26-30 gauge.