BEST Microwave Oven Transformer-MOT Rewinding Tutorial
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- เผยแพร่เมื่อ 26 ก.ย. 2024
- This video shows you how to rewind a microwave oven transformer (MOT) for use in my 12V Lead Acid Battery Charger Circuit, or my 52VDC Stick Welder. This highly detailed, and excellent tutorial will allow you to rewind the secondary(2KV) winding with ease. This procedure can also be used for other circuits, and applications.
52 VDC Stick Welding Unit Here:
• Microwave Oven Arc Wel...
12V Lead Acid Battery Charger Here:
• DIY Lead Acid Battery ...
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Thanks for making a video with clear instructions and voice without loud distracting stupid music !
You're welcome Ed! Be sure to check out the very wide range of videos on my channel, and most importantly share my YT channel with others. Thanks
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I noticed that you were using a carpenters chisel ; I used a mechanics chisel and things didn't go as smooth. I had a time getting the winding out ! I ended up putting the transformer in a vise and just hammering away at the coils with a punch. After about two hours, I finally got it cleaned out. So, thats why I came back to watch your video ! Nice Job ! Like all of your videos ! Thanks !
Very good information given in the video. Many thanks!!!
U r Excellent Teacher. I will rebuilt following your instructions. Thank you so much.
Thanks for the nice comment Joe! Good luck with your transformer. Be sure to rate thumbs up, subscribe, and share my YT channel with others.
best transformer instructions. thankyou
Despite what others have said about the video I give a thumb up. You made everything very simple and to the point. For me it doesn't matter where and what material you're working with. What matters is what knowledge I get from it. Thank you for keeping everything down to earth!
Glad you enjoyed the video!
After watching this, I am impressed with your speedy system of MOT modification without separating the core. This made for a relatively quiet filament power source for my VTTC. Thanks for posting.
Glad you enjoyed the video!
Well that's a bit harsh. I worked hard on mine. I guess I'll just go remove them then....
clagwell: Thank you for the kind remarks.
MattsAwesomeStuff: I see you also put together a few videos, which I could see you put a lot of time into. Good Job.
My latest video showing a step up/step down MOT conversion:
DIY Custom Power Transformers
MattsAwesomeStuff Both tutorials are great for their individual respective purposes. My remark was harsh and unduly all-encompassing and I have amended it. My apologies Matt.
For reference, my original remark read as follows:
"After watching this, its clear that all other MOT rewinding tutorials should be deleted. Excellent tutorial! Thanks for posting."
clagwell
Obviously your statements were made with humorous hyperbole. Mine were made with mock seriousness. Carry on :p
you can get more turns with magnet wire as the insulation is thinner.
I used a hacksaw to cut mine off then drilled both sides out with a drill press. Easy as pie if you have a drill press!
Brilliant tutorial. Thanks so much.
Glad you enjoyed it Bob! Be sure to rate thumbs up, subscribe, and look over my video playlists below for many other videos of interest to you. Taking one minute to share a link to my channel with others on social networking sites would be greatly appreciated. Happy holidays!
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It is CRITICAL that the two transformers are wound the same way to be connected in series. If one is wound "In Phase" (Same Direction as Primary)and the other is wound "Out of Phase". then the two in series will not work. If you wind one "Out of Phase, NOT in the same direction, 180 Deg off, Then you MUST wind the other transformer also "Out of Phase" to be able to connect them in series.If You have 1 MOT Primary wound opposite from the other, you can correct this by winding 1 MOT Out of Phase
Other info. I researched is that these mot have shunts; I didn't find any as I noticed you didn't either after watching your video. Thanks !
Went out and bought a copper grounding rod for 10$ at the home store. Is 8' of solid copper thats 1/2" around.. i sanded it down to just enough to completely fill the space in the transformer then dipped it in floor varnish 3 times along with the rest of the transformer. Cut off the bottom of the transformer though and sanded the varnish on the mating surfaces and a corner on each side. With the winding in its home i hooked one side to negative and othrr side to the positive electrode holder from my stick welder, rubbed a little tinning flux youd use for pipe brazing then with gloves and welding mask on and machine on 200a ac and just gotta make sure that you hit both sides at the same time so i used 2 pieces of wood to guide me and slapped together. No sparks came out and i switched off the machine as soon as i could get to it. Worked perfect.. two halves are together and wont come apart, the winding gives me 120v in and 2v out with enough current to blow my 1500a shunt so 2ka i guess.. dunno. But it makes a hell of a supply for an hho generator and can stay on with a fan indefinitely...
İ watched many videos but i didnt learn information as much as your video even i dont have a good english😁Thank u
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Probably the easiest way to remove the sec. In the past I've used an angle grinder, slotted drivers, and a rubber mallet to remove both the primary and secondary....reusing the primary, winding a low voltage sec.....like you've done here. Twice I've had to 'roll my own' primaries. Not very efficient but neither is the stock transformer. You can do a lot of fun (inefficient) things with these.
I've rewound a lot of MOT's. If you have access to a stick welder, I've found that its much easier to use a Dremel with a carbide cutting disc to cut along the weld that holds the laminations together. Usually, you can cut the weld on one side and wedge a flat screwdriver in the cut to pry apart the "top" of the transformer. After the "top" is off the windings will just slip out. When you're done rewinding, if you have a stick welder it's easy to put back together. Believe it or not, I've actually had success using a 150W soldering iron and solder it back together most won't have an iron that big though.
When I have kept the laminations intact, a tool that makes short work of cutting the secondary is a oscillating saw, sometimes called a Fein tool. it makes a very clean, mess free cut and usually you can just push the leftovers out with your finger.
+Chris Barth i'm in a college dorm, so welding will definitely be out of the question. Would it be possible to clamp the top back on and fill the groove with a good epoxy?
I wouldn't trust epoxy or JB weld to work well enough for a permanent hold, there is a lot of vibration and heat when running these that will probably cause the bond to fail. I've used clamps to hold the X fmr together while energized after rewinding. It worked well, it just a little unwieldy. I've used C-clamps and the quick squeeze/sliding bar type clamps to hold it together.
+Chris Barth One more thing, after removing the secondary coil and before rewinding, its a good idea to make sure that the iron laminations are insulated. You can use the existing wax type paper for insulation but it may not be enough. I use Kapton tape and wrap it around any exposed areas, Kapton tape can take a tremendous amount of heat, you wont find it in stores though, Amazon or Ebay has it cheap. Electrical tape is a poor choice because it will likely loosed/sag because of the heat build up if you're running it hard or for extended periods without a lot of active cooling.
It's easier to multiply the RMS AC voltage by 1.4142 to convert it to peak, which would be the DC voltage across the caps...but don't forget the voltage loss across the rectifier diodes, with a full bridge you are looking at around 1.4V
TLDR:
VDC=(1.4142 x VAC)-1.4
Assuming sufficiently large filter capacitors.
I want to tell you that if you apply mains to the high voltage winding you can then get 50v ac out of the old 250v winding without doing any taking to pieces. You should know that taking out the shunt core reduces the inductance and the mains winding then takes a lot of current and the transformer will get very hot even with no load.
Very good video you have a new subscriber!!
oke.. this is a really nice project!! went straight to the store and got me an old microwave which was returned for scrapping. they were happy to get rid of it and i was happy to have it :D
must say.. i live in europe so my transformer is a 240V version, which i feel shows by thinner wires on the primairy side (compared to 120V) and more windings ending up in a higher resistence (2.5 instead of 0.5). took out the secundairy side and the red wires.. I did just so gently touch the primairy side with the hammer, only some slight deformation there..) resistance is still the same so i believe it will still be fine. it's really just minor. I feel i'll find out when i'll try it out.
but i have a something else that bothers me more. At the end of the inner side of the wire there is something connected before it goes to the end pole (so between the beginning and it's pole). i don't know what it is. it WAS insulated (will do again but had to remove it before i could read it. it says ck01 and L145 and i have no idea what it could be. it is easily removed if i need to. fiddling withit i did notice some minor changes in resistence (max up to 9.0)
anyone have any idea?
would have loved to post pictures here but..
i'll try to add the links from dropbox below.
www.dropbox.com/sh/c4xroh6boexpe79/AABtShZB3U6xHPRQ2oBotwFka?dl=0
Excellent Video!
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If you just want a rough transformer that will get you a certain voltage without being very efficient or powerful then this method is ok, but if you would like peak performance and power like in a mot stick welder or high amperage battery charger you should cut the transformer to (CAREFULLY) pull the whole coils out of the core, knock out the magnetic shunts, add a few (about 10-20) more turns to the primary side, and make a simple winding spindle with blocks of wood slightly oversized to the transformer core to tightly (key word TIGHTLY) wind some SOLID core wire of preferably the enameled variety (I've made similar wire by wrapping teflon pipe tape around bare copper wire) and letting some thin enamel of some kind (clear fingernail varnish works great) soak in between the windings or brushed on between layers to keep the copper winding solid so it doesn't fall apart on you. A lot of people consider this overkill but there's very little extra work for a HUGE increase in performance. You're not just increasing the power handling with the extra copper, but the tighter windings, extra copper, greater fill efficiency, removing the magnetic shunts and more primary windings give a much higher performance to effort ratio and some MOT's can be ran continuously at a couple kilowatts or more with this arrangement. To be honest, if I just needed something lower powered like what this guy is doing I would just add one of those cheap buck boost modules to a laptop power brick, infinitely variable voltage within a certain range, automatically smoothed output, both voltage AND current control, higher efficiency on your power bill, and can fit in a smaller space, and the price is usually pretty similar to what you'd have to pay for all of the components to make the mot power supply work since you need extra diodes and wire and capacitors yet you lack several of the features of the buck-boost-brick setup. If you need higher voltage then you can put a couple buck-boost-brick setups together in series as long as they are otherwise isolated.
Outstanding video,
thanks
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Nice video, the best hand held meter in the world for electronic repair is the one in your hand. The Wavetek 27XT, I've had mine for over 16 years and use it almost daily at my electronics job. Shame they don't make it anymore. Anyways nice video.
+Keith Noneya
Thanks Keith. I bought mine in the late 90's for around $120. Check out my recent reflow video. I swapped out an IC in my Wavetek.
+electronicsNmore Cool send me a link or the title i'll check it out. Keith
Keith Noneya
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Each lamination is insulated from the other, to prevennt Eddy currents, so when you test with Ohms to see if there is a short, you are only testing the laminations that you scratched, another way to test, would get the Ohms resistance rating for the wire on the primary, test that, if it is within range then it is not "grounded", if the Ohms is Higher, then it is shorting.
The weld across the laminations keeps them all together, so they can't be insulated.
Excellent tutorial! Thank you a bunch!
Glad you liked it. I have many interesting videos, and more microwave oven transformer videos as well.
Be sure to rate Thumbs Up and share. Thanks.
I would have used vaseline or mineral oil to lube wire it is a better lube and nonconductive soap is usually conductive. this is a great video.
+Charles Barnett
Silicone grease and wax based lubricants are the best. The soap works great, and there is no concern about the conductivity of the soap, unless you cut into the thick insulation of the wire.
Thanks for watching!
Insert a short piece of 1/16" piano wire (about 4" each) being at the top and at each end on one side of the primary (tap in lightly with hammer). Cut close to the iron core with a fine tooth hacksaw. The piano wire is too hard for the hacksaw blade to cut so it stops the blade preventing the primary from damaged. I just cut the secondaries off two transformers. Ten minutes each and no damage to primaries.
Thank you
Try taking a car battery ground strap for a single turn secondary. That makes a DIY SPOT WELDER. (You will need a Variac on the primary side to adjust the power.)
th-cam.com/video/BQikyXMeC7w/w-d-xo.html
If you test the open circuit amps in the primary ( 120 volt input with no secondary connection ) , you will find it draws nearly 1 amp idle current and that means you waste about 100 watt power. The microwave transformer is not designed to be powered constant with the primary winding it has, and needs nearly double the amount of winding for the idle current to be low in the primary. To properly use these cores requires a rewind of the primary coil as well as the secondary. Just a little info for you. Test yours under no load, power on and see what primary current you have. Then feel how hot the cores gets after just a few minutes. Do your calculation (120 volt times the measured current) = roughly the power consumed under no load, that power is making the core heat up.
Yes, if you want an efficient transformer, you'd rewind both.
Nice video.. One question though...if you used the grinder to sharpen the chisel, why not just use it to cut through the windings? or better yet, make a small incision at the weld on the side of the transformer, and separate the "E" portion from the bottom... So you to can slide the windings out whole, and easily rewrap the new wire. Then you can just re attach the bottom of the transformer to the "E" portion, and weld it back together, no problem....assuming you now have a welder.
I used a Hack Saw to remove the winding . Just cut one side and punch the rest out with a long bolt. Like 5 minutes tops and a pile safer on those winding's. If I had a welder I would just cut the welds and take it apart.
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Enjoy your shows though thanks
I like the improvisation, also called "jugad" in India.
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very good video congratulations.i have one question, what if i use 220 volts on primary?
Hi bro nice informative vedio , can i use the primary as the secondary for 220v and recoil the top winding for the primary and supply 110v through it.
I tried and a spark jumped a gap and put me into cardiac arrest. But I wasn’t far from ER so I’m fine now. Some of the damage was to my muscles. Every muscle in my body contracted causing tiny tears Called micro tears. Causing my sport career to delay. Until now
How rare tables and/or work benches are in these vids. Everybody is working on the floor!
I was living on an Island in the Bahamas...My work area was in a dark location, so the garage floor was best.
It is very informative, thanks a lot. I congratulate you and thanks alot
You are welcome!
Even if you scuff up the primaries, not all hope is lost. You could probably just run nail polish on the bare spots and they would be fine.
+Fire In The Sky
True. I used clear acrylic nail polish many times in the past.
When I was knocking my secondary out the bolt put a pretty big scratch on 2 wires so I pulled them away from each other an then put silicon in between them and it hasn't blown up XD
thanks you saved me
Great job with patience
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Sorry... I seem to have missed your implied use of multiple transformers (my bad) :( --- Many thanks for the reply!!!
22:30 Multiply by 1.414 ... That is the correct factor to use in order to obtain the voltage after rectification and smoothing
You don't think I know that?
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Health and safety !!! Should be wearing steel toe cap sandals
Nah, I've been walking around in flip-flops my entire life....even climb with them. :-)
You should get a proper insulation tester to test the insulation of the windings at higher voltage (500V/1kV).
I have one, as well as a video on my channel. :-) This video was made for the AVERAGE person, not people with Meggers.
its a good idea , very nice
Shay Shen Thank you!
Best video thanks bro
excellent
Hi. Please let me know what thiknes could I on secondary for DIY power supply at 30v DC max 3 A. Thank you.
In contrast you don't need that large of current for a spot welder. Drop the 10 gauge in half and you should be able to use it for 45V spot welder because you'll get more turns in, albeit at less current. 10 gauge will melt some wires without regulation so a smaller gauge should work just fine and last you a bit longer. I would use it for spot welding battery tabs and use a mosfet with a pwm signal so it doesn't burn up wire or heat up batteries too much. 10 gauge is way too hot for this application as it will put too much current into the battery for welding and it could explode the batteries... Just a thought. Pick an application and design it for that. I think this is a good general purpose application for spot welding thick steel. Kind of overkill for much smaller applications. Because the mosfet is pulsed it can peak higher currents. Therefore you don't need that thick of a winding. It will only deliver max current for a very short period of time...
Great vid, thanks.
robviolin1 You're welcome Rob! Please be sure to check out my other videos, rate Thumbs Up, and share.
Thanks
dear sir when i was removing secondary winding of mot i damaged the primary could you please tell me how many turns and layers requred on primary winding,?
I just plugged mine in an it hummed really loud.. there's no nicks or scratches in the old primary.. Gonna watch some of your other videos to try an see what I am doing wrong. I'm shooting for 7volts for perchlorate electrolysis.
Some humming is normal, but not really loud. Maybe your new windings are not tightly wound. Did you check the output to make sure it is 5VAC? Once rectified with a smoothing cap, you will have around 7VDC. Make sure the primary and secondary windings are isolated from the metal core. Place your DMM on a very high ohm range(10-20M) and check from each wire to the iron core. If you get any reading, there is a problem. DO NOT torch the probes with your hands/fingers during the test.
No mention about the shunts in the transformer core.........should they be removed or left inside......after you removed the HT coil and the Red wire..???
Edit...... noticed that this was answered in the comments 2 years ago.....
Es mas sencillo si cortas la soldadura del nucleo en la parte de las I con una sierra y luego separas la bobinas sin dañarlas para su reutilización, saludos.
Pablo Rivero English
New subscriber here.
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Hi, I need some help. I have very little electronics knowledge. However, I'm trying to build a power supply for my cordless power mitre saw. I've been told the best way forward is to use/adapt a microwave oven transformer. That's why I'm contacting you because your an expert and if you can help me, I will be grateful. My cordless mitre saw runs off 24v batteries ring from 2.4ah to 3.0ah. The motor requires 630w of power.
It's been suggested that I use a 700w use MOT and adapt it, rewire the secondary and so. Ok, that is were my knowledge ends. Can you please advise me the following;
1. What size MOT to use 700w or other
2. What size wire should I use on the secondary 4mm, 6mm and so on
3. How many turns does the secondary need
4. Do I need to use a bridge capacitor
5. Do I need any other electrical wiring
Please help as I really want to get this project off the ground.
Kind regards
Frame Please refer to my other video below. There is a link to a program which you can use to figure out what your need.
Thanks. Be sure to rate Thumbs Up and Share.
th-cam.com/video/3uCuA032lYw/w-d-xo.html
Why worry about the winding direction? Unless you are intending to interconnect primary and secondary the winding direction are immaterial.
Exactly. That's why I suggested putting things back the way you found them. I use (2) of these in series for my DC welder. Phase matters.
electronicsNmore - thanks for clarifying that :-))
What's the no load core losses of this thing?
I have been trying to remove it all day
+jarek da boss !!
Never had one I could not quickly remove the winding from, and I have removed MANY. :-) Use the correct tools, and some strength, and you will get it.
my drill didn't work and I tryed to hammer it but it removed some wire the rest bends and I don't have any thing that will work
I live in flip-flops. I do everything while wearing them, from climbing mountains in Arizona, 20 mile bike trips, to construction work. I am very proficient with them, rarely get injured because of them, and because I never wear shoes, I have no toenail fungus! Well ventilated feet.
When I lived out in the Mojave Desert in California, that's all you wear most of the time.
@@ronniepirtlejr2606 I wear them 95% of the time for the past 25 years.
Good for you.. except wearing open toe shoes doing any kind of construction work.. theres a reason osha has that little rule for construction sites.. you can be careful all you want but shit happens, ie hard hats, safety glasses.. wearing open toe shoes when grinding or anything is like not wearing eye protection, your ok until your not..
What are thoseee!! 👍👍 Good video
Glad you enjoyed the video! Be sure to rate thumbs up, share, and subscribe. Thanks
I have subscribed 😁
Somewhere around 15 or 16 turns mine got all mixed up and not very uniform ... The last 2 or 3 were pretty tough getting them through ... I also used 10awg solid so it was extra tricky haha what a finger work out 😆.... I just now got finished rewinding it and have not tried it yet but I was wondering if you have any idea if it will work at all using a solid/single strand ..also I now dont have a working dmm ... 😣😞 haha ...
Hello, why must respect the meaning of the secondary winding in the direction of primary winding, thanks !
+costache George vama vede hotel cismigiu
If you only intend on using (1) transformer, then not an issue, if you're going to use 2 wired in series, then the direction matters for phase.
I would like to do this for a spot welder. Remove the shunts or not? Do I require thicker gauge wire? 4 gauge or larger? Will the 10 gauge not melt from the current?
Hi there,
The shunts do limit current, but from my tests, not by that much. MOT's tend to run hot anyway, so I would leave them in. You can always remove them later to see if there is any difference in output. My DC welder works just fine using 10ga wire and 1/16" rods. There is no wire heating problems. If you are looking to make a low voltage very high current spot welder, then use 4ga or larger copper wire(larger is better!). You only need a couple turns on the core using heavy wire.
Thanks For watching! Be sure to share and rate Thumbs Up.
You just gotta cut it off to separate MOT' core into 2 letters. You just have to before you get lazy and follow this procedure. This is actually a whole week of very tiring effort and nicely edited to 10 convincing minutes. I have rewound countless MOTs and the best quality winding to replace your secondary is solid bare copper wire slid into 20 feet of shrink tubing and bended the windings into wood bobbins then transfer it to the core. Doing it this way you will get frustrated and most likely to hurt someone if not yourself . Yes its true. 👉🏽
I've done many this way, no problems at all.
electronicsNmore That comment was totally unintentional. There was an idiot who happens to be sitting here and he did the comment without my consent and so please disregard that. You are doing an awesome job and I just completed my connection based on your post. 😎
What a great video. How long of a piece of secondary wire did you use before you started to wind the secondary. I don't want to cut 10 feet and then find out that I am 5 feet short of finishing the secondary wind.
20 feet should do it.
Be sure to watch my other videos as well.
Thanks!
When calculating AC voltage to DC voltage what does the 0.4 number come from? is that the resistance of the secondary winding?
When you convert from AC to DC and add a capacitor to smooth out the ripples, the resulting DC voltage is 1.41x the AC input voltage. The reason why this occurs is simple. When you measure AC voltage, you are getting a voltage reading which is an AVERAGE. If you look at 120VAC on an O-scope, you will see the waveform swings from high to low. If you measure from the middle(zero line) of the sine wave to the very top, that voltage is 170VAC, then it swings down to -170VAC. When you convert to DC, the resulting voltage will be the "peak voltage" of 170V. By adding the capacitor to the dc output, all those ripples from the upper part of the sine wave are flattened out to give you 170VDC.
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** knows there has to be a pun about a bistable flip-flop latch switch circuit in here somewhere **
It was so easy to cut with small electric cutter
Just grind bottom weld out, knock it once and slide the entire coil out,, do your thing and weld or epoxy back together
Hi Bruce, I have another video showing that. :-)
Just got 25 wraps of #4 solid copper wrapped inside the same size tranny. Choke for huge DC Supply.
how much current would 4mm squared wire give out if i rewound a mot with it its household wire with 7 thick strands of single wire that make up the wire itself
the mot has 6170w marked on it i believe its the rating of the transformer
hansley maharaj I have no idea. That number does not sound like the rating. You need to do a Google search for that part#, and use the software shown in the video description area of my DIY power transformer video.
Thanks!
Maybe easier to use a dremel with small cutting disc?
Fritz Mulder Absolutely not. It only takes a few minutes to chop out the HV secondary. Seems longer because I made the video. If I was not making the video, I would have it chopped and removed in 3-6 minutes.
Thanks. Nice video. What is the rating of this transformer? I need to get one to build myself an inverter. Currently, South Africa can't deliver its power demand to the people and we have load shedding almost every day.
1000W, but they are really designed for around 600W. They push the limit because there is a cooling fan in very close proximity to the transformer.
Thanks For Watching!
600watts is perfect. I just need something to run a couple of lights and my 42inch Led tv for 3hours max.
It depends. Most microwaves are on the order of 1000-1200 watts but some of the bigger ones are up to 1500. In the US, plug in devices are limited by Underwriters Regulations to 1500 watts on a normal 3 prong, 120V outlet. If you are going to use two transformers to get twice the current, wire the primaries in series and use a 220 volt dryer plug.
I've been harvesting various parts of microwaves and I noticed that some of them don't have standalone transformers but have integrated components on a power converter. The converter feeds directly into the magnetron. Any recommended use for these other than desoldering the components for other uses? Also, is this typical of more modern microwaves?
what if I wanted to get 3 wires from the primary (center tap) how would I wrap that?
Very easy. Wind 1/2 the turns onto the core, then add a center tap, then continue winding the other 1/2 of the turns.
Check out this video as well:
DIY Custom Power Transformers
Thanks For Watching!
Hi, i think this is easyer way to calc ac to dc. Vac*1.40=Vdc or to be precise Vac*1.41=Vdc :D
+N!cky
:-)
th-cam.com/video/9GvlGUbiPRo/w-d-xo.html
Thanks For Watching
+N!cky
:-)
th-cam.com/video/9GvlGUbiPRo/w-d-xo.html
Thanks For Watching
+N!cky Not really precise, you have to count diodes drop voltage in...
CORECT !! BUT MABY HE IS USING LOW DROP ONES BUT STILL THEY HAVE A DROP
+PanJa yeh sometime (depending on what type your using) they can drop from 0.3 to 0.6 volts
Why do you insist upon maintenance of primary to secondary phase relationship (i.e. winding direction)??
Great vid BTW :-)
Why does it matter which way the coils go? I mean it's AC, so the current will shift polarity 100 times each second..50Hz.
If you're going to use (2) transformers in series or parallel, then you need to make sure the phase is correct. If you're only using one, then no big deal. I do it out of habit because it makes things easier.
electronicsNmore Ahhh...now I understand why. If you use two transformers in series and the phase ain't correct, they would cancel each other out. Thank's for explaining that. I'm not a pro on electric things, as my profession is blacksmithing and machining. I want to make a compact spot welder for my workshop, hence the interest for such transformers.
Kalle Klæp
If you only wind one transformer, it won't make any difference which direction you wind the transformer, especially if the output is converted to DC. :-)
electronicsNmore Thanks a lot for your help, I appriciate it..
from the secondary that i rewound, I got a reading of 24.5volts ac
The voltage depends on the number of wounds. More winds means more voltage and lower amperage. It depends on what you want to accomplish, each wind is about 1.2 volts the more winds the higher the voltage the lower the amperage. If you'd like to spot weld use extremely thick wire and wind it twice, you'll get about 2.1 or 2.5 that will suffice. For welding with welding rods use 10 or 8 AWG add more winds, 15? 17? and for lead battery charger do the math and measure the voltage. A 12Vdc could charged at 14 to 15vdc do not use too high voltage or else you'll fry the cells. Additionally, you'll need need rectifiers to convert AC to DC. Do messure your output and consider your input in the primary, 117vac or do you live in Europe??? 220vac. Greetings, my friend.
how many volts should the two secondary wires put out. not the one that goes to 12 volts. can you please help on the inverter..
+Andy The Truth
VAC output will vary. You can adjust the output by adding or removing turns from the low voltage side of the transformer.
+Andy The Truth
VAC output will vary. You can adjust the output by adding or removing turns from the low voltage side of the transformer.
thanx for this vid
Thanks for watching. Be sure to watch my other videos as well. I have a few more MOT rewinding videos in my playlists.
will do i have subscirbed it.s hard to find vids that show how to safely
hi, is there any different if i accidently swap in ""LIVE"" voltage into ""NEUTRAL"" for primary with this kind of project? will it cause explosion???
USE A HACKSAW TO CUT OFF TOP WINDING, THEN BANG THROUGH WITH PIECE OF WOOD......TOOK ME 10 MINUTES
I find a chisel to be quicker.
@@electronicsNmore I've used a grinder also but you're right, the chisel is quicker with less chance of damaging the other winding. It's also oddly satisfying with a very sharp chisel to cut a clean line across those wires.
Good video ,if I want to make a spot welder how long should be the secondary winding and how thick
I don't have thick copper wire so can I take several thin wire and put together to make thick enough
Hello, I never tried this myself but I think you can use several wires as long as you do not exced two winds. Do a voltage test first though, you should read a little over 2 volts, no more than 2.5. If it works the thicker the better, better inductance and less resistance = hotter.
Direction of winding is immaterial. This is AC. At 13:00 or so.
Jim Curtis If you are only using (1) transformer for a project, then you are correct, but when using 2 transformers in series(As in my homemade 52V DC welder), you need to make sure the phase is correct, so I like to wind them in the same direction. How the current enters the winding affects the phase.
OK so I got a micro hydro turbine puts out between 60 and 80 volts only problem is it puts out like 30 amps, how can I tie it to a mot or anything to get more amps?
You can't get more amps.
Is it really trash if the primary gets scratched? I saw a vid claiming to be able to fix the primary
It depends. If it's a minor scratch, you can apply some clear nail polish over the area. You need to make sure the windings aren't shorted out in the scratched area. Thanks for watching!
What has always confused me is the voltage is the number of turns but how do you know how much current you can draw? Say in the UK you have building site 110 volt output, how do they rate what you can draw in current? Thanks Ian
Larger diameter primary winding enamel wire, with fewer turns = more current input and output. Smaller diameter primary winding enamel wire with more turns will draw less current and you'll have a lower current output. Please refer to my DIY Custom Transformer video. In the video description area of that video you'll find a transformer calculator. :-)
informative...
You almost had me on the chisel method. Metal blade is quicker.
Use whatever you have on hand that works well. Thanks for watching!
bench vise is Ok but could invert it on two blocks of wood,
thanks for the well explained answer!! although does the voltage on the primary have an effect on the output? As I have an dual 24v toroidal transformer , once that has been rectified and filtered I get almost 40V DC!! My house has a mains voltage of 251 AC maybe thats why?
If you have a 120v to 12V step down transformer, and you supply 150V to the primary, then the 12V output will be higher. If the input voltage is lower, then the 12V will be lower. You have to connect the transformer to the AC power supply, then measure the output voltage under no load. Your 24V is likely putting out around 28VAC. That value rectified is 1.41x the AC voltage.
For winding the new wire, what length of 10 guage wire would be needed to make 16 - 17 turns for the welding circuit. ?
OR approximately how long should the 12 gauge wire be to create the battery charger to reach 13 - 14 volts ?
th-cam.com/video/deMmVK67HO4/w-d-xo.html
OK this has been bugging me, so I'll ask. How come you chop down in the direction of the primary winding? Why can't you put the transformer on its side then chop to the middle, where there is nothing that you need to worry about damaging? Basically 90 degrees to what I see going on here. I am really interested in the rationale for why that would not work. Because it is just not coming to me.
+Paul Frederick
Never been mentioned before, but you can do it that way also. You do it the way you feel most comfortable. You still have to be very careful because the primary winding is very close. The reason why I chose to do it the way I did, is because the steel plate on the bottom of the transformer makes the job much more stable because the plate extends beyond the cutting area. Remember, there is almost always a reason for everything I do. Thanks For Watching
electronicsNmore
Yeah right before you flashed up the message about holding the transformer in a vise I thought the same thing myself. You must be very flexible to work on the ground like you do. Those days are over for me here. I like to work like a gentleman today. I'd probably use this www.instructables.com/id/Make-a-Tripod-Vise-Stand/ because it is a perfect height for gaining an advantage over something for me. That is no accident either. I made it that way.
+electronicsNmore Some transformers are turned 90 deg already. I have 2 transformers that are setup the same except one has the plate on the side so it would be easier to cut it from the side like Paul said. I'll more likely be using a clamp and my porch hand rail to hold it anyway my self.
+Paul Frederick I just use a hack saw to cut, using a chisel sounds like a good way to screw up. I guess that is a bit quicker though.
Hello there. Using a sharp chisel is the easiest way. When you get close to the bottom of the winding, then you can use a 32tpi hacksaw blade to finish off if you do not trust yourself with the chisel.
How many feet of 12 or 10 gauge wire is needed if I wish to have exactly 12 volts DC later on after full wave rectification?
Not too much wire. Refer to my other video, "DIY Custom Power Transformers". I supply a link to download a free program. You enter the required information, and you'll get all info.
electronicsNmore hi I watch video in you your chanel I won't ask how can make transformer microwave 12 volt high amp for charging car battery thanx
How many turns and what gauge wire for the battery charger ? Also does the gauge of wire play a factor in the number of turns ? Thanks !
+robert freeman
Use 12ga wire. Refer to the video showing the lead acid battery charger I made. I forgot how many turns. I have too many videos. Thanks.
ok thanks i try
May be I missing something here, What's the important of winding direction ? and what happen if it made in the wrong one ?
It's habit for me to put everything back as I found it to avoid problems. If only making one, it makes no difference, but if you plan on using 2 in series, the direction of turns must be correct. Thanks for watching!
electronicsNmore THANKS
I will rewind a Mot next days.I want to make a lead acid battery charger .I have a couple of 100A batterys.I have just one question : does it get hot during function? I was wondering if it s necesary to attach a pc cooler .Thanks
+Silviu Cocolos
Use the microwave oven cooling fan positioned close to the transformer to keep it cool. :-)
+electronicsNmore Thank you ,i have a couple of capacitor 400uf and 80v each,cand i wire both in parallel ,i want to keep costs to minimum.
Excellent video... Thank you for the AC to DC calc.
While cleaning the transformer I took out all the paper and middle shunt.
I remember I saw one you tube video. It say that piece should be removed for more room to turn the primary copper wire. So I hammer it out already.
What does that piece of metal in the middle for? Used as spacer?
That piece of metal alters the magnetic flux which limits power output. I have many great videos on my channel that cover a wide range of subjects, so be sure to look over my extensive video playlists for other videos of interest to you and most importantly share my channel with many others. Thank you!
@@electronicsNmore What will limit flux do to the current?
Do I then received less current for my winding?
There must be a purpose of this shunt, otherwise manufacture will not have it in the first place. Is for safety? Current noise reduction?