Easiest MOT Salvage Tutorial Pt.3

Easiest MOT Salvage Tutorial Pt.3

Welcome to Part 3 of my tutorial series on
MOT salvaging, where I show you how to turn broken microwaves into cool projects. If you’ve
just come across this video, obviously it’s part 3 so go watch parts one and two first
or you’ll be lost. They explain how to tear down a microwave and its transformer the easy
way, and how to get the numbers you’ll need before you start making a new coil and putting
it back together. In this video, we cover some prep work, coil
winding, and the final reassembly. 1. Prep Work/Repairs Take out your core and the primary, and inspect
it. If you have a few laminations that splintered off, and the damage is mild, just glue it
and clamp it back together. Else, just rip them off. If you have leftover varnish on
the inside of the core walls, you can chisel or file or sand it smooth. It’s not necessary,
but it’ll help your coils slide on later, especially if they’re tight. Next, inspect your primary for damages you
may have inflicted on it in a moment of frustration while trying to extract it. If there are scratches
or gouges, try to isolate them from the other wires, and then paint them with fingernail
polish or glue or something so they don’t short. Lay the windings back down and glue
a snippet of paper over that edge or hide your failures with a piece of tape. Next, if it matters, you should be able to
tell by the weight if your primary is aluminum or copper. Most are copper. Aluminum will
seem very light in comparison. Both can be any color on the outside, so if you want to
be sure, cut one of the terminals off and see if the wire is copper or aluminum colored
through the inside. Aluminum is 40% less conductive, so it will carry only 60% of the max amperage
of copper the same size. This may matter for your project. Sometimes aluminum primary wire
is oversized to compensate, but not always. And unless you feel like wrapping a whole
new primary or finding another microwave, there’s nothing you can do about it. Your
new secondary does not have to match the material of the primary, you can wrap whatever you
want regardless. Just lower your expectations if you find, and decide to use aluminum. Then, consider your application. MOTs are
built cheap and inefficient. They waste 20% of their power, and if you’re keeping the
magnetic shunts out, they’ll waste a whole lot more and even need a fan running constantly
to cool them unless you make some upgrades. This only matters if your project is limited
by transformer heat or duty cycle, which many high power devices will be, or if your home
circuit is being maxed out, which it might be, or, if the MOT will be in continuous use
and a couple hundred extra watts all day would notably impact your power bill. If you do want to do something about it, no
other tutorials mention this, and it’s not necessary, but you can cut that waste heat
by 85% if you simply add extra turns to the primary. Up to 30 extra turns more will yield
noticeable improvements, but even 10-15 extra can eliminate the majority of that loss. But
note that doing so has the following chain reaction of side effects. 1 – It changes the
# of turns on the primary, so it will lower the voltage on the secondary unless you compensate
by adding more turns there as well. 2 – A bigger primary usually means less room for
the secondary. 3 – Because the secondary now needs more turns, and has less space to put
them in, your wire size has to shrink. 4 – Those thinner wires can’t carry as many amps without
overheating, which what we were upgrading to avoid. The tradeoff is generally beneficial, so I
suggest you add extra turns if you have the ability. Otherwise, this is one of those situations
where you might want to put the shunts back in between the coils. They kind of compensate
for it in a different, and inferior way. The primary’s wire will generally be 14 or
16 gauge, and if you’re careful, you can just cannibalize another MOT primaries for wire,
and solder it together. If you have another MOT project where you’re not re-using the
primary, that would be a good candidate. To add extra turns you’ll need to find the
terminal that’s connected to the outside winding on the coil, join the new wire to old one,
and continue wrapping in same direction. You can cut that terminal off and twist the wires
together, but it’s easier to just solder your new wire onto the old terminal. To do so, you need a source of heat like a
soldering iron, gun, or a lighter and some solder. Even though the wire looks bare, it’s not,
it’s covered in enamel insulation. You need to sand or scrape off the last inch for the
wire to conduct. I find it’s easiest to add some solder to the terminal and wire separately
first, so you only need to re-heat it later. When the wires are joined, continuing coiling
in the same direction. If you have extra space between the coil and core, you can fill that
first before coiling a new row or two. More on how to coil, coming up soon. When you’re done, cut your wire and cover
the old terminal with tape, glue or silicone. The new wire end replaces the old terminal. 2. Coil Winding Speaking of wires. You have 3 options for wires. You can use
enameled wire. You can use normal hookup wire that you purchase by length at the big home
stores. Or you can use bare wire and insulate it yourself. The best option, and the only option for smaller
or high voltage wires, is enameled wire because the insulation only adds 5% to its size. But,
most of you will have to buy it and the heavier stuff you can only find in electric motor
repair shops. Even if you can salvage it, using recycled wire is risky especially for
high voltage because cracks and scrapes in the enamel are hard to spot and will allow
electricity to arc and short the windings. If you’re going this route and you do find
any scratches, touch them up with fingernail polish. The next best, especially for thick wire,
is to buy or salvage bare wire, or strip some junk wire, and then cover it with either heat
shrink tubing or teflon tape. This is actually cheaper than buying insulated wire and better.
You’ll want to buy your heat shrink on a roll, not the cut up 6″ pieces, and it only costs
about 20 cents a foot from your favorite auction website. Put the heatshrink on BEFORE you
coil it. Heat shrink is good for 125’c, and its much thinner than the insulation on hookup
wire. Heatshrink might only double the bulk of your wire. Teflon tape is in the plumbing
isle. Half inch wide is the most common, but buy the widest you can find. It’ll mean a
lot less wrapping and fewer bending issues. When you teflon wrap, overlap at least half
of the previous turn, both for thickness and so gaps won’t appear when you bend it around
a corner. As a last, but sadly most common resort, you
can use hookup wire. The insulation is so thick you can reuse old wire from commercial
renovations or wherever, without much worry. Just make sure you measure on top of the insulation
when sizing and don’t just read what it says for the copper size, or your wire won’t fit.
But here’s why it’s troublesome. These are two coils I’m rather proud of. They’re
tightly wrapped and they fill the core just about completely. But if you do the math,
even though my fill rate is about 65%, if you only consider the useful copper conductor,
it’s not even 20% filled. That’s turning for example a 1000 watt transformer into one that
can only support 200 watts on a continual basis without overheating even when fan cooled.
The insulation more than triples the area of the wire. That means a bunch of bad things:
1 – I’m wasting most of the size of this transformer. 2 – My copper conductors aren’t nearly as
thick as they could be and they’ll overheat much quicker. 3 – The low-temp insulation
tends to melt, and 4 – The insulation is so thick it prevents the copper from cooling. But, just know the limitations and use what’s
available. For intermittent use projects that need high power pulses with long breaks between,
like some welders, hookup wire can be okay. But it wouldn’t be appropriate for a battery
charger or inside a stereo, something that stays on for a long period of time. When wire sourcing, pick whatever has the
thinnest and highest temp insulation, all else equal. For low voltage purposes, insulation
only needs to prevent copper from touching, so any wire that’s not outright bare has plenty.
Remember you have a max total wire size including insulation, but for us anything thicker than
paint is useless, you want as much of it to be copper as possible. To estimate how much wire you need, make one
big loop out of string or scrap wire, measure its length, multiply it by the number of loops,
and then add a couple feet for hookup. That’s estimating high, but you don’t want to end
up short. If you’re too lazy to estimate, it’s about one foot per loop, but, don’t complain
to me if you run short. If you have trouble getting thick enough wire
but have lots of wire 2/3 as thick, just wrap two identical thinner coils and connect them
in parallel. It’s analogous to needing a 2×4 but using pair of 1x4s glued to each other.
As long as the coils have the correct turns count each, you can stack up as many as you
can fit. Bobbins/Spools Once you’ve got your wire, you’re ready to
wind it. Now if you didn’t separate the E and I pieces,
you’re going to have to thread your wire all the way through, back and forth each time,
and you’re going to struggle to get it all in square and laying flat. When it starts
getting tight, you can use a screwdriver to help squeeze the last few turns in. It’s not
so bad for the very low voltage projects, but for higher voltage ones it’s practically
impossible. For example, if you had even just a 60 volt
secondary, you’d be pulling 60 feet through, then 59.5 feet back, just to get 1 turn in.
Then 59 feet, and 58.5 to get the 2nd turn. By the time you’re done, you’ll have threaded
1800 feet of wire. Higher voltages are even worse. For example, your original 2000 volt
secondary would’ve had you pulling a million feet of wire. And even if you could do it,
the wire would have snapped from being work hardened, and the insulation would have been
scraped away to nothing. It’s not so bad for small voltages, but trust me, just spend the
ten bucks on a hacksaw and do it the easy way. Everyone with their core disassembled will
want to make a spool, or bobbin to coil the wire on before transferring the coil to the
transformer. To make a bobbin, first measure the center
column of the core. Add a couple millimeters to the internal measurement so that your coil
doesn’t end up too tight, and add at least a pencil’s worth to each side of the external
measurement, if not more like a half inch. The extra space outside will prevent the corners
from rounding and will double the cooling. Then measure the height of available space,
and cut this block out of some scrap wood like a 2×4. If you don’t have any scrap wood,
go to a place that sells lumber, and find their cut room. Ask if they’ll give you some
scrap. Next you’ll need sides. Cut them out of plywood
and make them 1/4″ oversized. If you don’t have any scrap plywood, try the cutroom again,
maybe sacrifice a dollarstore clipboard, for science. If you want to get fancy, cut a piece
for a handle and buy: a couple long bolts, some lock washers, nuts, more scrap wood,
and use them to create a winch. Like this. Then you’re ready to start wrapping. Wrapping The most important thing when wrapping, is
to make sure your wires are tightly packed and straight through the core. Outside the
core surrounded by air doesn’t matter as much, but inside the core need to be perfect. If
it’s not, you won’t fit your turns in. Note that you want to attempt hexagonal packing,
laying each new layer into the previous groove. Not square packing, where the gaps are slightly
larger. Before you start, put some thin cardboard
strips or tape on the outside edges, to prevent the coil from shifting when you’re done. If
your project doesn’t have an exact voltage and thereby turns target, mark on your bobbin,
where the edge of the core will be so you know where you’ll have to stop. Add a notch or screw and wrap the wire on
it to anchor it, and begin wrapping from the outside. For thicker wire, counter-intuitively,
make sure you kink each wire at the corner outward with your thumb before it passes through
the core again, so that it lays flat. You can pull as hard as you want like this, but
it unless you kink it, it will always bulge in the middle. Make sure all your core passes are horizontal,
not angled, or you’ll lose a row every layer and the wire will bunch up. Instead, make
all your angle changes on the outside right where you started. When you’re done, slap a big piece of duct
tape on the coil so it doesn’t shift on you, then tape down the cardboard strips. Unscrew
and slide off one side of the bobbin, holding the coil with your hands in case it tries
to spring. Hold the coil on the edges with your fingers,
and push the rest of the bobbin out. Now would be a good time to ziptie the coil or add extra
tape. You might even want to ask for help so you never have to let it go. If the coil
shifts you won’t get it back together tight and you’ll be inventing new curse words starting
over. Be careful when test-fitting the new secondary,
insulation rips and cuts very easily on the corners of the core. If you’ve done everything
correctly, the coil should fit onto the core. If not, either your math was wrong, or your
measurements were wrong, or you lacked basic motor skills. Either way, you have to choose
whether to accept the lower voltage of howevermany loops did fit, or, start over. But before
starting over, here’s a couple things to try. First, if you can see that the problem is
that the coil is too rounded, try crushing the coil slightly with a wood-lined vice or
mallet a little at a time, and see if you can get it to fit better. Second, if you have
to take off a layer of windings, try clamping the core back together and threading as many
extra as you can through whatever gaps you can find. 3. Reassembly If everything fits, you’re ready to reassemble.
If you have room, glue some cardstock like this to the inside of the core to help insulate.
If you’re using enameled wire, always do this. It doesn’t matter which way you put the coils
on, but most of the time I like to have the terminals of the secondary on the opposite
side of the primary. Generally my power plug goes out back, and whatever the project does
happens up front, but another reason I do it that way is that I like keeping the terminals
away from each other so they can’t short. To reassemble the core, the E and I pieces
have to be touching. They don’t require an electrical connection, since a transformer
is a magnetic device, but they do need to fit back together with no air gap. The best
way to lock the core back together, if you have a welder, is to tack weld the 4 corners.
Don’t try to reweld the whole seam, it doesn’t help and will cause problems with eddy currents.
If you don’t have a welder, and I’m guessing most of you won’t, just use some silicone,
GOOP, zipties, or hose clamps. As long as its touching it doesn’t matter. The only problem
if you don’t get it solid enough, is noise. Remember this? Even after you secure the core, the coils
will also rattle, so it’s a good idea secure them with wood or cardboard shims. If possible,
at the same time as you’re securing the coils with shims, try to leave room for airflow.
Old transformers used to be submerged in beeswax when they were complete, to hold everything
in place. Modern transformers are usually vacuum pressed or dipped in several coats
of varnish. Securing all surfaces with silicone works well too. This not only cuts down on
the noise, it will prevent the coils from scraping and shorting out. And there you have it. Everything you need
to know to turn a recycled microwave oven transformer into a high power transformer
of your own design. Bonus Autopsy Before you junk the microwave, take everything
else off it. Most of it will come in handy for future projects. Power cord, fan, and switches are needed for
almost every project. The cap, magnet, triac, optocoupler, relay, motor, feet, and even
the sheet metal on the frame can come in handy for others. Now that you know how to build your own transformer,
you’re ready to make all kinds of fun, high power projects. First up in my next video is an easy and popular
one, a spot welder!

100 thoughts on “Easiest MOT Salvage Tutorial Pt.3

  1. I am prototyping a 12vdc, 200 wrms output into 4 ohms audio amp made from microwave parts using no caps, circuit boards or solder! If anyone is interested…

  2. Hi Matt here is a video I made to show you my idea to make the winding easier and also an idea for some good source for high quality wire to achieve the highest amperage. Your video is so good, I felt I had to give you something in return so here it is https://plus.google.com/u/0/photos/115722038923057297195/albums/6022877466302887841/6022877469083515682

  3. This question may have already been asked, but what is the output voltage of the transformer you built. and By the way. I found this series very educational. Great job in explaining everything. If I knew where you lived, I'd take you out for a beer.

  4. 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

  5. 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

  6. Matt you REALLY do awesome stuff. Although I do wonder how to reuse the wiring from a secondary coil to make a new secondary coil with fewer turns. (Basically i just wonder how to clean all the enamelled insulation, if even necessary)
    Anyway, your vids rock, and since I've studied a fair bit of physics and maths I appreciate the fact that you also try to teach others how to use it for something good.

  7. 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

  8. 16:15 did you frankenstein 2 E blocks together?

    I have 2 mots with identical dimensions, and I was thinking of doing that and just linking the 2 secondaries and extra primary in series for a >4kV mot.
    Gotta get the coil rotations right though.

    There should also be extra space for additional turns on the primary due to losing 2 sets of the extra low voltage coil plus 1 set of magnetic shunts.

    Common sense is telling me to go for it, anyone see any issues?

  9. 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.

  10. 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!

  11. +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?

  12. Hey Matt! thanks for your reply! I got some more transformers from my local electronics repair shop for about $5 each…Do you feel its a good price? I finished winding 10 Gauge stranded insulated copper wire on 2 MOTs. 3rd and fourth one is yet to go now… I did parallel the windings of the primaries and got 16.8 volts in series combination of the secondaries.Each secondary has 8 turns of 10 Gauge wire. I need 35-36 volts minimum for the arc to be good right? Pls mail me leisurely on [email protected] … Bye!

  13. Alok – In G+ you've set "Who can reply to my public posts" as something other than "anyone", so I can't reply to you. Umm, $5 isn't a great price, usually they're free, but, not a big cost. 35-36v is probably high, you could get away with 24-30, but, you use what you got. That 10g wire is going to melt in seconds, even with 2 MOTs, so just keep that in mind, you'll have to use short duty cycles. LOTS AND LOTS of fan cooling. Use the microwave fans and build a box around them as a tunnel for air.

  14. Im getting 39-40 v with 4 transformers , I wired them in parallel and even a 20 Amps fuse blew off. What do I do now? Should I wire the primaries in series? or make the Grant Thomson's Scariac to limit the current? Pls guide me. kindly mail me on [email protected] if possible.

  15. Alok – I'm not going to troubleshoot privately. If I'm going to say something, it'll be here where at least other people can learn from it. MOTs run ~1000 watts. You've got 4, so that's 4000 watts. Maybe more if you knocked out the shunts. Yeah, that'll blow a breaker. Nothing you can do. Primaries in series would cut down on losses, but also cut your power in half. Scariac is one way to go, but it's a bad way. A beefy light dimmer is cheaper and easier. I have a couple other ideas but they're not explained quickly. Also, those limit the power when you weld too fast, that is not your problem, your problem is that you cannot supply the amount of power you need to weld. 2.5mm might work, but I think you can find.. ~1.6mm sticks as the thinnest size. That will make a big difference. You can also wire your MOTs to separate plugs, and plug them into different circuits in your house on extension cords. Not just separate outlets, outlets each on a different breaker.

  16. So… I tried to add More Winding to my primary. The original Had 133 Turns and I added 17 To make it 150 for better efficiency. But When I plugged it in It got really hot and smoked, It even Burned though the zip ties. Now The Secondary wasn't hot. It was only the Primary. I used 16 Gauge magnet wire. Any Idea what i did wrong? Please help

  17. 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?

  18. 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??

  19. 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.

  20. Quantas vezes vc rebobinou o primario e porque , vc tambem desbastou o transformador para aumentar o espaço para o primario não perder voltagen e ter perda de voltagen amperagen coreto , e qual o fio em que vc utilizou para as espiras ou para enrolar email= [email protected], grato

  21. 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.

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

  23. Hey Matt
    I want to know if I use enamled magnet wire to make secondary, what would be the best gauge for 24v and upto 50 amp

  24. Enjoyed this series.   Thanks.  Good job.But your advice to wind an outer coil in the grooves between the wires of the inner coil is misleading, as are your drawings that show the same.  That's an impossible task.  Each successive layer is coiled in a different direction so that each wrap must cross over the top of the wires below it and you can't stay in the grooves.  You must have know that and just chose not to address it.  Best to just wrap as tightly as possible and deal with what you get.  An occasional paper wrap between layers helps level the surface below.

  25. 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)!

  26. could one just take the primary from 4 matching MOT's and double them up/stack one on top of each other inside the "E" of 2 MOT's to avoid having to wrap any coil whatsoever? trying to make an arc welder and can't seem to "learn" any of this for some reason, its frustrating as I can see it's "simple" math & science…thank you for any help

  27. 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)

  28. 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 🙂

  29. been doin shit like this for years. This vid is perfect for u toobers… I see many more subscribers in you future. good luck

  30. 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.

  31. 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.

  32. how do you calculate the best number of primary windings to make it the most efficient? i'm in europe and i want to make 230v to 115v transformer so 2:1. what's the formulas for calculation the efficiency and wattage at a certain amount of windings with a certain size of transformer core? i can't seem to find this information please help.

  33. 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

  34. MY Modified mot is heating up quite a resonable amount in like 30 seconds…is this normal/?? Do all tranformers heat?

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

  36. 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.

  37. i am planning to make an isolation transformer with MOT, If i take primary coils form two different transformerts rated for 240v and put them in same tranformer core will it be a good isolation transformer and will the ratio be 1:1 as in your video @ 2:05

  38. 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)

  39. put a BREACKER in your montage, bettwen your 120 Volts entrance and your modified transformer, … in case if your BREAKER BOX is too far, or innacessible 😛

  40. 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

  41. 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?.

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

  43. 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.

  44. I used 4 MOTs . Primaries were connected in parallel to 240 V supply For secondary winding 16 mm^2
    copper cable was used . Secondaries in series giving an open circuit voltage 25 volts.

    When I try to weld (12 SWG ROD ) the welding rod gets attached to the work piece and the the welding rod became red hot and I had to forcefully pull the rod out. But sometimes I can weld.

    1.What is the problem.
    2.Is 25 V enough for welding ?
    Should I increase secondary voltage using 10 mm^2 cable. ( The primaries are drawing power from switch board via a 25 A circuit breaker)

  45. You must be related to "This old Tony" or are you really "This young Tony" before you got old? Anyways good info and comedy

  46. 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?

  47. 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?

  48. 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???

  49. 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.

  50. 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?

  51. 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?

  52. 1)
    Rewind secondary transformer to a gage 10 ground bare cooper wire coated with fireproof GE silicon ( mix with mineral oil to thin it down like paint ) 110VAC to 17VAC… So say my circuit breaker is 10amp. Max watt I will get is 110CAC x 05Amp = 1100Watt
    Going through microwave transformer 1100Watt/17VAC=65amp

    I will need to purchase a Full wave rectifier that can handle 65watt. Correct?

    Purchase a Buck/ Boost converter for precise volt output. This DC to DC converter will also need to handle 65Watt correct?
    (( this step seems a waste of energy, as every transformation of energy from AC to DC to DC to AC chopping back to DC, it loss energy in heat, is there a better way around this step ? ))

    Then connect to capacitor. What does this capacitor capacity need be? What size of capacitor should I purchase?

  53. Again thank you very much to pass on these important power conversion knowledge. I had to read it few times to absorb it.

    So basically for my 18 voltDC tool need:

    1. Rewind transformer with gage 8 house wire to convert 110Vac to 17Vdc likely 14 turns. This will provide max 65 amp for power tool draw. But I can check voltage with my 10amp multi meter. before load. Correct? Because only when tool is running. Will withdraw more then 10 amp.

    2. Need to find (4) 100amp p/n type diode from alternator. How can I check to see if diode is still in good working order?

    3. DCDC converter. This part just fine tunning DC input like how many turn on Transformer does right?

    An alternative to this DC DC converter. I could connect end of 17Vac output to a longer bare alum wire. Just by adjusting the length clip end on this bare alum wire. I could adjust the Voltage correct? By doing so, per prior message, the volt and amp will adjust accordingly up and down. Not a smart wiring. The closer clip is to transformer end the closer to 17Vac… Is this correct thinking?

    Is there an alternative way then purchase this giant expensive capacitor? Can a bucket of 5 gal water mix with Epsom salt provide a same function? The more Epsom salt the more conductive the more volt it can store. Like ancient egypt battery.
    Can a used car battery provide smooth out sin wave function?

  54. The universal motor is a type of electric motor that can operate on either AC or DC power and uses an electromagnet as its stator to create its magnetic field. It is a commutated series-wound motor where the stator's field coils are connected in series with the rotor windings through a commutator.

    On your prior message. U indicate bosch DC power likely is a universal motor. Which I think it is as it only has 2 magnets. Is universal motor same as 2 phase motor?

    From the above—- operate on either AC or DC power…

    If this is a case. Why do I need diode or bridge rectifier to convert power source from AC to DC?

    If above is true, all I need to do is convert 110vAC to 17vAC on Transformer skip all other steps?

    What will happen connect 18vDC power tool on 17VAC with high current?

  55. For a 18Vdc Bosch circular saw to cut 2×4 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.

  56. Thank you so much. I will go back to understand the capacitor part. I did not know the smallest capacitor has to be no less then voltage used on the tool.

    My tool does not say any wattage. Only say it 18vdc the other one say 24vdc. I call Bosch company. They are not able to tell me anything more then I already know.

    I remember that turning thing inside the Bosch tool is about less then 2in diameter. So have to do some educated guess.

    Lawn mow is 120vdc x 12amp = 1440Watt divide by the surface of turning thing, diameter = 4 inch
    4 x PI x height (6 in) = 75.36 sqin

    1440 / 75.36 = 19.10 watt per inch

    19watt x Bosch cylinder surface
    ( 2 PI x R x Height = 18.84 sqin)

    18.84 x 19.10 = 360 watt

    Is this the right methodology?

    360 watt / 17 volt = 21.17Amp

    So my peak amp draw will be less then 25 amp… Which I could just utilized my none working electric lawn mow FWB rated at 25amp…

    Just need to scrap my lab top charger capacitor tonight to see if it is rated more then 17 volt.

    Thank you so much explain it. Do you also have a power supply for your battery power tool?

  57. 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?

    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?

  58. I found my old car radio amplifier (2) 2200uFx35V. + (1) 2200uFx25V

    If parallel 4400 uF 35V
    If series 2300uF 70v

    If add
    2200uF x 35V + 2200uF x 25V
    Series = 2200uf x 60V
    Parallel = 4400 x max 25V

    Is this correct, work like battery

  59. Nice video. But if you want around withn 60volt without separateing E and I. Make tap after each 10 turns so we don't want put entire coil length each time instead only need length for each 10 turns. Then use rotary switch so you get a wide range of voltage.

  60. Hi man!!!I'm impressed!!! Amazing tutorials!!! Congratulations!! Now, I'd like to ask you something: How can I do a transformer with secondary of 38-0-38 volts/10 amp and primary of 115 volts? Which will be the procedure? Thanks for you videos!!

  61. 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?

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