Thank you Mr. Murray-Smith. I enjoy the content, it is very educational. And your style of presentation is very engaging.

I worked in a transformer, choke and inductor making factory for a while. We made devices so that they didn't vibrate and make noise, to improve insulation performance, and to improve efficiency. Some of the final construction steps were to immerse the devices in a bath of varnish, in a vacuum chamber. This sucked the varnish between the core laminations, the bobbins, and all of the coil windings, when the vacuum was released. Then they were drained and baked in an oven to harden the varnish. A similar process is used worldwide, using other varnish or wax. The downside is that transformers treated in those ways are very difficult to dismantle nondestructively. We often had older transformers, made by many different manufacturers, sent in for reverse-engineering and rebuild. That could be done least destructively by immersing a device in solvent for a couple of days, and then its core could be dismantled. The first 'E' or 'T' (for either 'E-I' or 'C-T' laminations) of the transformer or choke core would be drifted out with a thin drift, and then the dismantling became progressively easier. Bobbins could then be unwound, measured and turns counted, before being cleaned and rebuilt. In the light of this, your destructive method is perhaps the easiest one to adopt, if a winding can be sacrificed.

I boiled one of the transformers in a pan and made a youtube video with that process (I wanted the core to expand a bit and the resin that holds the coils to soften). MOT s (Micro Oven Transformers) make this world a better place :D Very nicely done transformer conversion! Thank you for sharing!

They should force all kids across the world. To learn from this man. He is doing amazing things here. I learned more in a hour watching his videos. Than all of school.

Thank you, sir, for demystifying the spot welder and many other things! Stay safe!

My friend and I have been staring at a transformer for two months, trying to pluck up courage to saw into the weld. And now you come up with the [obvious when you see it] solution. Many thanks!

2 thumbs up and 5 out of 5 stars for you! Great description and very nice demonstration. You have answered the question I've always had regarding turns in the top coil and effect of putting more turns.. Thank you

This is the most practical channel to have in your subscriptions. My brother from across the pond believes in the KISS theory " keep it simple stupid" but doesn't speak condescendingly. Allways a pleasure to get the missing or improved bits from him. He makes every day projects easier. He's worth more than you can give. Thank you Robert Murry Smith.

Great job Professor Murray-Smith. Just the right amount of information to present to us, the KZfaq clients.

One of the best explanations of a transformer aswell as a demo. Brilliant. !!!!

Thank you, soo much. You are an amazing engineer. I was watching you from USA. Good job. I got a bunch of those microwave transformers. I always believe there is something that can be done using them.

Don't get no better than this! Well done sir. And thank you. Am building a spot welder as we speak.

Takes me back to the science lab at school many moons ago,you have the same passion as my science teacher,the passion is infectious!!!

More video gold. Thank you Robert. You make me feel mentally wealthy. You rock and thank you.

I watched quite a few of these videos but for some reason i like the way he demonstrated and explained everything a lot.

Brilliantly lucid Rob. Once again! Looking forward to something on Fly back transformers.

The things you can do with a micro transformer is amazing. Great vid as always. Such a wonderful man. I wish I had a friend like him.

When I hear "Do not try this at home" I say "Don't tread on me" Thank you for freeing up the information!

Your explanation of the transformer might be the best explanation of transformers I have experienced.

thanks for the video. I've watched dozens of videos on this particular subject and yours is the best that I've come across so far. Thank you very much.

I love the combination of hose clamp, boost cables and vise grips!

We were often taught as small children to test electrical batteries such as the square ones by our tongues however when using bigger electronic devices i will say this isn’t the correct way. I kno someone who actually received a large sized jolt on there tongue from this and resulted in no taste for some food. Even some smells you wouldn’t be able to detect. Over time it has gotten better but i suggest making a simple light which can detect power. As we do not all have complex electrical detectors. This is my recommendation so always use caution. Also i have found its best to use a nice size rubberized shoe to protect one from things when working with high power such as electrical plugs. Hope this helps , voltmaster.

VERY WELL DONE, The explanation was "spot" on regarding the electrical theory. And the trick to removing the secondary coil wire is going to save me A LOT of time, Thanks!!!

My old Weller soldering gun was essentially a miniature version...the secondary was a single turn of heavy copper wire. It had a separate winding for a small light. Countless uses for old microwave transformers. Great video! You probably saved a lot of headache for people repurposing these transformers.

Well done. I've seen a few of these. With your explanation I now understand. Thank you. Peace

i am comfortably numbed,you surely got that physics into me like i never saw or heard before,thank you captain.

finally someone who can explain my scraps i ve taken from my old microwaves. subbed. keep it going!

You have started the wheels in my head turning. The possibilities are endless.

Nicely done! WAY easier than the last one I did.

This is a great video! Thank you so much for the tips!! I have 4 of these mot's now. That will be much easier.

Awesome demonstration as always. Keep up the good work 👍

Thanks Robert!

Very nice work. I've done quite a few of these myself, I've got quite the box full of them now. What I do is, place it in a vice with the bottom of the "M" facing up, That's the part that's welded on. The welds are very shallow and I use an angle grinder to grind them off. The bottom section comes off then. Then I put it down on a workbench, with the side I removed facing down. I use pieces of wood, about 2"X2" and 6" long to tap down both sides of the wire windings, a few taps on one side and a few taps on the other, you can grease the metal a little bit to help it slide down. I generally remove the primary winding because I use the secondary winding in place and cut out the center section up to the winding and make electromagnets out of them. If you're going to make an electromagnet out of these (and they make excellent ones!) Then you want to cut out the center section so that you're left with a u-shape which is the best for a magnet.

Love all the projects that you come up with!

I have been using and rewinding microwave transformers for years in radio linear amplifier projects, both for high voltage supplies by lifting the grounded end of the HV winding, and also by removing the HV winding and rewiring with heavy gage wire for filament supplies. Many of these transformers are capable of 1 amp of current at 2000+ volts which is a substantial amount of current. The only downside is sometimes they can be mechanically noisy, and are not as efficient as transformers that are designed with more conventional core lamination and winding principle's. The upside is cost! They are dirt cheap compared to commercially available equivalents designed for this application

A really fine video. Useful info, to the point, and great demos. AAA+++

5:38. Very pro-active of you Mr Smith. Makes us wonder if you haven't wrestled with a plug in past projects. lol.

Another very interesting video. Naturally images come to mind of all those microwaves I took to the tip in the past. Thanks for the inspiration.

that was brilliant, thank you!

Now this is the kind of stuff I like. Thumbs up!

Thanks Robert great stuff

Thank you great work learning a lot of things always wanted to know.

FYI, there is a movement on KZfaq trying to get project videos that use MOT's banned, because they can be so dangerous, handled improperly.

That was a clever demonstration to save the iron core while getting that coil out of the way. 👏

Please be careful with those things! You of all people don't need to be told about with microwave Transformers, it only takes one time! Looks like you're having fun stay safe! 👍😆

Great video Robert but I wouldn't recommend using vice grips for holding the nail as you could melt the springs in the giver grips as well as the nail 😉

Your program is very helpful I had seen others run loops to the transformers I didn't know it increased the power Very interesting thank you Joey Cotton Houston Texas

Thanks for all the videos 😎 I would love to see what you could do with geodesic dome energy 🕸️

very nice demo

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, very nice video! Great explanation! ❤

Thanks again Robert

Another excellent and informative video thanks.

This is soo cool! I wish I had a dad like you

Btw, if you build a spotwelder out this, then it's better to use a chromium copper alloy for the tips, as it will stick less to the welded parts. Cheers mate !

Thank you very much learned so much from you and love your humor

Your channel is gold

Thumbs up as always Robert. Good stuff. The mad science Bob Ross of our times.

If you take the basic microwave transformer, and use 3 parallel microwave capacitors on the secondary wire (the other secondary wire in on the casing), and initiate an arc between two copper electrodes, you can get air to burn. Burning air is different than just a plasma arc.

The stuff of dreams. Keep them coming! dp

GREAT STUFF !

Very good stuff!

thanks robert

That was definitely cool 😎

Tnx

Hi Bob! Over the past few years, i have often stumbled on your videos, and always enjoyed them. But this one takes the cake. I was currently stumped by the EXACT problem that you explained here so nicely. In fact only a few hours ago, I rewarded a workshop mechanic with some prize money to suggest a way to remove the secondary, but he just said No, I have tried and tried, and never succeeded - they are built and sealed in the factory so tightly, it is impossible. I was planning something close to what you showed, and felt so happy for the encouragement! I have always felt that posting nice, informative videos on the net is like broadcasting seeds of help in the wind - you never know or imagine how much even a tiny bit of your kindness and effort can mean to some one! (Sorry for going on so long.) By the way I am a retired Civil Engineer, having the best time of my life, tinkering and making in my house which is more of a junkyard than a decent house! Thanks a lot for all your videos, and best wishes for every thing good in life (and beyond)!

Very interesting video, thanks

This is sort of like a cooking show. Probably won't use the recipe, but I love watching!!!

OK... you hooked me. Subscribed!

nice video thanks

There's that laugh! Really making my day! (Although I find it hard to believe that you did not expect that to happen... ;-)

Creative video, thanks for sharing :)

I don't know who laughed harder, you or me, too funny

❤❤❤ thanks mate

Tip: cut the sides off then put the transformer in the freezer overnight. Metal contracts when cold making them come out easier.

I have a collection of microwave transformers. Nice!

Very excellent, i do much with Microwave Transformers but never understud Like this time good explenation

6:30 great tip! most use 1 turn since its seems logical, but 2 turns are in practice way better. Yesterday I converted my 800 transforemer from 1 turn to 2 turns, and its amazing - like 4-5x more power. ( i use a chinese 2000W(2$) AC Motor regulator, and i can melt nails when the Potentiometer is only at 20% power)

Great vid thanks from America west virginia

Really enjoy your topics interesting and educational, superb

I keep a set of electrical nippers in the car, and when I see an appliance like that, I cut off the electrical cord and use it to make an extension, since it has a right-angle plug, that are useful for getting to the outlet behind the sofa. I also collect vacuum cleaners, and join the hoses, so I now have an 8m hose for the car. The rest is useful for radio antennas, etc.

I’ve got a Panasonic CT55JW it’s working fine apart from it’s Display, and then this .. fantastic , At least I know it’s all good parts !! Apart from the display walloped lol

It's low voltage but high amperage. Throw a clamp on the hot wire and meter the amperage when you spot weld.

Congratulations, Robert. Keep that good job going, because many will get richer in their knowledge

Very interesting!

I love your videos. Please keep up the good work.

You will find that the coiled extention might heat up your metal too. It makes a big difference to my inverter welder in its less smooth delivery if i have a wound up extention leads being used even just hanging on a nail. Quite amazing really the effect. Would be even worse effect with a old school transformer welder or one of those cheap Chinese aluminium coil types. The fluctuation would be awful to work with. You can hear it changing frequency vibration when you weld.

Good Idea for a heat resistant furnace.

Don't forget the flash joule graphene !

So could you use multiple transformers to weld with and how would you do it?

They make great fractal burners as well.

Thx. Single wrap was slow to heat. Double wrap was much faster....

I just hope nobody tries to spot weld by holding the live wires connected to Vice grips!

Love your smarts lol and when the unexpected happens lol I got a good laugh too it's good to learn new stuff or just look at it and wonder wow amazing always smile my brother cheers mate I'm from usa but knowledge is universal

You are very lucky in the UK. If I want 220 VAC, I have to run a dedicated line from the circuit breaker. That can be expensive.

I wonder how efficient one of these would be as a base for a power supply for a whole house LED power supply for exterior lights... Instead of running 120VAC around the eaves of the house for the typical LED bulbs, have actual LEDs mounted in the eaves ever couple of feet with a MOT powered low voltage line feeding all of the various LED locations...

Hands down the quickest way to remove coils from these. The first one I did I was at it for close to 2 hours!

nice video, what's interesting is that the voltage and current change together ie when voltage increases the current decreases and vice versa, this is because the iron core of the transformer causes a damping effect with respect to the magnetic field between the coils, Nikola Tesla got around this by removing the iron core with his oscillating transformer (Tesla coil) which amplifies both voltage and current, that would be a great video, building a Tesla coil :)

you look like drunk mr.bean

The MOT I pulled out was wired backwards or something. The input coil was made of smaller wires and such and the output was the larger wires, so I ended up cutting the wrong one off