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Microwave Oven Transformer Stack

This is my Microwave Oven Transformer stack. It is currently current limited using a heater.

There is approximately 10 36 watt 4' fluorescent tubes in a string around my garage that I am lighting with the MOT stack .

My MOT stack contains 4 Microwave Oven Transformers connected with their outputs in series and their inputs in parallel. They are mounted on plastic cutting boards. I am using threaded rod to hold the layers in place while the PVC pipe covers the threaded rod and it also supports some of the weight.

The output of this is approximately 8800VAC at 350mA The Input voltage is 240VAC

Thanks for looking, Please comment and remember to rate if you like it!

Just say if you want any pics of a certain thing, e.g. the MOT stack arcing to wood/metal etc. (I will try to get more pics of it arcing soon but it is hard to use a camera that has like a second delay before it takes the actual pic from when you press the button, stupid camera) ********************************************************************************************************** Edit The new pictures are of an arc between two carbon electrodes. The other pictures are of 12 fluorescent tubes connected in series but arranged in parallel so you can see them all

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crazy-blender says: May 7, 2013. 8:46 PM
Could you please make a step by step
Hydroelectric says: Dec 1, 2009. 1:11 AM
Nice work with the MOT building Thermo. Hope to see it connected to the telsa coil at your building. I also like the pics of all of the light s connected together. GOOD JOB!
thermoelectric (author) says: Dec 1, 2009. 1:15 AM
Haha, Thanks. I hope to have a Tesla Coil built by the end of the holidays, But wether or not it will happen is a mystery. I know my MOT stack is tough, because after I took it to school, I felt like taking it down teh steps, on the trolley thing, It fell off. and fell about 10 steps (concrete), And I didn't notice any damage at all.
Hydroelectric says: Dec 1, 2009. 2:17 AM
How was the reaction of your class when you showed them? Dam , that must be pretty tough.
thermoelectric (author) says: Dec 1, 2009. 2:24 AM
They were pretty amazed... After that, our science teacher showed us a vandegraff generator, really puny sparks compared to my MOT's...
Hydroelectric says: Dec 1, 2009. 11:23 PM
Lol, your's compared to the vandegraff generator, I think that your's would win by a long shot. By that I mean in spark disposal ofcourse.
Plasmana says: Oct 3, 2009. 9:40 AM
Man you did a good job! I wish I had more microwaves to salvage for their transformers.. :P
thermoelectric (author) says: Oct 3, 2009. 5:33 PM
Thanks Plas, I will hopefully be submerging them in oil so I can run them with a bigger ballast, so I can get sparks like yours :-) It took about 4 trips to the tip (dump/waste disposal etc.) shop (they put things that people might want that was sorta in the garbage up for sale. I had mostly one each time, but sometimes I scored good and got 2 microwaves. (I have 5 MOT's all up), one that is going to be a ballast.)
Plasmana says: Oct 4, 2009. 4:58 AM
Nice, I only use one transformer for voltage and the other as an ballast. Those huge arcs I got in the end was completely unexpected, I never knew why those arcs are huge. Until some helpful guy told me why...

Quoted by HighVoltageScience
The burned out sparkler make bigger arks cause
the burned part is a insulator and the wire is a
conductor that makes a capacitor and make's
bigger arks.

I don't know how to describe it in non technical form, so you will have to figure it out.. :P

I am (hopefully) going to the car boot sale in about a week, I might find microwaves there :-D
thermoelectric (author) says: Oct 4, 2009. 9:47 AM
Wow, The sparklers are capacitive? You might have been achieving near resonance with the MOT's, Because that can give you monster arcs
The Ideanator says: Oct 14, 2009. 5:06 PM
Oh, if I used that circuit, would it make for a better MOT based welder?
thermoelectric (author) says: Oct 15, 2009. 1:28 AM
Maybe, But it would be harder to get caps rated for the amperage, Idon't think it would be worth it, but that is just my 2 cents
Plasmana says: Oct 4, 2009. 10:55 AM
Yeah, I thought so... :-D When i get a chance, I am going to add two microwave oven capacitors to the circuit to get the transformer to it's resonance to make big arcs. BTW the link you gave me is blocked.. (I am at collage) So I won't be able to see it untill I get home which will be about a week. :-( I might forget it by then, lol
crazy-blender says: May 7, 2013. 8:46 PM
Use HTTPS
thermoelectric (author) says: Oct 4, 2009. 1:47 PM
Have you tried using a proxy to get onto the sites? Have a look at the list here and try inputting that link I gave you. Look out though, because if your collage techies will probably start to block them, if they haven't already done so
Plasmana says: Oct 5, 2009. 11:16 AM
That is also blocked, lmao Is there some kind of code that I can download onto my usb key back at home and take it to the collage computers to get some sites unblocked?
thermoelectric (author) says: Oct 5, 2009. 1:39 PM
Hmm, I don't know if there is some kind of code to do that, sounds like your collage has some tight filtering. How about a forum topic?
Plasmana says: Oct 5, 2009. 1:45 PM
It is pretty tight, and some features on college computers are locked by admin, which prevents me to play my browser game 'darkorbit', so I came back to Instructables instead :P
thermoelectric (author) says: Oct 5, 2009. 11:18 PM
Are you using a laptop? If so why not try to make an antenna to pickup a signal from a nearby household?
Plasmana says: Oct 6, 2009. 7:33 AM
How do I make an antenna for my mac laptop? My computer is picking up something, but it is too weak to use, lol
thermoelectric (author) says: Oct 6, 2009. 1:42 PM
You can just searcl Instructables for it...
Plasmana says: Oct 5, 2009. 1:48 PM
Also, the blocker is called: MessageLabs Look it up on goolge, its popular, I think, lol
The Ideanator says: Oct 2, 2009. 7:26 PM
Holy zombie jesus! Its a thing of beauty! 8800vac?? OMG!
thermoelectric (author) says: Oct 2, 2009. 7:32 PM
Thanks :-) Yep, Sure is 8800VAC. Tis a bit less than what comes from a NST or a OBIT, But the current is sure a lot higher than those other whimpy transformers... (Gotta be careful not to let the spark touch me and make my heart do the dance of death...)
The Ideanator says: Oct 2, 2009. 7:38 PM
Yeah, that would not be the best thing in the world, I wanna see more HV coolness
thermoelectric (author) says: Oct 14, 2009. 12:39 AM
I'm trying to get some transformer oil to submerge the stack in, so I can run it at a higher current, and not be as worried about burning out the MOT's.

It will sure look more awesome when I start using a secondary shorted MOT to current limit it!
thermoelectric (author) says: Oct 2, 2009. 8:59 PM
You got it! More pics were just uploaded!
The Ideanator says: Oct 3, 2009. 9:08 AM
Sweeeeeet!
thermoelectric (author) says: Oct 3, 2009. 5:28 PM
Sure is!
The 4th Doctor says: Oct 5, 2009. 7:17 PM
i just realized, you should burn some stuff with this >=D
thermoelectric (author) says: Oct 5, 2009. 11:01 PM
What type of stuff? I'll be more than willing to do it...
guyfrom7up says: Oct 5, 2009. 5:35 PM
NICE MOT STACK You are running those in anti parralel, right? As in it's +-4400 vac around earth ground? if not, you should do that immediateley, 8800 is very hard on the insulation. I'm jealous :P Also, for those of you that are looking for microwave transformers on the cheap, your county might have a bulk waste day where people throw out stuff that normally the garbage men won't take, ie couches, MICROWAVES, furniture, etc. Over the summer I picked up 6 MOTs for free, turns out one was broken, so i turned it into a 12 volt 60 amp power supply for a 1.5 farad capacitor to cut metal through a huge IGBT.
thermoelectric (author) says: Oct 5, 2009. 10:55 PM
Thanks :-) Yes, it is 4400VAC on wither side of the dround, you can see the ground wire linking the two bottom (middle) cores in one of the pics.
Sandisk1duo says: Oct 3, 2009. 8:34 PM
cool! i probably wouldn't keep such a deadly device in my house
thermoelectric (author) says: Oct 3, 2009. 9:05 PM
Haha, It sure is cool! It is only deadly when it is plugged in, lol. Anyways there are many things that are just as deadly as that in your household, you have a microwave don't you, probably a TV too, they are all dangerous...
Sandisk1duo says: Oct 3, 2009. 9:09 PM
yes, but my TV doesn't have it's HV coil exposed i usually mess around with 300V flash circuits, they have lots of voltage, but very low current
thermoelectric (author) says: Oct 3, 2009. 9:32 PM
That is true.

What happens if you accidentally charge a small (or large) cap bank? This happens! Let me introduce you to Project Thumper!


Sandisk1duo says: Oct 3, 2009. 9:37 PM
i have a 300v 2000uf capacitor made form 30 flash caps
Plasmana says: Oct 4, 2009. 5:00 AM
Lol nice, I got one made from 20 flash caps, I use it to blow up stuff and coilgun experments. :-)
Sandisk1duo says: Oct 4, 2009. 8:42 PM
i let the magic smoke out of my charger circuits, so i have to go get more... i'll probably add another 10 or 20 caps to the circuit
Plasmana says: Oct 5, 2009. 1:32 PM
lol and the mini chargers take too long to charge the cap bank too.. So I use the MAINS for instant charging. :P Also the way I have desinged my cap bank, I can charge it up to 600v safely... Muahahah!
thermoelectric (author) says: Oct 5, 2009. 1:41 PM
I'm gonna set up a mains charger tonight, I'm just worried that i'll over voltage the 330V photo flash caps.
Plasmana says: Oct 5, 2009. 1:51 PM
I one time accadently over charged one up to 350v on 330v limmit flash cap, but it still works fine. :-) If they begin to swell or making faint popping noise, (inside the cap) then it is bad.
thermoelectric (author) says: Oct 4, 2009. 10:49 PM
I seem to let the magic smoke out of alot of my circuits too. Why not charge them with the mains (try the 220/240 outlet, current limit it with a light bulb in series ithe the rectifier, rectify it and you can charee a bank hell quick.
Sandisk1duo says: Oct 5, 2009. 6:31 AM
i have only 120v outlets
thermoelectric (author) says: Oct 5, 2009. 1:34 PM
No 220v outlets for a dryer?
Sandisk1duo says: Oct 5, 2009. 2:03 PM
oh, yes there are 220v outlets
thermoelectric (author) says: Oct 5, 2009. 2:10 PM
So if you put a light bulb in series with the rectifier and the rectifier charging the caps it will work.

light _ connection between cap bank and -
---()----------| - |-----------|

AC Rectifier cap bank
thermoelectric (author) says: Oct 5, 2009. 2:11 PM
Dang, It didn't work I don't think the light is necessary though
The 4th Doctor says: Oct 5, 2009. 7:15 PM
yeah i suppose it siphoned off too much power, if your capacitor bank isent too large there shouldent be that bad of a current surge when you charge it up
thermoelectric (author) says: Oct 5, 2009. 11:01 PM
I'm gonna try it again thisarvo. I hopw it works this time.
Sandisk1duo says: Oct 5, 2009. 5:20 PM
you'll need the light as a ballast, so your capacitors charge slower
thermoelectric (author) says: Oct 5, 2009. 10:52 PM
Ah, okay
The 4th Doctor says: Oct 4, 2009. 11:20 AM
check out these caps
http://www.bgmicro.com/index.asp?PageAction=VIEWPROD&ProdID=12865

i just got 8 of them! two freaking kilojoules! equivalent to around 400 photoflash caps!
Sandisk1duo says: Oct 5, 2009. 5:21 PM
those have a higher internal resistance, so it would take longer to discharge
The 4th Doctor says: Oct 5, 2009. 7:07 PM
meh there not so bad, got a pretty nice can crushing effect, thompson disk shooter, i hooked it up to a small coil and it freaking exploded, and im sure thell make a nice railgun but they certainly arent the fastest
Plasmana says: Oct 4, 2009. 11:48 AM
Yeah, I seen those caps, I can get em cos Im in the freaking UK! :-(
thermoelectric (author) says: Oct 4, 2009. 9:58 AM
Did you see Project Thumper Plas?
I'll link in an introduction, it has a MASSIVE cap bank
Plasmana says: Oct 4, 2009. 10:59 AM
Yeah, i saw it :P Danm, just about all the good stuff on the internet is blocked. Even instructables, I went through a lot of trouble to get instructables unblocked for me :-D
thermoelectric (author) says: Oct 4, 2009. 1:48 PM
That's unfortunate, Tell me how the proxy sites go, they used to work for me until my school blocked all of them :-/
thermoelectric (author) says: Oct 3, 2009. 9:42 PM
That's easily enough to kill you
Sandisk1duo says: Oct 3, 2009. 9:45 PM
yes, but the voltage is less then 8800VAC
thermoelectric (author) says: Oct 3, 2009. 10:09 PM
Still, It can still kill you so it is considered dangerous, although I admit having something where you don't have to touch it to strat the arc is a bit more dangerous.
Sandisk1duo says: Oct 4, 2009. 8:51 PM
if you convert the AC to DC, you will get 13200V DC
The 4th Doctor says: Oct 5, 2009. 7:11 PM
well your still getting that peak voltage before you rectifier it, but loosing half of the power unless you have a full wave rectifier and with the caps and diodes needed for that you could make a voltage quadrupler
Sandisk1duo says: Oct 5, 2009. 7:49 PM
quite right
thermoelectric (author) says: Oct 4, 2009. 10:47 PM
Wow, That sure is a lot more voltage, I wish that TC's were suited for DC...
Sandisk1duo says: Oct 5, 2009. 6:32 AM
you rectify the output voltage
thermoelectric (author) says: Oct 5, 2009. 1:35 PM
Oh
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