Instructables

Microwave Oven Transformer High Voltage Rig

For my first Instructable, I decided to make a high voltage power supply out of 2 microwaves. The videos should give you good idea of the final product (I'm using only one of the 2 transformers):


 
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Step 1: Disclaimer

Picture of Disclaimer
This circuit gives off more than enough power to kill you. I am not responsible for any injuries you may get from doing the following steps.

Step 2: What You Need

Most of the stuff you need will come straight out of a microwave, so see Plasmana's instructable, but you will need:
  • 2 Microwave transformers
  • 2 Safety switches
  • 2 125V 15A fuses and holders
  • 2 Grounded plugs
  • Random wires that you can get out of the microwaves
  • Something to mount the stuff onto (I used scrap 2x4)
  • At least 2 friends - one who knows CPR and one that can call 911 NEVER DO HIGH VOLTAGE EXPERIMENTS BY YOURSELF

Step 4: Wire it Up

The circuit will be wired in series, giving you an output of about 4kV. I decided to use 2 plugs to make sure I don't set the wires on fire :D. You can wire the rest up according to the schematic below, if you can't read it, you shouldn't be making this. To get out the most power, attach the 2 HV Out wires together and touch them to ground. Tip: before attempting to ground anything, scrape off enough varnish to have a good connection. Caution: This setup is un-ballasted, and the transformers can heat up very rapidly. Use this only for short periods of time.
Xylit0l2 months ago

Use class 1 gloves minimum if you plan to build this

I believe you wired this wrong. to wire it correctly you must connect the cases together and ground it then arc between the 2 HV out wires. if you want more power you can wire 2 microwave oven transformers in series as a half-resonant circuit or better yet wire 2 in series in parallel with 2 more in series and connect them like this:

:
F2MJC48GW88L8V9.LARGE.jpg
Ignore the PFC capacitor you don't need it to work. The ground connection is in the middle. As I said before connect the cases of the transformers together and ground them. draw arcs between the 2 HV outputs.
gobitz4 years ago
I suggest using something more HV proof than a piece of 2x4. Wood can conduct electricity and I have gotten an MOT to arc off a dry piece of wood and concrete!
concrete is actualy a conductor a poor one but it dose conduct it is used in alot of higher wattage resistors
modog40003 years ago
how do you build a ballast
http://www.instructables.com/id/Home-made-ballast/
HVahead HVahead2 years ago
nvrmnd thatnot an actual instructable...
muttyfutty4 years ago
I currently own an MOT and it is working fine, except for the fact that the primary windings get very hot during operation (after 10 seconds of arcing) I am connecting it directly to the Mains (240V) I have mesured the imput (Mains current) to be 10A ++ Is there any way to limit the input current to prevent heating in the secondary windings On another note, is it possable if I had 2 MOT, to connect them in Parallel in order to get greater ampage output, and if so how Sorry for the long question! :) Thanks in advance! Mike
DevCoder (author)  muttyfutty4 years ago
The reason your primary gets so hot is because the MOT isn't ballasted. See step 6 for a schematic. Also, it is possible to get 2x the current, connect them in parallel like the schematic in step 4 (use the transformers bases as the other HV out)
Thanks, Prob is that I only Have 1 MOT, is it possable to current limit by putting a 150W light bulb in series with the primary? Thanks
DevCoder (author)  muttyfutty4 years ago
you can, keep in mind that a MOT usually uses 1500W of power, the light bulb would be decimated.
I've got an 150W halogen bulb. will that work or do I need a larger value? what do you reccommend?
DevCoder (author)  muttyfutty4 years ago
i still recommend another MOT, just go dumpster diving a little
Thanks, still trying to get that MOT. but I have saucessfully used a 2200W kettle in series whith the primary, NO HEAT!!! yay! but the water in the kettle starts boiling everytime I arc it lol
DevCoder (author)  muttyfutty4 years ago
LOL! You should make some pasta with it :D
yep, pasta and high voltage, a pretty good combo (what about the sauce?)
use the arc to "euthanize" a crab or two and make a bisque
wow!, I never thought of that...
Problem is that when I use the kettle as ballest the arcs are reduced to about 1cm as opposed to the 15cm ones I got when ran with no kettle..
Yeah, I tried ballasting one of my MOT's, sure it stops it from overheating but the major downside is that you get tiny arcs. that's why I don't normally ballast. I just use a powerful fan from a microwave oven to TRY and cool it.
bryanb3334 years ago

a cool thing to try with this is clamp a penny to one output and a nickle or some other metal to the other then make the arc.... half of te arc will be one color the other half a different color alsotr somthing gold plated if i remember correctly you get a bright white core whit a bluish sorta flame the pennies will be greenish ... lol we did this in my electronics class in high school :D

BobS bryanb3334 years ago
copper,  nickel and other heavy metals used in coins form very toxic fumes when vaporized. Even welding of zinc plated steel without fumes being extracted is very bad for the lungs.

toxic like disabled toxic, or dead toxic, not just cancer or COPD toxic!!
bryanb333 BobS3 years ago
Also Note that whenever and arc is present you are actualy creating O_3 which is also poisonous it can cause sufication or something along those lines the molicules are larger than ur normal O_2 molicule
ewh, metal smoke! don't breath this!
Haha! "Will it blend? That is the question" I love his shows
hahahaha me to
jbyrns19933 years ago
I have a MOT that I am afraid to plug in, even though I have experience with 20KV. Is it possible to re-wind the secondary to give high voltage but very little current? I want like 20ma or less.
DevCoder (author)  jbyrns19933 years ago
The thing is, at only 2 kV, a MOT won't jump the air to your hand. Even so, I either wore a pair of 3 mm rubber chemical gloves or attached the wire to the end of a long wooden stick. You can rewind it, but you would be winding it with wire thinner than what is currently on there, and you would have to wind it many, many more times. Basically, it's not at all worth it. Instead, just take all the safety precautions you can.
Highjump444 years ago
 can u explain the stick 
 and wat two contacts is the spark jumping from
 pin 10 hv out and ground right    
 but wats the stick for,    pressing the switch and moving some metal thats connected to ground and the terminal of pin 10

The stick is an insulator, meaning elecricity does not move through it.  It ensures that the electricity goes through the termanals, making a spark, instead of through his body and heart, causing a heart attack.
The stick is used so the author can touch the wires together with out burning or electrocuting himself.
rimar20005 years ago
This is very good work, but look http://www.instructables.com/id/Build-a-Microwave-Transformer-Homemade-Welder/

Seems Tim Anderson said you...
DevCoder (author)  rimar20005 years ago
While I do admit I got some of the ideas from that Instructable, the similarities end there. This setup gives off around 2kV at a low amperage (if anyone knows the amperage, I would love to know it), while a welder uses a relatively low voltage at a very high amperage.
like xellers said, these transformers put off a crazy amt of amperage. 50 mA from one hand to the other is enough to kill you, and MOTs put off abt 500 mA depending on the wattage of the Microwave u got it from.. if u got a shock from say one finger to the other, it could seriously injure your hand, but chances are u'd survive it. but even then high voltage is a completely different animal.. you could be grounded somehow, touch the wrong wire and BANG 500 mA straight to ur heart..
I agree!
I did more mesurments and descovered that the 2KV reduced to 500V at 1.5A when pulling an arc...
For some reason my MOT sucks in about 10+ amps (my ammeter goes up to 10 only) and puts out 1.5A Woh!
LOW amperage? The 500 - 100 ma that these MOTs output is more than enough to ensure that you drop dead the moment you touch those wires.
the amperage in 500ma
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