Microwave Oven Transformer High Voltage Rig





Introduction: Microwave Oven Transformer High Voltage Rig

About: Devin is a cool guy, eh doesnt kill himself while doing stupid things, and doesnt afraid of anything.
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):

Step 1: 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 3: Mount Everything

Simply place the parts in an orientation so that you can wire it up easily. Then drill the transformers and fuse holders onto the 2x4 and nail the safety switches down.

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.

Step 5: Power It Up!

Carefully, wearing non grounded shoes, holding non-conductive rods to push the switch, press the switches and hold them. Don't look directly at the arc without eye protection, it is close to the brightness of a welder. You should now have a spectacular arc to show off to your friends and family!

Step 6: Random Notes

  • I purposely put the 2 safety switches on opposite sides of the 2x4 to prevent me or anyone else from turning it on by themselves. Also, to keep the board from breaking under the ~12 lbs of transformer, I made it as short as possible.

Update as of 3/5/09:
  • I decided to ballast the first transformer with the second, schematic is attached

Step 7: Update: Neater and Safer

I decided that I could find a better and more presentable base for my project than scrap 2x4, so I reorganized everything onto a piece of Formica giving me space for at least two more transformers. Also, it is more easily troubleshoot-able and modular



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    77 Discussions

    This would make a good squirrel (or other pest) trap, provided you monitored it and only connected it to administer the pentaly.

    This is also a good way to get someone killed. Even if the electricity doesn't cross your chest and stop your heart, touching any other part of your body will cause violent muscle contractions which could cause broken bones or other injuries. I won't even mention the serious buns and tissue damage it will cause!

    1 reply

    Lol... "buns damage".
    I know what you meant....it was just a funny thought.

    "....I dunno, I went outside to play with my transformer and the buns just exploded! Well just do pizza."

    -"Dude, what's wrong with your shorts!?"
    -"Doc says I got wear this bandage for a month. I was playing with my transformer and caused serious injury to my buns".


    2 years ago

    Just be aware of that the current from a MOT (microwave oven transformer) can KILL YOU in an INSTANT ! Unlike the misunderstanding that the higher the voltage is, the more dangerous it is, it's the current flow (especially at 50 and 60Hz) which kills you. The frequency of 50-60Hz is also contribuing to an cardiac arrest (atrial fibrillation) of the heart. Tesla coils on the other hand, is not so dangerous at the HV-side because even if it is hundreds of kilovolts output, the current is very low. Also the frequency is very high, and will not pass through the body but only on the surface of the skin. It can burn yes, but will not pass the heart.

    A typical MOT delivers 2000 volts or more output, and currents up to 500 mA. Ten times higher than the current necessarry to stop your heart.

    Again - playing around with MOTs requires a deep understanding of the dangers it represent. Always have another person with you when experimenting with high voltage. He/she may disconnect power if an accident occurs.

    Use an old NEON SIGN TRANSFORMER INSTEAD, MUCH SAFER ! Don't build this to play with, only if you are experienced with electricity and VERY COORDINATED. Your first mistake could be your LAST MISTAKE ! If you insist on trying this at least put SEVERAL RESISTORS IN SERIES TO LIMIT THE CURRENT IN CASE YOU DO COME IN CONTACT WITH THE HIGH VOLTAGE. Also, make sure to GROUND THE CASE (AND THE TRANSFORMER) TO EARTH GROUND. Microwave transformers use one of the HV leads connected to the transformer case which is EARTH ground in a microwave. Use many 10w or higher to total 300,000 ohms which limits the current to 5ma (1500v / 5ma = 300,000 ohms). It takes about 5ma to POSSIBLY stop your heart. Still not safe but a big improvement. Also, space out the resistors several inches, the HV will want to arc across them.

    As for putting a light bulb in series with the primary, it's a good idea but use a LOWER WATTAGE BULB. A 100w bulb would be, 120v / 100w = 1.2 ohms. Not much resistance. A 5w or 15w bulb. 120/5w=24ohms 120 / 15w - 8 ohms

    I would use the 5w myself, ONLY INCANDESCENT WILL WORK, Fluorescent or CFL will probably just burn up.

    If you aren't EXTREMELY CAREFUL use a neon sign transformer, you can get MUCH HIGHER VOLTAGES much safer. Or a TESLA COIL.

    P.S. The average microwave transformer can put out AT LEAST 1A, possibly 10A or more upon shorting. Wear sunglasses if you need to look at an arc or WELDING GLASSES if you weld. Unless you like using a cane instead of eyes.

    3 replies

    Yeah, and 5mA won't COOK your internals.

    No, but about 30mA can ! Under the right conditions and about 10mA can kill livestock.

    To be honest, being a professional industrial electrician, I am amazed at what is going around this place.

    Agenda 21 in full effect I guess ;-)

    Please don't depend on sunglasses to protect you from arcs. The one you generated could be too much for the attenuation of the wavelengths resulting from the arc. Possibly multiple layer filters, such as the semi-rigid film eye shields used by many senior outdoors, but worn over sunglasses would be safer? Also, please don't allow the arcs to be viewed by an audience that does not have adequate protection.

    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:

    4 replies

    Nice schematic. Shouldn't you have a ballast to keep it from over heating though? Although I think the ballast in step 6 of the main post is wired incorrectly. I think it should be in series with the output. No?

    My next step. Only have two for now though. Just have to do a little more searching. In going to start trolling the alleyways around the student housing areas at the local colleges for discarded microwaves.

    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.

    What's the max current/voltage anyone has tried to put into the MOT secondary without a meltdown?

    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

    4 replies

    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

    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?