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):

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.

Comments

[gobitz]

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!

[houdini0118]

concrete is actualy a conductor a poor one but it dose conduct it is used in alot of higher wattage resistors

[modog4000]

how do you build a ballast

[HVahead]

http://www.instructables.com/id/Home-made-ballast/

[HVahead]

nvrmnd thatnot an actual instructable...

[muttyfutty]

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]

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)

[muttyfutty]

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]

you can, keep in mind that a MOT usually uses 1500W of power, the light bulb would be decimated.

[muttyfutty]

I've got an 150W halogen bulb. will that work or do I need a larger value? what do you reccommend?

[DevCoder]

i still recommend another MOT, just go dumpster diving a little

[muttyfutty]

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]

LOL! You should make some pasta with it :D

[muttyfutty]

yep, pasta and high voltage, a pretty good combo (what about the sauce?)

[LuciferTengu]

use the arc to "euthanize" a crab or two and make a bisque

[muttyfutty]

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..

[croslandjr123]

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.

[bryanb333]

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]

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]

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

[Jimmy Proton]

ewh, metal smoke! don't breath this!

[Plasmana]

Haha! "Will it blend? That is the question" I love his shows

[Jimmy Proton]

hahahaha me to

[jbyrns1993]

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]

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.

[Highjump44]

 can u explain the stick 
 and wat two contacts is the spark jumping from

[tristantech]

The stick is used so the author can touch the wires together with out burning or electrocuting himself.

[Highjump44]

 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

[Musicman41]

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.

[alah]

Please excuse if I´m wrong, but I thik you made a mistake in your schematic. If you want a series configuration to double the voltage output, both secondary HV outputs should be IN SERIES: i.e. X2-1 should not be grounded. Your schematic shows both HV outputs IN PARALLEL. That gives the same output voltage, but doubles the output current.

[Electronics111]

If you connect between the HV out on each transformer you get ~4kv. Between each HV out and the grounds of the HV out you get ~2kv.

[rik3098]

i never new aplug could be grounded whats it grounded from tv,computer,wii???LOL

[rik3098]

dude that could blind you

[eric m]

why use 2 transformers?

[DevCoder]

There are 2 reasons for that. The second transformer can be used as a ballast for the other, and you can also run both the transformers in parallel to give off 4 kV. Seems as though I need to update my Instructable :)

[Wesley666]

If it is in parallel then you are just doubling the current. If they are in series you double voltage.

[eric m]

Can you get an arc with one mot ? I have some mots for building a welder but i touched the secondaries to everything and don't get any kind of arc like you do. Got them from a repair shop. They're probably burnt out.

[DevCoder]

Yeah, you can just wire up one of the transformers and get about a 4 cm arc (2cm per kV).

[recon506]

Wait, isn't the resistance of air 10,000 volts per cm? Or am I mixing something up? (Based on a Mythbusters episode, btw) -recon506

[TheDeviant13]

that is initial arcing distance but once an arc forms it can be pulled farther because the air ionizes and becomes less resistive I made a carbon arc lamp with an older flourescent tube ballast and it practicaly had to touch to start the arc but it could be pulled to about half an inch after about 3 seconds