120000 Volt Van de Graaff Generator

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120,000 Volt Van De Graaff Generator by Tool Using Animal on March 24, 2007

Table of Contents 120,000 Volt Van De Graaff Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Intro: 120,000 Volt Van De Graaff Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Step 1: Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

Step 2: Making the sphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Step 3: The motive system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Step 4: The Belt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Step 5: The Base and column . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4

Step 6: Gross assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

Step 7: The brushes and tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6

Step 8: What's the voltage Kenneth? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Related Instructables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

http://www.instructables.com/id/120%2c000-Volt-Van-De-Graaff-Generator/

Author:Tool Using Animal I'm a graduate of the University of Central Florida with a degree in Mechanical Engineering, I am currently working on my Master's. Otherwise, I enjoy building things, designing the things I'm going to build, and fishing.

Intro: 120,000 Volt Van De Graaff Generator It's Frankenstein time. Who doesn't enjoy the smell of ozone and the snap of a big fat spark?

The dome is rotating due to vibration Although a Van De Graff generator has recently been posted I decided to post mine based on it's substantial differences.


Step 1: Supplies We'll need Two matching mixing bowls electrical tape 3" PVC pipe closet flange 1/2" pvc pipe and end caps a bucket superglue assorted nuts and bolts A 540 size electric motor copper wire for brushes and a pair of pantyhose ;-)

Step 2: Making the sphere Start with your mixing bowls, BIGGER is BETTER. Measure how tall one bowl is and write that down somewhere I wrote it inside the bowl. Cut a 3.25" dia. hole in the bottom of one bowl, a sheet metal nibbler makes this easy. Now tape the two bowls together with electrical tape, and then tape around the nibbled opening. We use electrical tape not because it's insulating, it's not at these voltages, but because it smooths and reduces corona discharge.

Image Notes 1. tape 2. tape

Step 3: The motive system The motive system consists of a roller made of pvc pipe attached to a 540 size motor. To build the roller carefully drill a hole smaller than the motor shaft diameter through the center of each end cap. Heat the motor shaft with a lighter and press one end cap onto the motor shaft squarely. Now cut a short length of pipe and assemble the roller. The bearing for the end opposite the motor is made from a piece of hardened steel rod epoxied to the head of a bolt. The top roller is made similarly to the bottom roller only it rides on simple brass bolts and is covered in aluminum tape.


Step 4: The Belt This is where you need the pantyhose. Cut the legs off at the crotch and cut the toes off the legs. We'll use the legs for our belt, depending on the height of our generator you;ll make adjustments to total belt length, It should be stretched but not taut, or taut but not tight ;-). Anyways, overlap the ends of the leg and hold it in place with some scotch tape and wick in some superglue, hit it with some accelerator or let it cure overnight. If you use accelerator wash with alcohol after to remove residue.

Image Notes 1. Glued, the bottle was used as the superglue wouldn't stick to it.

Step 5: The Base and column The base is an old laundry bucket , inverted. Lay the power roller and motor on top of the bucket and mark the location of the mounting holes and roller location. Using those markings locate the closet flange and mark it's mounting holes and the area inside to be cut out. Cut out the hole to match the closet flange and drill out all the locations for assembly bolts. The column is easy, simply mark down one end a distance equal to the height of one mixing bowl, now mark four points equidistant around the pipe at that location. Drill a 2" hole through the pipe through two opposite points and a pair of 1/8" holes through the other two points.

Image Notes 1. motor stand offs may be necessary 2. laying out the location

Image Notes 1. flange mount 2. end cap axle 3. our neighbor to the north 4. motor mount


Image Notes 1. top axle hole 2. access hole

Step 6: Gross assembly The column is mounted to the bucket with the closet flange. The power roller is mounted inside the bucket and the mounting manipulated to make roller perpendicular to the column. The belt is slipped on BEFORE adjusting the roller. The belt is then pulled through the column with a scrap of wire and the top roller installed using small bolts threaded into the PVC with nuts on the inside, as axles. At this point apply a few volts to the motor and check to see the belt runs true, if it runs to one end, the end of that roller needs to be moved OUT, where out is away from the middle of the machine.

Image Notes 1. aluminum coated roller 2. brush

Image Notes 1. brush belt and roller Discovered that covering the roller in electrical tape gave a slight improvement to the spark


Image Notes 1. motor roller support

Step 7: The brushes and tuning The brushes are multi strand copper wire fanned out and mounted approx. 1/4" inch from the belt roller combo at each end. The top brush is connected to the inside of the sphere and the bottom brush is connected to ground, whether an earth ground or power supply ground seems to be irrelevant. At this point slip the dome on and apply about 6 volts to the motor. You should feel a charge around the dome. Tuning. Don't allow the brushes to rub against the belt, the deposited copper will make the belt conductive and the generator will stop working. If it fails to work at all adjust the brushes and try again. If all else fails degrease the rollers and belt with rubbing alcohol, grease is death to triboelectric charge separation.

Image Notes 1. connects the brush inside to the dome's inside

Step 8: What's the voltage Kenneth? The breakdown voltage for dry air at sea level is commonly given as 3 million volts/meter. So for every centimeter of spark you have 30,000 volts. So far my longest recorded spark is 40mm or 120,000 volts.


Image Notes 1. graphite coated ping pong ball.

Related Instructables

Build an Electrostatic Motor by John Chase

The World's Simplest Electrostatic Machine by innovationview

How to Make a Table-Top Van de Graaff Generator by DevCoder

Mini Van De Graaf... M & M style! by mcraghead

Be a Scientist: Build an Electrostatic Motor by Kiteman

Van de Graaff Generator made from junk by Sedgewick17

Comments 50 comments Add Comment

view all 175 comments

peacefoots says:

Feb 5, 2011. 1:20 PM REPLY

how small of a motor can you use

mujeebmurtaza95 says:

Mar 10, 2009. 12:30 AM REPLY

will this make your hair stand on the end or not....please tell, i need it 4 a science project!!

ixonstater says:

Jan 22, 2011. 4:00 PM REPLY

yes, it will

sam971221 says:

Dec 18, 2010. 5:03 PM REPLY

Thanx. Sooooo useful.

generator 2 says:

Jun 16, 2010. 7:07 AM REPLY

cool !

smithy.exe says: it all depends on the length of your legs and the height of your generator


May 14, 2010. 8:32 AM REPLY

goodcoldwater says:

Mar 29, 2010. 9:50 PM REPLY I noticed corona discharges at the center edges of the dome on the video above. Corona points are electrical charge dissipations that decrease a VDG’s potential output. To reduce this phenomenon you should smooth out and round off any acute edges and or angles. The more round and seamless the dome is, higher the output. Just a tip!

sheial360 says:

Jan 25, 2010. 11:03 AM REPLY

I have followed all the instructions but my generator still does not work ...everything runs but there is no spark . do you have any ideas of maybe why it does not work??????? or what i can do to make it work ?????

goodcoldwater says:

Mar 29, 2010. 9:34 PM REPLY

To sheial360 : Make sure that the Bottom brush side has a good earth ground connection. If you’re using a 120V motor to turn the roller look for the Green wire on the motor power cord (make sure you unplug the motor first) it’s usually located in the electrical termination enclosure or motor housing and connected to a terminal post. This wire is used as a fail safe wire just incase the motor were to short, but it also serves as a good grounding point which runs to the earth ground for your house. Use a fork or ring connector with the right Gauge aka “AWG” size to make the connection, and be sure to crimp the connector properly. I wouldn’t recommend grounding to another spot on the frame, due to higher resistance, unless the frame is made of copper or silver, which is highly unlikely. OR you can stake a 5 to 6 piece of copper pipe or rod into the ground, leaving about 6 inches sticking out to tie in your ground ( if you do this make sure you use a copper ground clamp when connecting your wire.) Also you need to consider Humidity, it’s harder to produce sparks in humid atmospheres. Running your VDG indoors with the AC on might help. Also instead of using panty hose, try using a surgical rubber tourniquet or tube for the band ( Split the tube down the middle with a razor evenly) sand the ends down to a taper apply rubber cement to the ends, overlap them and press together. Lay the glued ends on a flat surface and lay a heavy book or heavy flat object on the glued ends to help seal them together (make sure you wipe away any excess beforehand to keep the band from sticking to the other surfaces) and just wait until the bonding process is complete. I hope this helps you!

sheial360 says:

Jan 18, 2010. 11:47 AM REPLY

So does the bowl have be cut so the PVC pipe fits in it and the bowl covers the hole that was made and the roller ?????? , And does the sock have to move or does it stay still ????

Tool Using Animal says:

Jan 18, 2010. 1:06 PM REPLY

Yes the bowl must be cut, the roller absolutely must be inside the domw. The sock must also move, just like a fan belt on a car

instructa-fan says:

Nov 18, 2007. 12:11 AM REPLY ADVICE TO ALL VDG ATTEMPT-ING-ERS; I know that the only things i got stuck on in my four non-working vdg's is the rollers. As simple as, two different materials such as plastic to metal,(used here) and the ground. Now the ground is only needed if you are using a hand crank. you can just do what he also does here, and ram it in your electrical outlet, this will be a bottom brush. hope this helps!!! (just made my good one today, AWESOME!!!!!!)

Kryptonite says:

Dec 11, 2008. 5:16 PM REPLY Whoah whoah whoah whoah whoah, NEVER EVER stick anything into the ground of your electrical outlet!!!! Let me make this clear, you will probably get a very nasty jolt of mains supply electricity, with chances of it killing you. No joke, do not attempt this!!!!!!!!!!!

Xellers says:

Jan 19, 2009. 4:26 PM REPLY Why? I use an old computer power supply that has been hollowed out for ground all the time. I took out all of the circuits, and then cut the mains lines and glued all over them to keep them insulated. Now, I just plug it into the wall, and the only connection left is the ground one to the metal case. Works like a charm for crystal radios, Tesla coils, and such.

Kryptonite says:

Jan 28, 2009. 2:00 AM REPLY It depends on how much experience you've had. I take it back, when I said "never ever stick anything into the ground of your electricity outlet" I was thinking of your average beginner hobbyist. You can do it, I agree, but getting a plain wire and sticking it in isn't a real good idea. I stick with an outside water tap, just in case. Thanks for your point of view anyway!

Xellers says:

Jan 28, 2009. 5:14 AM REPLY The real reason why you shouldn't stick anything in your ground outlet is that it doesn't work well. You need an RF ground like a big metal pole (2-4 ft.) in the ground.

ogorir says:

Jan 7, 2010. 5:17 PM REPLY by code(at least in michigan) your house ground needs to be attached to a 6' copper pole stuck in the ground, i believe, so it is below the frost line. Presuming you've insulated the other wires coming from the plug properly and presuming your house wiring is correct and to code* you should be fine using the ground pin in your outlet. * use an outlet tester. always. every time. before you plug anything over 1000W(commercially produced) or home-made into an outlet. most wiring is shoddy, incorrect, or just not safe. better to be safe than sorry.


Kryptonite says:

Jan 29, 2009. 2:29 PM REPLY Hmmm, alright, just I've seen numerous warnings on kits and stuff that you need a ground, I know an electrician who warned me about it and my dad's built a house and warned me about it... Coincidence?

Betelgeus3 says:

Sep 26, 2010. 9:07 AM REPLY There's really nothing dangerous about sticking anything in a ground, only if you're connected to a hot lead would that hurt you. No power is transfered in a ground unless something goes wrong.

Kryptonite says:

Oct 10, 2010. 1:19 AM REPLY

...and knowing the number of times that happens! :P But thanks for telling me.

static says:

Dec 22, 2008. 2:30 AM REPLY In the event the ground terminals in your receptacles have anything, but a 0(zero) potential, there is a problem with the wiring.

krissy551 says:

Dec 19, 2009. 6:15 AM REPLY

who is going to make this he/she said that it was 120,000 VOLT!!!!!!!!!!!

Jodex says:

Dec 25, 2009. 1:00 PM REPLY You're not going to die if you'd touch it. It doesn't have much amperes. Amperes are the ones that kills you. Did you know that when you're petting your cat there's over 15 000 volts, but next to no amperes, just couple of micro amperes.

emeraldamber says:

Sep 30, 2009. 8:15 PM REPLY I really don't get the bottom brush connected to the ground... is it connected literally just to the ground..? and what is it for...? me and my groupmates are trying to make one... we used Teflon for the bottom roller and aluminum at the top but it would just not work. does the motor have to be fast working? what should be the mixing bowl made of? aluminum? stainless? help! :(


Sep 30, 2009. 8:32 PM REPLY The bottom bruh really is just connected to ground, it's just a soucre of charge. the mixing bowls can be any metal, on mistake I've seen over and over again is the top roller and brush MUST be INSIDE the mixing bowls. The faster the motor the faster the charge builds up and it is a race against how fast the charge leaks away. Pix are always a help in diagnstics.

cupofsoup says:

Sep 30, 2009. 1:36 PM REPLY

very cool thanks

emeraldamber says:

Sep 20, 2009. 10:21 AM REPLY hi, so batteries are the main source of power for this one? can't it make hair on head stand? what should be done to make hair on head stand? :D how much did this all cost?


Sep 20, 2009. 1:17 PM REPLY Cost? it came from my junk box, so I don't know. TO small and leaky to make hair stand on end, increase size, minimize corona leakage. Batteries spin the motor, and yes, technically they do the work of chage separation, Tesla published a wonderful article on the subject in Scientific American in the '30's.

josephsushil says:

Sep 15, 2009. 9:30 AM REPLY

will our hair stand up with this van de graff

vijayanandrckz says:

Aug 4, 2009. 11:02 PM REPLY

where r de van de graff generators used in practically

vijayanandrckz says:

Aug 4, 2009. 11:00 PM REPLY

what r the limitations of these van de graff generators

slipknot rules says: Van de graafs work best in under 40% humidity :)


Jul 3, 2009. 2:04 AM REPLY

DrdNaught says:

Jul 2, 2009. 9:48 PM REPLY

y dont you just stitch it 2gether??

Leonyferreira52 says:

May 18, 2009. 4:40 PM REPLY We already made the generator but id like to know if i can plug an A540 motor to 110 volt outlet. or do i have to buy a converter 110 volts to 6 or 9 volts. please respond ASAP, thank you leony


May 18, 2009. 5:36 PM REPLY

NO NO NO NO!!!!!!! You must use DC, because of the surrent draw, I wouldn't suggest using a wall wart either.

rk1776 says:

May 6, 2009. 1:34 PM REPLY ours is in progress. We are using a drill instead of an RC motor. It is more powerful but slower so we are going to use a band made from rubber so that we create more friction. Will update with more details soon.

rk1776 says:

May 12, 2009. 11:21 AM REPLY the drill isnt fast enough to generate enough friction so we changed from a nylon belt to a rubber belt made from a bike tire innertube. testing today will update soon.

snowman62494 says:

Apr 14, 2009. 6:10 PM REPLY

will this make your hair stand on end

nguyenalexandert says:

Mar 16, 2009. 6:27 PM REPLY I just got mine working, however the sparks are really weak... i have to get within a few centimeters for it to give off a little spark, and it's not even 100% of the time


Mar 16, 2009. 7:18 PM REPLY Sorry man, been busy with school, The bottom roller is slipping because it's Teflon, a low friction material, try wrapping some electrical tape around it temporarily to see how that works. Electrical tape has a much high coefficient of friction, the belt should slip less, Or perhaps tighten the belt some.


Mar 16, 2009. 8:13 PM REPLY Thanks no problem, anyways i was able to make the belt work, I actually made a new belt with only one leg. By stretching it out as much as possible and making it really tight. The leg did not stretch as i left it in there for a couple hours. However i ended up taking off the teflon because i wasn't sure if it was helping. I also got some sparks working after i attached some aluminum foil to the top roller, however it's really small... gatta get within 1 or 2 centimeters of the bowl before any sparks happen. Any suggestions?


Mar 16, 2009. 8:27 PM REPLY a video wouldn't hurt. One thing is total spark size is limited by dome size (but I don't remember the parameters), also, you could try operaring it in a perfectly dark room, it would need to be completely dark, and see if you can se any blue corona coming from any locations that would need to be insulated.


Mar 16, 2009. 9:47 PM REPLY I posted up 3 vids, the first one is my van der graph without the dome, as you can see the rollers are spinning pretty quickly, my belt is moving quickly but it's squished up in that corner, and... that's about it. The second video actually has something in it ;) if you look closely towards the end you'll see some blue, that's the sparks their's barely anything almost not even noticeable. Also the 3rd video is pretty much just to prove that it's working in a way, the tissue paper is rising, and as i get the thing to shock me the tissue goes down


Mar 17, 2009. 9:32 PM REPLY

I couldn't quite tell, is the top roller below the dome, or inside the dome?


Mar 17, 2009. 10:36 PM REPLY The dome is placed on top of the black pvc, the top roller is inside the black pvc towards the top, it's beneath the dome, the brush howeeever is attached inside the bottom of the dome. i think my problem might be that the belt squishes up in the corner? but it is pantyhose... so i can't really stop it, can't make it lie out flat


Mar 18, 2009. 8:10 AM REPLY The belt problem is caused by a slight misalignment in the rollers, if you can't adjust the roller you can try building up lightly the side it is running to with tape, for the top roller you can buy aluminium tape at the hardware store, in the HVAC section. The dome position, this is the real problem, the physics of van de graaff generators means that the top roller and brush assembly absolutely MUST be located within the dome. Allow me to explain, as I'm sure you know like charges repel, if the belt and brush are inside the dome the charge is transferred to the dome and migrates by repulsion to the outside of the dome, this leaves the inside uncharged but since the belt keeps moving new charge into the dome it keeps migrating to the outside, and theoretically the charge on the outside could rise to infinity! Practically it won't but you get the idea. When the brush and roller are outside the dome, the charge can only rise to the level of the charge on the belt, which is very small.


Try this real quick experiment, disassemble your dome and just invert one of the bowls over the top, make sure the brush is atached and as long as the lip of the bowl is lower than the roller I'll bet it works much better.


Mar 16, 2009. 10:10 PM REPLY

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Mar 16, 2009. 10:11 PM REPLY


Mar 14, 2009. 10:25 PM REPLY I just built mine 3 days ago, and need some help with the belt. I got it running it's just that it's not moving that quickly. The bottom roller has teflon on it, and the top has aluminum. I tried it without teflon, and aluminum also. For some reason not catching on? The bottom roller is moving pretty quickly though. Could you help me out? i could post a video of it

mujeebmurtaza95 says:

Mar 10, 2009. 7:28 AM REPLY how many volts is a 540 motor .. i hav a 9volts motor will it wrk/???nd wat happens if we touch the top(the orb kinda thing) with our bare hands??? will our hair stnd up or sumthng?

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120000 Volt Van de Graaff Generator

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