Introduction: 120,000 Volt Van De Graaff Generator

Picture of 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

Picture of 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.

Step 3: The Motive System

Picture of 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

Picture of 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.




Step 5: The Base and Column

Picture of 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.

Step 6: Gross Assembly

Picture of 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.

Step 7: The Brushes and Tuning

Picture of 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.

Step 8: What's the Voltage Kenneth?

Picture of 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.

Comments

my wookie (author)2013-02-15

would a bike tire inner-tube work instead of panty hose? not the easiest thing to get your hands on when your a guy.

JakeV (author)my wookie2015-09-28

What, you mean stores will discriminate against you and refuse to let you purchase panty-hose? Or are you afraid of the hypothetical stares and double-takes?

my wookie (author)JakeV2015-09-28

: ) inner tubes dont work very well

devansh gupta (author)2015-05-13

will it make my hair stand?

newnarutofan (author)2013-03-27

does anyone know how to make a discharge wand. I am confused.

Vineetm95 (author)2012-05-27

Hey Where to Connect this Wire Help...

https://www.instructables.com/files/deriv/FEO/12V4/H2MYLY7L/FEO12V4H2MYLY7L.MEDIUM.jpg

nilved (author)2012-03-26

Im using a rubber belt as the belt must the brushes touch

nilved (author)2012-03-23

do the bowls have to be aluminium ?

nilved (author)2012-03-22

I am making a van de Graaff for my school project and I am using a site that you will find at http://mark.rehorst.com/Van_de_Graaff/index.html plz can you tell me if you have to use your hand to make a spark or can you use the pole type thing used in this instructable to make the spark? if so how and where do I connect it ? please answer quick ,its urgent thx

sbhatia2 (author)2011-11-28

wot is d rate of rpm of d motor.?

pareshmotiwala (author)2011-05-29

do the rollers move

They spin.

can somebody please help?

hcarmona (author)2011-05-22

how well does it work compared to the teflon and nylon rollers?

peacefoots (author)2011-02-05

how small of a motor can you use

mujeebmurtaza95 (author)2009-03-10

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

yes, it will

sam9712 (author)2010-12-18

Thanx.
Sooooo useful.

instructa-fan (author)2007-11-18

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 (author)instructa-fan2008-12-11

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 (author)Kryptonite2009-01-19

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 (author)Xellers2009-01-28

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 (author)Kryptonite2009-01-28

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.

Kryptonite (author)Xellers2009-01-29

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 (author)Kryptonite2010-09-26

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 (author)Betelgeus32010-10-10

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

ogorir (author)Xellers2010-01-07

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.

static (author)Kryptonite2008-12-22

In the event the ground terminals in your receptacles have anything, but a 0(zero) potential, there is a problem with the wiring.

generator 2 (author)2010-06-16

cool !

smithy.exe (author)2010-05-14

it all depends on the length of your legs and the height of your generator 

goodcoldwater (author)2010-03-29

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 (author)2010-01-25

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 (author)sheial3602010-03-29

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 (author)2010-01-18

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 ????

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

krissy551 (author)2009-12-19

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

Jodex (author)krissy5512009-12-25

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 (author)2009-09-30

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! :(

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 (author)2009-09-30

very cool thanks

emeraldamber (author)2009-09-20

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?

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 (author)2009-09-15

will our hair stand up with this van de graff

vijayanandrckz (author)2009-08-04

where r de van de graff generators used in practically

vijayanandrckz (author)2009-08-04

what r the limitations of these van de graff generators

slipknot rules (author)2009-07-03

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

DrdNaught (author)2009-07-02

y dont you just stitch it 2gether??

Leonyferreira52 (author)2009-05-18

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

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

rk1776 (author)2009-05-06

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.

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