900,000 volt Van de Graaff Generator Using Cheap Parts

Lets build a 900,000+ volt Van de Graaff generator!!

I built this one in about a week, using scrap parts from a sewing machine and materials ordered from http://www.grainger.com/Grainger/wwg/start.shtml

I have seen the larger machines in operation at my local science museum and this one does just as well. I have made hair stand on end and even pie pans float up and off the machine.

For an explanation of operation go to Wikipedia:

http://en.wikipedia.org/wiki/Van_de_Graaff_generator

ALSO, note that this machine can generate enough static to stop a pacemaker and any other digital device, keep people with heart problems away. Also if you dont wont to blow up you sensitive electronic devices make sure you either use the machine on a separate circuit or unplug everything you want to keep. I have also stopped watches and killed cell phones with it. The current is low around 27micro amps but that's a thousand times whats needed to kill say your flat screen TV or pc/laptop.

Well if your know anything about Van de Graaffs you know that the bigger and smoother the sphere or collector the bigger the charge. Any bump or lip on the sphere and all the charge will run to it and bleed off.

You see the voltage is determined by how much you can store on the surface of the dome, sphere, collector. I used a 12" stainless steel garden gazing ball. I bought it from a garden supply center for $40.00. it throws faint sparks around 12" and strong bright ones at 8" to a grounded door knob. That's 883,920 volts by the calculator or 4350 volts per millimeter.

The recharge rate or time it takes to build up a charge high enough to jump from the sphere is determined by belt speed and width.

I used an art program to generate some diagrams and several pics of the completed unit, its a simple mechanism and you could upscale it for a larger machine easily topping 1,000,000 volts. all you need to do it increase the sphere size and belt width.

This one is an upscale version that I used to test equipment at work and I used the little one to determine the best belt material.
I tried plastic tape, rubber, fabrics, and the hands down best was a plastic coated fabric used in hotel shower curtains. Its easy to cut and glue and lasts for a long time. The charge it carries was easily 50% better than everything I tried.

Also to get the most of your machine you will need to get your hands on some Teflon and some nylon to make the rollers out of. I ordered mine from Granger (links in parts list) I used the Teflon for the top and nylon for the bottom or drive roller. You can also get the Teflon from stacking little half inch thick disks cut with a 2" diameter hole saw from cutting boards. You could also make the top and bottom roller out of the same material and coat the top roller with Teflon tape.

Also if you want to boost your storage and spark a bit build this:
Leyden jar of DOOM!

I will try to list as many tips threw this process as I can. Its been several years since I built the machine and its worked well so far.

Enjoy,
Zachary M.
Clinton, TN

Next up a parts list......

Step 1 Parts List (give or take a few items...)

Sphere-- Garden gazing ball, stainless (glass or plastic will not work)
4" PVC sewer pipe 24" long
4" PVC sewer pipe coupling
2" Diameter 2.75" long Teflon roller Grainger Item # 2NJA2 http://www.grainger.com/Grainger/items/2NJA2
2" Diameter 2.75" long Nylon roller Grainger Item # 1UTY5 http://www.grainger.com
12" x 12" plywood 3/4" thick
12" x 18" plywood 3/4" thick
1/2" all thread (threaded rod) you will need enough to make four pieces 9" long.
1/2" nuts for the all thread, you will need 16 of them also 16 washers
4/40 by 1" bolts I used about 10 of them
Power switch, 120v 5amp
Sheet of copper, I got mine at the hobby store 9 or copper roof flashing at a hardware store.
box of stick pins
3/4 inch copper pipe around 14" long (I would get at least two feet so you have leverage to bend it)
120volt power cord
120volt sewing machine motor with drive pulley and belt. (mine was from a Brother) Or Usehttp://www.grainger.com/Grainger/items/2M033 and Small pulley Granger PN 1X459
12" x 12" PVC sheet 1/4" thick (thick plexi glass will work just as well, and look cool to!)
Axel for top and bottom rollers (whatever you can find, I pulled mine from the sewing machine)
120v panel light, optional
PVC glue
Super Glue medium thickness for the belt
Vinyl covered fabric for belt (shower curtain or cheap strap)

Comments

[paperjack]

I don't understand, does the copper tail have to touch the sides of the sphere or it has to stay in the middle of the sphere without touching anything?

[nickademuss]

IT touches the sphere as close to the top center as possible.
So it can transfer electrons to the sphere.

[paperjack]

Can the sphere be far away from the comb? As in, not covering it.

[nickademuss]

It can but wont develop much of a charge.

[homeopathicfox]

Hi, I am Richard Fox and I appreciate all you have presented. I decided to make a bigger version of this and I am only getting a 1 inch spark. I have done something really wrong. I used an 8 inch green water pipe and 6 inch rollers It waould be great to talk to you in person. could you email me your telephone No. or could you call me at 510 590-1033. I would appreciate it. I think in a few minutes you could tell me your answer.

Thanks Dr. Richard Fox

[nickademuss]

Richard, send pics of your set up to my email [e-mail]

[homeopathicfox]

Hi, I forgot to add my email address. It is [e-mail]

Thanks Dr. Fox

[art.z]

Hi, very nice instructable.
I've been wanting to make a VDG myself but I have some questions:

What gives greater voltage and current?
The size of the gazing ball?
The materials of the rollers and belt?
Or the speed of the belt?

Plus, how do I measure the current and the voltage after it's done?


Thank You

[ultraVDG]

1. The size of the gazing ball is proportional to the achievable voltage - bigger ball leads to higher voltage.

2. The material combination of the rollers and the belt determine how many charge per area is on your vdg´s belt for transportation. But remember there is a limit (~ 26µC/m²). You can get around this limit (higher air pressure, SF6 instead of air, ...) but it´s difficult for "hobby scientists".

3. The speed of the belt is proportional to the current - more speed more current.

4. Because of corona loss you need enough current to get the ideal reachable voltage.

Measurement:
short circuit current: get an analog instrument (http://www.elv-downloads.de/bilder/artikel/Produkte/9/949/94971/Internet//normalneu/94971_w01_messmodul.jpg) you need 0-50µA or 0-100µA.
A digital meter will usually be destroyed without proper precaution.

voltage: spark lenght gives a rough estimate - there are tables. A calibrated field mill will do the job (http://en.wikipedia.org/wiki/Field_mill). An electric charge meter (http://www.elektor.com/magazines/2003/november/electric-charge-meter.55404.lynkx) can also be abused to determine voltages.

hope i can help,
ultravdg

[nickademuss]

couldnt of said it better myself :)

[mmboyajian]

I couldn't find any copper roof flashing. Can I use Aluminum roof flashing?

[nickademuss]

try your hobby store for copper sheet, aluminum would work but is very hard to solder to...

[stpierre473]

We are thinking about using a bigger motor one used for farm equipment with an adjustable dial. with two industrial mixing bowls welded together and and ground down on the edges then buffed. do you think that should give us more spark?

[nickademuss]

the motor should be fine, the important part is that you get the largest sphere without edges of any kind, it may be easier to get a garden gazing ball.

[seansippo]

do i want the bottom comb touching, or like the top one where it is close as possible without touching the belt?

[nickademuss]

as close as possible to the belt without touching

[checker5]

out of curriosity were did you get the Nylon and Teflon rollers

[nickademuss]

cole parmer for the nylon and teflon

[nickademuss]

also granger has it.... you can also use nylon bed rollers...

[bungalowdan]

To Author: I joined instructables to build your VDG. THANKS FOR THE PLANS. I plan to upsize to a larger ball and wider belt. One question: I don't want to fry any of my computers or other electronics. Since the charge is electrostatic, is the main concern the proximity of the VDG to electronic devices? Did you ever fry anything besides your computer speakers?

[nickademuss]

yes having the VDG close to anything digital is a risk, I know they try to make devices withstand a static charge but if you can feel your hairs moving near it, the charge will overcome the devices protection, to date it has shut down a wired network, killed a cellphone, stopped a watch and reset a hub....

About distance, everything that was damaged was in close range 5ft or less.

[coolpizzadude]

what did you use for a roller

[motoflair]

what did you use for the belt? the rollers can be made from junk car cars.

[snoggle1]

Ha motoflair, what are car cars...?

I am going to try a intertube for my little 250 kv and see how good or bad it works. Unless someone already tried. zap zap

[rubylaser163]

car intertubes have carbon mixed in them to harden the rubber and will not work ..carbon conduct electricity....use big rubber bands if u can find one big for ur machine but make shure its pure rubber...george

[nickademuss]

I added links to the parts page

[ysbearing]

Slewing bearing called slewing ring bearings, is a comprehensive load to bear a large bearing, can bear large axial, radial load and overturning moment. http://www.1stbearing.com

[christian2gothic]

everytime i look up "how to" for these Van De Graaff projects there seems to be a lack of details on the brush where the static is passed from the belt to the metal. please include more information on what you did here and why, as i find it a bit confusing. how do you avoid damage to the belt while having a metal rub against it the entire time it's in motion. i would think the metal would scratch up and quickly destroy the belt. what do other people tend to use for a metal brush?

[nickademuss]

go to step 11, it shows where the comb or brush is mounted...

[ultraVDG]

hi christian2gothic,

brush=comb
The brush doesn´t touch the belt. The charge (you call it "static") is transfered trough the air onto the belt because of breakdown field strength (of air) is reached with sharp edges form the brush.

[makincoolstuff]

does the comb touch the belt

[wii552]

no

[kwingart]

So I have a somewhat ignorant question. Is it possible to use a ground not connected to you house? Perhaps a common ground? I am think of building a lower powered "handheld version" but all the models I have seen have used the safety ground from the house electrical system as ground. Any input would be appreciated.

[wii552]

You can do that, and, in fact, your body would would be not that bad as a ground. Add a thing that you hold on to that connects to the bottom brush

[ultraVDG]

Hi nickademuss,

great work, thank you for sharing!
I have a question about the rollers:
If you are using nylon as the lower roller and PTFE (Teflon) as the upper one you should get a negative sphere charge (belt is vinyl (PVC) coated)? Weather my triboelectric series (http://de.wikipedia.org/wiki/Reibungselektrizit%C3%A4t) are wrong or you are experimenting with a negative voltage above 100kV. Thats problematic because you eventually collecting radioactive particles on your sphere (most radioactive particles positive due to valence shell electron loss).
sorry for my bad English!

ultraVDG

[$20Scientist]

I think you're right. A positive bottom roller like nylon would attract a negative charge onto the belt which would be repelled by a negative top roller like teflon onto the sphere. This should make the charge on the sphere negative. Please tell me why I'm wrong nickademuss.

[nickademuss]

Thanks! So I could use it to collect radon in my basement? Its most defiantly a positive charge on the sphere, the charge is attracted to negative surfaces. and dont worry about the English, its fine.

[ultraVDG]

Hi nickademuss,

you can collect the decay products from 222Rn (see http://de.wikipedia.org/wiki/Uran-Radium-Reihe).
Our physics teacher has set up a wire on insulators with -6kv.
After one day he take a handkerchief an wash the 1,5m long wire. He get a blackish residue in the handkerchief, which let a geiger-counter "gone wild".
Be careful with this radioactive dust if you perform this experiment.

regards,
ultraVDG

[nickademuss]

Very interesting! Im very familiar with radiation as I live less than 5 miles from Oak Ridge, TN. I may have to dust off my old Geiger counter and see if anything is warm. What were the actual rads of the experimental above? You can make a Geiger counter go crazy with "no salt" the salt substitute.

[ultraVDG]

What for a salt substitute do you mean? I hope its not for human/animal use.
Unfortunately our teacher only demonstrats the crackling sound of the collected dust in comparison to the "Nullrate=zero rate?" with the counter.
Today I found a german internet site (http://j-grzesina.de/radioakt/umwelt.htm#philion) which says that a charged plate (~ -20kV) after 5 min exposure to radon containing air shows a decay rate of 493 counts per minute without zero rate (529 cpm with zero rate).
I am interested why you are so familiar with radiation and what´s the interconnection to Oak Ridge (are you working at the National Laboratory ?)
I am familiar with radiation because the tschernobyl desaster. I can remember, when I was a child, my father don´t let me play in the garden as my grandfather was lown mowing x days after tschernobyl. Today I live in Weingarten near Ravensburg, here our physik teacher told us that he had measured extrem high radiation levels when it was raining a few days/weeks after tschernobyl that is around 1500km away, but I can´t remember an exact reading. Today the value is around 0,1-0,2 µS/h.
My laptop had some problems with the connection to this site yesterday.
So my Reply was not send to the server, argh.

regards,
ultraVDG