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......
Remove these ads by
Signing UpStep 1Parts List (give or take a few items...)
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)
| « Previous Step | Download PDFView All Steps | Next Step » |
























































So it can transfer electrons to the sphere.
Thanks Dr. Richard Fox
Thanks Dr. Fox
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
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
About distance, everything that was damaged was in close range 5ft or less.
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
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.
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
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
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