900,000 volt Van de Graaff Generator Using Cheap Parts

Step 18 Diagram

1= dome
2= collector comb
3= top teflon roller
4=upward side of belt positive charge
5-downward side of belt, negative charge
6=bottom nylon roller
7=bottom comb
8=grounded ball
9= SPARK!!!!!!!!!

Comments

[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

[nickademuss]

Its not much as seen by this video,

The potassium chloride is mildly radio active...

And I have worked on the Y-12 reservation in Oak Ridge

[ultraVDG]

Thanks for the video - this geiger counter looks pretty expensive - I noticed you can vary the detection tube to get an incredible detection limit. Back to the VDG´s: Do anyone know about interconnections between the rollers diameter and belt lenght? I am not refering to the belt speed but especially to surface charge densities of the rollers and the belt. Because surface charge density on rollers must high enough to get the combs spray charge. Once I noticed that my belt gets charged pretty good but the dome (faraday cage) didn´t charge up. There was no visible corona at both coms but when I neared my bare hand to the belt I see corona in distances up to 5cm (~2inch). I can´t explain this phenomen and I am pretty sure I connected the bottom comb to ground. It seems that the belt carries the same charge only between (in the middle of) ground and dome?? Sometimes its as bewitches, arghhh, the scientists greatest fear. LOL.

[ineptuslux]

Roller diameter and belt length. If the rollers are too small the belts up side will pass too close to the side coming down and lose a lot of energy to it. Larger diameter rollers are a plus for this reason. The column on the VDG I made years ago is 4" dia. PVC and I noticed the tube glowing when I had it in the yard at night. I looked closer and it was as I said, the two sides of the belt were too close. After making larger rollers (Nylon Top, PVC Bottom) It improved dramatically. The belt is orange vinyl flagging tape joined together by a seal-a-meal heat strip. The sphere is a 12" plastic globe I covered with aluminum tape (not ideal). It is powered by an old 12V 1 Amp portable drill motor and battery with a large pulley on the motor shaft and a small pulley on the PVC Roller shaft with a rubber band belt. The gear ratio is unknown. Real fast is all I can say. It is about 4' from the sphere to the ground. This is where you stop believing me... :-) ... It will produce 1,200,000 Volts (if my math is right and the belt stays on) 4' sparks about every 3 or 4 seconds. They will make your muscles spasm and make a tiny burn on your skin. I have seen 2 to 3' tall plants 4 or 5' away that were glowing in the plasma field. As you approach it the plasma streamers are visible as to where the spark is about to strike. It will light up a 4' 40W fluorescent tube up to about 6' away. It also works a lot better with a glass roller (cigar tube) instead of a nylon one. I am not a scientist so please excuse me if I used the wrong words. I have cannibalized it but the link is a pic of it on FB. The one I'm experimenting with now is a hemisphere on top of a 20' pole with multiple VDGs powering it from the ground. I hope to draw energy from the ionosphere to power my home or at least fry the whole thing with a real bolt of lightning from a cloud. LOL, that would be a good video. Yep, me and Tesla, we be mates. :) Large rollers as far apart on the triboelectric scale as possible, uber high speed and a perfect sphere. (note the carrying handle on the VDG for chasing friends and pets) :-D

https://www.facebook.com/photo.php?fbid=266979466651003&set=a.101237753225176.2999.100000168564168&type=1&theater

[ultraVDG]

hi ineptuslux,

Yes bigger rollers improve the beltspeed and mechanical overall stability.
Take a look on this program http://www.coe.ufrj.br/~acmq/programs/elcal.zip its great to determine the performance of (DIY) van de graaff´s. You only have to double the maximum current calculated from the program because you have current doubeling in your vdg design.
Refering to the programm you can reach a maximum voltage of 450kV for an ideal 12" diameter sphere with an stored energy of 1,7 Joules. If your device reach 1,2MV (possible in pressurised air or sulfur hexafluoride...) it stores 12Joules of energy thats deadly. By the way great idea with multiple vdgs - each of them delivers current that adds to the entire device.

[ineptuslux]

Thank you for the link. I forgot to mention that it was foggy the night I got the huge discharges and the plants around were glowing. I couldn't see more than 30 feet. I assume that had something to do with it since I've never repeated it.

[ultraVDG]

I am sorry: I mean either instead of weather! Can I edit such mistakes? I am new to the community. regards, ultraVDG

[metamedian]

Hi, I'm making a van de graaff generator based on your specifications, thanks! How long does it take to collect enough charge fort he "hair-raising" experiment? Thanks!

[nickademuss]

about 2 seconds