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Van De Graaff Electrostatic High Voltage Generator

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Step 1: The parts for the VDG

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The only parts in this that you are not likely to find at your local hardware store are the wheels.   I used bed frame wheels. their choice sorta dictated the size of Van De Graaff (Henceforth called VDG for short.)  More about the wheels later.

These are the parts used.
1 Lightbulb socket (I pried out the bottom most contact, to give less surface area to bleed off static charges.
1 Large globe lightbulb
1 1.50"" to 2" pvc adapter (lightbulb socket fits in here nicely, and gives space to mount the brushes)
1 2" to 3" pvc adapter
1 3" to 3" PVC Coupler
1 5" threaded rod and assorted washers and nuts,  I think it was 5/32"
1 6" threaded bolt, and washers, small enough for the wheel to glide on)
2 slightly curved plastic bedframe rollers. (was going to use skateboard wheels sanded down on my drillpress, but my dad had these in his shop)
1 3"x3"x1.50" PVC Tee
1 length of pvc (Ihad to use ABS which is not as good due to its carbon content, but it was all I could find in precut lengths, and didnt want to buy 9 more feet of pipe.
1 1.50" to 0.25" pvc adapter
2 sets of skateboard wheel bearings,
Some copper wire both to make a ground wire, and a spark wand wire, but also to make the brushes.
1 outlet plug (this is only connected to the ground pin
1 can of cold galvanizing spraypaint
1 can of copper metallic spraypaint
1 drill socket adapter. (to turn the bottom wheel)
1 drill, (optional speed controller)
1 sheet of latex exercise banding
1 tube of bike tire patch glue.
Teflon pipe tape,
copper foil tape
Other misc Stuff, A board to screw it down to and some long screws. and A binding post for the charge wand, some wire, a old junk drawer nob pull for the wand, some plastic tubing for the shaft of the wand.

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do you happen to remember what kind of voltage output you got from this design?
killbox
1.How do you make a discharge wand nobody online has a guide on how to make one.
2. I fired up my generator and it worked fine when it didn't go to ground, but when I finally got my ground(the plug in I wasn't getting anything, why is that?
Killbox another question please: My output sphere is 2 salad bowls taped together it stands at about 11 1/2" tall and 9" width in the middle. Also it is an oval shape. Will this still work? And what can I do about the numbers on the bowl?
killbox (author)  newnarutofan1 year ago
sure, the best collector would be a sphere, but you dont need the best possible, should be fine. as for the lumbers, im assuming those are measures? probably dont need to do anything, but if you really want some time with sandpaper or a dremmel with a grinder attachment could probably remove it, but it will probably always show.
thanks hopefully, I will restart construction this weekend. I hope it will work . This project will de termine if I pass or fail the class.
thanks hopefully, I will restart construction this weekend. I hope it will work . This project will de termine if I pass or fail the class.
kill box: 1.does it matter which one of the rollers is on top (like if the copper was on top and the teflon was on bottom)
2. I saw that on my steel bowls there are measuring numbers theres only 3 and I think they are only 1/4" big. Will they effect my charge output. If so how can I fix that (the numbers are dented on the inside and kind of pop out on the oustide if that makes sense)
killbox (author)  newnarutofan1 year ago
1: yes! i think thats the one thing that would matter the most, you want the copper one at the bottom feeding it electrons, and the teflon one above breaking them free and transferring them to the collector.
2: bigger would be better, but mine using the lightbulb was not very huge and it worked. may limit your maximum spark
killbox I have a few concerns:
1. I was thinking about putting nuts on the outside of my top roller to keep it stable. Will this effect the ability to discharge when I have my roller and wire on the inside of the sphere?
2. I also need some tips on creating something my sphere can sit on as support
3.how big does the hole in the sphere have to be?
4. I got some dust on my copper roller. What is a good way to get it clean?
killbox (author)  newnarutofan1 year ago
1: if you can use nylon nuts or small sections of tubing i think that would be best, that way charge wont want to leave the top wheel that way. although if it did i dont think its the end of the world, as the static builds on the axle it will eventually saturate
2: not sure, but if you make your hole in the sphere big enough to just barely go over your pipe at the top (i think you said you were not using a coupler on the top) you could go down atleast to the axle bolt. if you make it tight no mounting would be needed, if its a little loose a few wraps of electrical tape on the pipe would fatten it up.
3: i think i answered that above, alot of the professional vandegraffs just put the support tube up into the sphere.
4:Dunno, maybe a can of compressed air duster? probably wont hurt anything.
Oh ok killbox. Heres what I am thinking about doing:
I bring the wire from a hole in the tee a bit a above the bottom roller. I then pull the wire downwards, then I bend the wire a bit upwards then make an "L" shape at the bottom of the roller where the tips of the of the brush are a bit below the bottom. Will this also work?
killbox (author)  newnarutofan1 year ago
yes, i think so! its just a electron source so pretty much anything that can supply the belt with electrons, should work.
So killbox to get this straight... from the hole on the bottom tee you brought the wire straight down from the hole, then you extended the wire down a bit past the roller , then you bent your bottom brush tips was they were pointing up toward the bottom roller not running parallel (that’s flat) with the bottom roller.
1. DO I HAVE IT RIGHT? 2. Did you do the same thing with the top roller?
3. Also if my wire extends more than ½” will it still work?
4. And how did get your wire to stay put? every time I move just a little bit, the brushes move!
5. I have seen people put there roller and brushes inside of the sphere. I don’t. I thought I would have my roller on the PVC, and brush wire attched to the coupling above the roller, then I have the sphere on the coupling. will it still be work?
6. On a final note would it help if I send you pictures? If so how do I go about doing that?

killbox (author)  newnarutofan1 year ago
Sadly i cant provide pictures, since i have already sold this build at one of our yardsales but i did draw a very crude drawing, (warning im pretty bad with drawing in gimp, and this was a very rush job!) http://www.instructables.com/files/deriv/F1A/UXTI/HEI4FDEL/F1AUXTIHEI4FDEL.MEDIUM.jpg added it to the pictures in the step about the copper wrapped wheel.

#3, sure, you only want it to lightly sweep the belt, but really it can be whatever length will work for you,
#4 maybe you need a little stiffer of wire? not sure without photos of your brushes what may be going on, but once i got mine in place and fanned out and trimmed flat they were really no trouble.
#5 yes the roller and the brushes inside would work a little better, less loss less bleedoff and such, but i was surprised to see how well it could work. using the socket and lightbulb (which would be impossible)
killbox I have a couple more questions about the brushes
1. When I do my bottom brush I drilled a hole a bit above the roller, had it coming straight down on the inside of the pipe, holding it together with a plastic loop, when I get to where I want the brush I bend the wire up and snake it to the roller. Will this still work?
2. I got it when you said the brushes go with the direction of the roller when it’s rolling, but I am a bit confused about the tips of the brushes. Do they go along the wheel (basically flat) where the tips are a bit after the wheel, or are they before the roller, or in the middle of the roller? Or do they point upward towards the roller?
killbox (author)  newnarutofan1 year ago
mine poked into the side kinda even with the roller, but there is like a 1/2" clearence there so then they were bent upward in about a 45 degree angle to just barely have the tips touching the belt probably 1/2" above the roller, on the side where the belt would be going in an upward dirrection.
Oh I forgot to add one more thing, my pipe in 16in long (giggity, giggity, goo) and i am cutting(2) 2 1/2 in slits for the top roller. is this to tall?
killbox (author)  newnarutofan1 year ago
I dont know if there is much of a maximum/minimum distance. My gut instinct is it will scale fine. ive seen 1' tall ones and 4' tall ones. although the on in the instructable was my first and sofar only one ive made.
Thank killbox.
1. I have heard people wrap electrical tape around there rollers to make a barrel shape then they put a thin layer of their copper or Teflon around it. Does this actually work?
2. And was thinking about putting the screw below the roller, wrapping it up and try and get the brushes to glide on would this also work?
3. I put my dome together by bonding the lids with epoxy and wrapped 4 layers of electrical tape on the outside, the rims are still on the bowls. Will this work?
4. And I put 1 layer of electrical tape on the bottom where I cut a hole to reduce the corona charge (I think it’s called this). Do I need more layers?
killbox (author)  newnarutofan1 year ago
1, I dont know, mine were already barrell shaped, i cant see why it would not work.
2, i think as long as your pretty much on or near the roller you will be fine.
3, the lips of the bowls may cause some discharge but no i suspect you will be fine.
5, static is a bit of a different creature than most electricity we are useto. a single layer of electrical tape can stop sparks from flying in the 1-800v range, but as voltage goes up it does need to be thicker, i can only say try it out, and then maybe try it with more to see if you see any difference. it will probably be fine.
I have another few questions (2 about the bottom roller, and 1 about the top roller)
1. Where does the screw go on the tee?
2. How did you get your bottom roller to get straight and perfectly centered? When I tried to do it the belt pulled up on the roller. I also tried to get a piece of thread rod to go all the way to the other side on the bottom roller. Do you have any ideas on how to get it straight?
3. How did you get your notches so square and centered and leveled on the coupling? I am using the coupling for something else. I tried to get the notches on the PVC but it didn’t work out hints?
killbox (author)  newnarutofan1 year ago
1, it was on the side of the wheel just a bit above it. in the photo of the tee with the wheel with copper tape, you can see i drilled the hole for the wire, as i recall the wire poked in went around a screw then with the brush facing kinda upwards along the side of the belt.

2, im guessing i was lucky when i pressed in the bearings, and put the fitting in everything was tight and level and my threaded rod i had already tested to see if it was straight by rolling it across a desk. im thinking if the fittings are loose at all (like the plug with the bearings in it, you might be able to use a some tape or some paper to make it fit more snugly.
3, i just handsawed them down, to a measured mark, and then broke them out. i thought they were level, but in the end i had to stick a teeny shim in the bottom of one to keep my belt centered
Killbox I finally have my belt on.
1. the top part of it is centered but the bottom part keep moving toward the right edge but it still is on the roller but barely, will this still work or does it need to be perfectly centered?.
2. I have also heard that the rollers material does not have to be thick. Some people said only a thin outer jacket of the copper and Teflon and have a thick layer of electrical tape underneath of that makes the bumps. Will this still work?
3. Where did you get the copper tape and what is the brand name?
4. And I noticed that copper is rubbing from the lower wheel to the belt is showing up on the belt. Will this short is out? If so how do I if it?
5. And I am still having trouble with the bottom wires. I can’t seem to get them to the right width with out them getting sucked in.
killbox (author)  newnarutofan1 year ago
1, 5, sounds like your bottom roller may not be staying level. not sure what to say about that. perhaps wedging some thing like paper in the fitting might keep it tight and straight. your belt may be a little short and cauing too much tension,

2, i don't think it needs to be thick, not sure about the rubbing off, hopefuly not enough to become conductive along much of the belt, mine didnt rub off that i ever noticed.
killbox (author)  killbox1 year ago
oops, hit enter too soon.

3, copper tape i had for a long time, i think it came from an electronics supply shop(used for rf shielding and grounding), may also be able to get it from art supply places. (its used in stainglass work)

5, not sure what you mean by sucked in, they should brush along the belt, the same direction as the belt goes, so if they are getting moved you might be going against the belt direction?
thaks again killbox. I have another question. The brushes, do they kind brush over the wheel glideing over the wheel or are the to the side completeley. I have also twisted the wire going to the sphere one wire and duct taped it so the bare cooper is touching the sphere. Will this still give me the zap I need?
killbox (author)  newnarutofan1 year ago
I dont know if it really matters, as long as they are near the wheels, mine were right on them, probably best since along the belt it can wiggle more and not scrape the electrons as well.
killbox (author)  newnarutofan1 year ago
should be just fine,
Which do the brushes face. and is it ok for the tip of the bristles go over the center of the whell?
killbox (author)  newnarutofan1 year ago
the brushes should go the same direction you choose to make the belt go (when you decide which way the drill makes the belt go) mark the direction somewhere. so if the belt is going around clockwise, you want the bottom brush to be following along on the belt on the bottom pointing left and the top pointing down to the right. or the opposite if you have it going counter clockwise, you can imagine if you got it wrong the belt will grab and bend your brushes, otherwise they will just kinda gently sweep on or off the electrons from the belt.
hey kill box my belt keeps slipping off. I know its not the bed rollers. please help
I think I my have solved the problem. I just put more tephlon tape in the middle of the top roller and let the bottom one be is this ok?
thanks killbox I have finally started consturction and the hardest part for me is the belt I am using a medium (blue color) yoga exercise band. I have also made my brushes they do not all the way across but I thinks I will still work? And I have another question 1. For my top brush have twisted 3 wires together and fanned them out and for the sphere I have twisted them and mage them 1 wire as it were, will this still work?
How can you be sure the brushes are touching?
killbox (author)  newnarutofan1 year ago
the top one is pretty easy, just make sure its lined up with the wheel and angled so its rubbing. for the bottom one its a little more tricky especially once the band is on, but i found with a flashlight i could look down and see it. i had it coming in touching the side of the bottom wheel, id say make your brushes a little extra long to be sure.
the links that you gave me are either dead or i can't access them
killbox (author)  newnarutofan1 year ago
odd i can still pull up both photo links they are jsut images off of google image search. try cutting and pasting them into the address bar of a new browser window/tab
Dude killbox you are like a godsend to me. I have one more question I swear. If i did get a drill with a cord on it how do you construct the inductive dimmer box (i think I am saying it right), I have no idea. Please tell me in stupid steps (thats the only mode I work in)
killbox (author)  newnarutofan1 year ago
Really no big deal, keep asking questiions you need to ask. Im good with them, its one of the reasons i helped startup a Hackerspace here.

As for the dimmer box, im going to give you this image i just found off of google, just imagine that you put the 2 wires going to the light bulb to an outlet, i would also run a line up to the ground. here is a diagram for a dimmer, and followed by a diagram for an outlet, http://businesslocalarticles.com/wp-content/uploads/2012/08/wiring-diagram.jpg

and

http://www.buildmyowncabin.com/electrical/wiring-gfci-outlet.gif

I would suggest a cheap rotory dimmer switch, and there is no need for a FGCI type outlet pictured in the diagram, just cheap hardware store dimmer and outlet., mounted up in a double gang outlet box also available from the hardware store.

And for a cord, i just used a spare computer power cord, with the computer end cut off.
Thanks killbox by the way I have few more questions.
1.Is it ok to hold the wire going to the globe (i am using 2 salad bowls epoxed together with duct tape on bottom hole and to help hold the 2 bowls together) with duct tape on the inside, and when they say connect to the spere does that mean the entire wire is bare or just the top and is it frayed, also is does it matter how high you put the wire.
2. I am have a hard time getting the belt to stay in place any suggestions?
3. Also is the wire to bottom rollor, the wand, and the plug to ground interconnected (on the same screw)?
4. And finally is using a single piece of stranded wire ok for the top and bottom brush ok. And if not, I am having a hard time make the brushes with three any suggestions?
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