Van De Graaff generator and legos.

You have successfully built a working Vandegraaf generator from legos. The basic idea is to use lego pieces to create a high pipe and a motor to rotate two rods, covered with soft rubber/plastic tires, while a belt runs along with them. Two combs made of foil are placed near the rods and tires, with a foil sphere on top. The bottom comb is connected to the ground. To make it work, you need a third roller that constantly rubs against a stationary object to produce electric charge. The right substances for this roller and the rubbing agent are important, with plexiglass and fur being a reliable combination. Insulation is also crucial, and legos may not be the best material for it. However,
  • #1
Vepsu
Umhh.. I'm a pretty newbie on this.. But I'm trying to build a working Vandegraaf generator from legos.
So, the basic idea is that I build high pipe from legos, and then use lego-motor which makes two rods rotate. The second rod is on the top and the second one is on the bottom. They're covered by lego-car-tires (something soft-rubber/plastic) and a belt runs with them as the rods rotate.

Then there is two combs, made by foil, both near the rods and tires. One on thr top and other one on the bottom. Then there is foil sphere on top of that thing. So.. Umhh.. And the bottom comb is connected to the ground.
Could this thing really work? And what I should use as belt? And are the rods (rollers) and combs ok?


Picture of it:
Code:
       _____
      /     \
     |       | Sphere
      \_____/
       | % |
      -|=#=|-    Upper rod/tires
       | # |
       | # |     #=belt
       | # |     %=comb
Motor  | # |
 |__|--|=#=|-    Lower rod/tires, with motor
       | % |
-------------------------
 
Last edited by a moderator:
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  • #2
Hi Vepsu,
I think your design won't work because it doesn't have any parts that can produce electric charge.
Apart from the 2 rollers that hold the belt, you need a 3rd roller which touches the belt from the outside, close to the bottom. This must constantly be charged by rubbing against a stationary object which is grounded.
It is very important to chose the right substances for the 3rd roller and the 'rubbing agent'. You should try many substances until you find a combination which produces static electricity very reliably, even under slightly moist air conditions. My personal favorite is plexi glass (PMMA) plus fur. Always works well when I rub them, but I've never tried them in any motor-driven device. I guess pressure must not be too high but speed must.
The second important point is insulation. I'm not sure if the lego wheels & bearings provide a well-enough insulation, preventing the charge from jumping over. You could test this by building a prototype, and charging up the foil sphere from an external source. See if it holds the charge!
BTW, legos are made of ABS (acrylamide-butadiene-styrol) which is a substance optimized for surface gloss and mechanical strength, but not necessarily for insulation. Maybe legos are after all too hydrophile to provide a good HV insulation. Try it!

There are some websites on how to build your own Van Der Graaff, maybe a google search will help.
 
  • #3
Thanks a lot Arcnets! Maybe this will help me a bit.. :p

I already have other materials beside legos, but I will try with legos first. (They are easy and fun to deal with ;)

I already managed to produce some pathetic sparks with it (I changed some thingies a little..)
I'll try your tips.. I hope it works better.. :)

Edit:

Actually it works now.. :p It produces sparks which travel about 10mm. Pretty pathetic still. Needs some tuning.

I used artificial leather as the belt and the upper roller is alumium foil covered, as the lower is covered with electric tape.
I have to try that fur later..
 
Last edited by a moderator:
  • #4
Working

Now the Van de graaff generator works reliable, though it isn't very powerful, but it charges fast. Maybe the sphere isn't the best possible. It is just a foil covered plastic cup, upper roller is from nylon and lower is from PVC. The belt is made from slices of rubber gloves.

With aid of few Leyden Jars, it produces now over 10 cm (~4 inches) sparks. (For now, I'll try more longer ones later.)
 
  • #5
Congrats, Vepsu!
 

1. What is a Van De Graaff generator?

A Van De Graaff generator is a machine that works by creating static electricity through the friction of two different materials, typically a rubber belt and a metal roller. This static electricity is then transferred to a large metal sphere, creating a high voltage electric potential.

2. How does a Van De Graaff generator work?

A Van De Graaff generator works by using a motor to turn a rubber belt, which rubs against a metal roller. This friction creates a build-up of static electricity on the metal roller, which is then transferred to a large metal sphere through a metal rod or wire. The static electricity on the sphere can then be used for experiments or demonstrations.

3. What are the main components of a Van De Graaff generator?

The main components of a Van De Graaff generator include a motor, a rubber belt, a metal roller, a large metal sphere, and a metal rod or wire. Some generators may also have additional components such as a grounding system or a voltage regulator.

4. Can a Van De Graaff generator be made with legos?

Yes, a Van De Graaff generator can be made with legos. There are several tutorials and instructions available online for building a functional Van De Graaff generator using legos and other simple materials.

5. What are some common experiments or demonstrations that can be done with a Van De Graaff generator?

A Van De Graaff generator can be used for a variety of experiments and demonstrations, such as creating lightning bolts, levitating objects, or creating static electricity to make someone's hair stand up. It can also be used to demonstrate principles of electric charge, potential energy, and voltage.

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