Where's Van De Graff On This Board?

[TinselKoala]

Ha!

That's pretty good. A LEGO VDG. I wonder if the LEGO includes instructions for the machine.

But actually I know how to make an even simpler one. Just take a little dc motor, make a loop of silk thread, and dangle a small yo-yo shaped bit of metal from the loop, suspended from the motor shaft, over the edge of the table. Turn on the motor, so the "yo-yo" is spinning, hanging from the loop. Now you should be able to draw off a tiny little spark from the yo-yo.

[TinselKoala]

I made this demo a few minutes ago, showing electrostatic oil jet ejection, which illustrates the power of the E-field to accelerate objects along the gradient. If anyone can give me advice as to how to make a better video of this phenomenon, I would be glad to hear it--lighting, background, etc.
http://www.youtube.com/watch?v=rxy4mPHIWFM

[TinselKoala]

I put a bigger capacity on the top of the positive machine, and here is a video of it making some sparks.
http://www.youtube.com/watch?v=OLeRgo2dQn0

[the_big_m_in_ok]

Clara Listensprechen said:

Where can I find on this board any discussion of Van De Graff? 

You can't.  This is the only thread; I checked.
But in order to make a Van De Graff generator work, there's a usually mechanical(read: motorized) means of generating static electricity in there somewhere.  That could take enough power from any other storage means to eliminate any OU.
There's always the Water Wheel, though.  Fill an airtight container with butane that's connected on the other side of an axle to an empty one, same size.  Immerse the butane-containinig one in hot water until the butane boils and then condenses in the opposite empty one.  Several on the axle will turn the axle by the off-centered weight and gravity's settling of the unbalance.  Efficiency is at least 90%, by one estimate 30 years ago in Popular Mechanics magazine.  Increase the wheel speed by a step-up set of gears and use that to power the Van De Graff motor.

Anybody else besides me think that the Van De Graff and the 2N3055 oughta get married?

50,000-100,000 VDC? would need to be stepped down to about 12 V to keep most transistors from frying.  Or wire several hundred in series to allow for more current-carrying capacity---if needed.

Van De Graff's are okay for collecting a charge using a capacitor.
Maybe the lightning power plant could be combined with the Van De Graff?
Lots of current in lightning, though.

--Lee

[onthecuttingedge2005]

why not use a Carbon mesh belt on a Van De Graaf, the Carbon Mesh has more surface area to carry a greater charge. it should give it a higher density of charge delivery to the top load.

for instance, you can use several layers of Carbon mesh to form a thicker belt for even better charge density.

I think it would be even better than a pelletron if the belt was made right.

Jerry