[Prev][Next][Index][Thread]
Re: Toroid Design .
Tesla List wrote:
>
> Original Poster: Ed Phillips <evp-at-pacbell-dot-net>
>
> "Ed -
>
> Isn't the charge zero on the inside of the upper terminal during VDG
> operation? How can there be an "up hill" effect for the charge on the
> belt?
> I would consider it a "down hill" effect.
>
> The work to put the charge (100% eff) on the outside of the terminal
> is
>
> W = Q x V joules per coulomb
>
> Have you found an equation to relate this work to the motor that would
> indicate the motor slows down as the voltage on the outside of the
> terminal
> increases?
>
> John Couture"
>
> Yep, the charge on the INSIDE of the upper terminal IS zero, but the
> VOLTAGE on the outside isn't!!! Here is an analogy which at least hints
> at what is happening. As the belt moves "up" (toward the upper
> terminal) you are moving LIKE charges to it; since like charges repel,
> it takes work to move them "up", and that work is stored as additional
> charge on the upper terminal. As the voltage on the terminal increases,
> the "hill" is getting higher and the repulsion is getting greater, hence
> the greater load on the motor. By the way, I built a small hand-cranked
> VDG once, and it was possible to see the belt "back away" from a
> highly-charged upper terminal when the crank was released.
>
> My eyes are on the blink at the moment, so don't feel like
sitting down
> at the desk and figuring, but shouldn't be much work to figure out the
> actual work being done. Will give it a try when I'm doing better.
>
> Ed
Note added 12/31/98:
For a really neat animated illustration of charge transfer in a VDG
look at:
http://www.pelletron-dot-com/charging.htm
Ed