Re: Ion Motors

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <twftesla-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

Tesla list wrote:
> 
> Original poster: "Christopher Boden" <chrisboden-at-hotmail-dot-com>

> What is the largest dia an Ion Motor can be made to function?

No limit if you can generate enough current at high voltage to power it.

> What is the largest ever built?

I have seen one with about 1 meter of diameter.
 
> Can an Ion Motor be made to spin vertically?

Yes. You can even couple small wheels to it, one at each side, and make 
it climb a pair of inclinated rails.
 
> Can an Ion Motor be made from a disk with pointed projections sticking 3"
> out from the side at right angles to the radious (if they were straight in
> it would only spark and not turn)

Can. It would have a lot of inertia in this case, and get speed more
slowly.
 
> Is this the same principle that makes our Lightning Pendulum work?

No.
 
> Lightning Pendulum.
> 
> Hang a 4"dia hollow sphere of some metal (we have used stainless (float
> switch) and bronze (fake cannon ball) with success) 3' from a support over
> an insulated table. Have the ball hang about 1" up from the table.
> 
> Place a metal plate on the table, centered under the ball.
> 
> To hang the ball, use thin wire, 22AWG works fine. Insulate the hanging
> point.
> 
> Place 2 pop cans about 12" apart on the table, on axis from the ball.
> 
> Connect the wire that the ball hangs from to one side of an NST. The other
> side of the NST connects to the metal baseplate.
> 
> Swing the ball, plug it in, and be prepared to make half an hour of tiny
> adjustments as to the exact position of the cans.
> 
> If, at the end of each swing, the metal ball arcs to one of the cans, it
> will swing as long as power is applied to the NST.
> 
> Thoughts?

With AC input and the cans grounded, this is not the usual electrostatic
pendulum. But I see what can be the origin of the force that pushes the
balls. There is electrostatic attraction between the ball and a can 
when they are approximating. At some distance, an arc appears, and as
the
voltage at the ball drops to a low value, the force decreases, appearing
again only when the arc disappears. But the ball moving away from the
can stretches the arc, as in a Jacobīs ladder. The arc then starts with
a certain distance when the ball is approaching a can, and ends only
when
the distance is higher, when the ball is moving away from the can.
So, the electrostatic force pushing the ball against the can only
appears 
later, and with smaller intensity. The overall effect is that there is
a force that pushes the ball against the cans, but only a weaker force
that tries to hold it when it moves away from them.
The heat from the arc can also help in pushing the ball away from the 
cans, heating the air and producing a small pressure.

Interesting experiment. I will see if I can reproduce it.

Antonio Carlos M. de Queiroz