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Re: NASA's Tethered Generator
Subject: Re: NASA's Tethered Generator
Date: Tue, 13 May 1997 01:48:22 -0400 (EDT)
From: richard hull <rhull-at-richmond.infi-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
At 11:54 PM 5/11/97 -0500, you wrote:
>Subject: Re: NASA's Tethered Generator
> Date: Sun, 11 May 1997 22:08:32 +0000
> From: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
> To: Tesla List <tesla-at-pupman-dot-com>
>
>
>At 02:08 PM 5/9/97 +0000, you wrote:
>>Subject: Re: NASA's Tethered Generator
>> Date: Fri, 9 May 1997 02:06:39 -0400 (EDT)
>> From: richard hull <rhull-at-richmond.infi-dot-net>
>> To: Tesla List <tesla-at-pupman-dot-com>
>>
>>
>>At 12:28 AM 5/8/
>>
>>snip
>>>
>>>Hi,
>
>>
>>A wire, even a very short one has lots of capacitance. A long wire can
>>have
>>a tremendous isotropic capacitance. If the wire spans in an electric
>>gradient, Huge potnetials and currents can be obtained against the
>>nearest
>>extended object. The opposite terminal or charge is viewed in theory as
>>being located at infinity, but is most often referenced to the nearest
>>solid
>>object. (on earth it is usually ground) This is actually the modus
>>operandi
>>for the toroid on our Tesla coils!
>>
>> There are other possibilities for voltage rise along such a wire
>>drifting
>>in orbit at orbital velocity. I have alwys commented that a lot of
>>major
>>league electrostatic/electrodynamic research where real large things can
>>be
>>moved about in a rather perfect vacuum could and should be done from the
>>shuttle.
>>
>>Richard Hull, TCBOR
>>
>>-------------------------------------------------------------
>
> Richard -
>
> You have performed many spectacular experiments with Tesla coils and
>discovered some important details of Tesla coil design. I now believe
>you
>should take a wire connected to a meter and move it thru a magnetic
>field.
>You will induce an emf according to the equation
>
> emf = BLv
>
>where emf is the electromagnetic force, B is the magnetic force, L the
>length of wire, and v the velocity of the wire thru the field. This is
>what
>the shuttle tether is doing. The return conductor is the ionosphere.
>
> John Couture
>
>
John,
I am well aware of the above equation, it is part of the original tether
report and mission goal justification data. What kind of mag field
strength
(B) do think is up there? It is still planet earth and a single guass
is
the normal field. This can be boosted a bit with solar storms. The
long
wire will intercept a lot of those fake and imaginary mag field lines
(1/cm). This would indeed militate for a beefy bit of induction assuming
a
good clean closed circuit. There would be much more naked potential
available in the electrostatic end of the business with the large
electric
gradients within the ionosphere over the tether's span.
To provide useable mag induction, the circuit must be a closed one in
the
single turn of wire. This they planned, but never succeeded in doing
with a
large electron gun!!! (in the written report) There can be no mag.
power
induction without that good, solid, electrically conductive, closed
circuit
to yield the usable current in the circuit. Electrostatic potential on
an
isolated capacity is real and requires no classic closed circuit to
develop.
The mag induction circuit, if realized, might supply much more real
usable
power, granted, but no potential, until that key return circuit links to
the
craft (via their proposed electron gun beam.)
I fear the static potential might be a problematic item in any atempt to
use
a tether to take on magnetic induction energy via a long, single
effective turn.
The tether broke mechanically and not electrically, so all is moot. It
seems no one actually knew the dynamics of lowering such a long, heavy,
springy tether into a still extant but thin atmosphere. This was
demonstrated quite well in the abysmal failure of the effort. I have a
report on the matter and a photo of the broken cable. It was a stress
break.
I have discussed this over the last year on and off with two NASA
engineers,
one at Langley and the other at Goddard space flight center, and they
are
amazed the project was ever approved and attempted. Lots of nice
electrical
ideas but no knowledge of the mechanics involved.
Richard Hull, TCBOR