Re: Gap Question

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

Original poster: robert & june heidlebaugh <rheidlebaugh-at-desertgate-dot-com> 

Bart: You are correct the current and voltage is Not constant. A charged
capacitor delivers max voltage and current then decays at a rate of 63%/time
constant. In a arc the resistance and the Time is changing so the current
dose not follow the pure discharge decay of a simple RC time constant curve,
but for explanation a simple explanation is better than a complex snow job
with all ihe varriables included.  One step at a time.
--     In 1958 we built a plasma jet to test its usefulness as a thrust
source. A plasma jet is basicly a water cooled arc. we used a gas powered
generator as a power source. We ran the generator at max rpm then started
the arc with a 20 Kv spark. the current started to load the generator as
current went to 50 amps then we added water to produce a plasma. The current
went to over 400 amps and the generator nearly stalled producing tempratures
simulating the surface of the sun. The resistance approched that of a copper
rod. The same action is found in any high current arc, But not so extream as
a plasma jet. As  a plasma is formed the plasma gas resistance drops to a
few ohms and decreases resistance until the plasma flame begins to loose
power and size like blowing a balloon and releacing the top. The balloon
start small gets large and then deflates, Resistance is the reciprical of
the plasma size. Bigger plasma cloud less resistance, less power less cloud.
      Robert   H


 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > Date: Wed, 25 Feb 2004 21:24:55 -0700
 > To: tesla-at-pupman-dot-com
 > Subject: Re: Gap Question
 > Resent-From: tesla-at-pupman-dot-com
 > Resent-Date: Wed, 25 Feb 2004 21:47:18 -0700
 >
 > Original poster: Bart Anderson <classi6-at-classictesla-dot-com>
 >
 > Hi Luke, All,
 >
 > This has been a good discussion!
 >
 > Tesla list wrote:
 >
 >> Original poster: "Luke" <Bluu-at-cox-dot-net>
 >> Sorry, when I wrote gap in this post I should have said arc.
 >> So when the term negative resistance is used what is meant is that the
 >> resistance value is changing in a negative direction (getting less)?
 >> Is that a correct statement?
 >
 > That's how I'm coming to visualize from what the others have posted here.
 >
 > Here is what I'm seeing: The voltage is very high and when an arc path is
 > forced. The large potential pushes a large current across the path and
 > takes the path of least resistance. In the case of a high current arc, the
 > path of least resistance isn't a single initial arc path. It takes less
 > energy to force the surrounding air around the initial arc path to become
 > conductive than it is to wait for the current to cross this small pathway.
 > Thus, the resistive portion around the initial arc path is forced into
 > conduction. The area of conduction increases and the resistive region
 > decreases. There is a maximum at which the VI product can force the
 > surrounding resistive gas into conduction. Once this maximum is reached,
 > because the voltage is decreasing, the resistive portion begins increasing
 > as the area of conduction decreases.
 >
 > I have a question for the list.
 >
 > I can't visualize the current remaining constant and is what I thought I
 > read in one of the posts (maybe that was just for conceptualizing the
 > process?). As the conductive area changes throughout the process, the
 > current should also change concentrically with the resistance as the
 > voltage drops. If the current is constant, I don't understand how. A larger
 > number of pathways should increase the current value at any point in time.
 >
 > Thanks,
 > Bart
 >
 >
 >
 >