Re: 60" Discharge spark with Resitor.

To: tesla-at-pupman-dot-com
Subject: Re: 60" Discharge spark with Resitor.
From: FutureT-at-aol-dot-com (by way of Terry Fritz <terryf-at-verinet-dot-com>)
Date: Mon, 07 Sep 1998 09:19:20 -0600
Approved: terryf-at-verinet-dot-com
In a message dated 98-09-06 13:43:07 EDT, you write:

<< Something very strange happened while running the coil with the 430 ohms
> resistor.  I had a spark come off of the 6" sphere like it was trying to
> strike a target across the room 12' away.  The spark held its shape and hung
> in the air for about 30 seconds.  The spark started out about 24" long and
> grew in length about an 1" longer per second. It was about 60" long for
> several seconds.  I usually get lots of sparks off of the sphere all at the
> same time but when the extra long sparks was forming all other sparks
> reduced in length and quantity. It was like the extra long spark was pulling
> power from all the other sparks. The 60" spark never struck a target.  It
> just held its shape and hung there making a frying sound.  One long
> continious purple spark.  The spark never moved or changed its shape.  It
> was like the spark was following a conductive path in the air.  Suddenly the
> 60" long spark disappeared and about 10 to 12 branching sparks appeared all
> around the 6" copper sphere.
 
> Gary Weaver
  >>

Gary,

This is an interesting test you did.  I didn't think a 6" sphere could
push out 60" sparks at that power level, so we learn every day, don't we?
My guess is that the higher resistance, allowed the spark gap to quench
better, but I'm surprised 430 ohms made much difference.  It must have
been on the *edge* of quenchability.

Regarding the slow growing 60" spark, I've experienced something
similar at very low break-rates of 60 breaks per second, although the
effect was not so pronounced in my case.  I had posted about it in
an old posting named "quenching and surging" or something similar.
Basically I think the gap was on the edge of quenchability, and as the
spark grew, it loaded the system and helped the quenching, which in
turn improved the quench.  So it was a positive feedback system of
improving quenching, up until the point when the spark hit a ground,
then the gap brightened considerably (poor quench), and the process
began anew.  Average sparks were maybe 30", but grew occasionally
to 45" in a somewhat slow manner, but didn't take a full minute to
grow, but only about 10 seconds or so.  I was using a sync rotary gap
however.  It was interesting that as the spark lengthened, the gaps
dimmed (due to better quenching), so there was a direct but inverse
relationship between spark length and gap brightness

It is possible that your system benefited from a chance occurance
of air currents and ionization conditions that favored the creation of
the long spark at that moment.  You are correct, when one spark forms,
it tends to utilize the power that would have gone into the other sparks.

Did you notice if your gap dimmed as the streamer grew in length?

John Freau