re: Racing arc clues...

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

Original poster: "Charles Hobson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <charles.a.hobson-at-btinternet-dot-com>

You posted:
----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, May 30, 2001 8:12 PM
Subject: Racing arc clues...


> Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
>
> Hi All,
>
> We are working on racing arcs on the TSSP project.  Here is an interesting
> point during the secondary ring up for a k=0.12 and k=0.20 situation:
>
> http://hot-streamer-dot-com/temp/Vgrad.jpg
>
> The differences are sort of subtle but many clues are being noted.
>
> I was wondering if having the secondary "clean" as opposed to being dusty
> or dirty made racing arcs worse?  I am thinking that dirt would make
> ionization do to rapid voltage changes more likely.
>
> I also know that "over coupling" and "mistuning" are factors.  Are there
> any other consistent things that have an bearing on this?
>
> Where do racing arcs tend to occur most?  I have often heard near the base
> of the coil but I think they sometimes appear near the top.  It 3rd
> harmonics are a factor, that may make some sense.
>
> Still many unknowns but looking for more clues...
>
> Cheers,
>
> Terry
Hello Terry,

I had very bright racing arcs which ran down along my 3" x 14" secondary
coil starting at mid point to about 2" from the bottom secondary turn. From
there it jumped to the top end of my 8" diameter 1/4" copper tubing helical
wound primary coil. The primary is tapped from the top down for tuning. I
coiled a two inch wide strip of 5 mil polyethylene sheet (left over from
pre-MMC days) in the way we use to coil up notebook paper for pea shooters,
and slipped it over the end of the copper tubing. (about 6 layers) The
racing completely stopped.

Other data: Primary cap. 15nF, Powered by 8.4kV 35mA NST  System frequency
305kHz. k =0.18 determined by measuring two peak frequencies around the
resonant freq. and then doing the  standard calculation. Reasonably
confident all tuning was proper.

Other observations: Before the polyethythene fix, racing occurred with and
without break out points on the terminal. Tried different system loadings
after the fix such as with and without break out points, grounding rod close
and at maximum solid spark length. No racing occurred.

Chuck          .