Re: secondary question...

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "David Rieben" <drieben@xxxxxxxxxxxxxxx>

Hi,

The good Dr. brings out a good point here. The first (and
only) secondary coil internal flashover that I have ever ex-
perienced was some 20 years ago with my first "working"
coil. I had given up on building one from "scratch" and
broke down and purchased the Info Unlimited "BTC1"
Tesla coil kit. it had a 4" diameter gray PVC pipe
secondary coil form wound with what looked like #24
or #26 magnet wire and was powered by a 6 kV, 23
mA OBIT and a .005 uFd cap. The secondary coil form
length was around 16" to 18", IIRC. It had a topload
that appeared to be a small, upturned aluminum funnel
with a hollow brass? ball brazed to the bottom (top as
mounted) of the downspout. Once properly tuned, it
could still only do about 8" to 10" streamers. Then one
day (before the OBIT bit the dust) the output streamers
suddenly went down to almost nothing. I couldn't figure
out what had happened at first but a removal of the
"funnel" topload revealed a nice, jagged carbon-path
running the entire length of the internal wall ;^( Remember
though, that the secondary coil length was still longer than
the 10" max output sparks. I've since built a few coils that
actually produce sparks considerably longer than the se-
condary coil form with not internal baffles and haven't
experienced any internal tracking. Since learning about in-
ternal baffles, I have installed them in all of my coils since
then (last 8 to 10 years). My Green Monster, pole pig
powered coil does have 3 (I believe) internal baffles, al-
though neither of the baffles really make an airtight seal
to the internal walls by any means. The secondary coil is 12.5" x 49.5" long
with a 12x56 topload and I can easily
get very bright 12 ft+ arcs from this beast with no internal
secondary tracking to date.
http://www.teslauniverse.com/members/drieben/

David Rieben

----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Monday, October 09, 2006 9:11 AM
Subject: Re: secondary question...


> Original poster: "resonance" <resonance@xxxxxxxxxxxx>
>
> It's not the dia. of the coil that determines whether or not a baffle
> is necessary.  It's the spark length as compared to the length of the
> coil. Anytime a spark length approaches or exceeds coil length a
> baffle should be employed.  It's easy and time efficient as compared
> to hours of sanding, resealing, and perhaps rewinding a secondary
> that has flashed over internally.
>
> Dr. Resonance
> ----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
> To: <tesla@xxxxxxxxxx>
> Sent: Sunday, October 08, 2006 11:28 PM
> Subject: RE: secondary question...
>
>
> >Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>
> >
> >Hi,
> >
> >Interesting Idea. Anyone know if the foam stuff is polyethylene? Little
loss
> >in that case. You could just put end caps on it. Do 4" coils even need a
> >central baffle?
> >
> >Jim Mora
> >
> >-----Original Message-----
> >From: Tesla list [mailto:tesla@xxxxxxxxxx]
> >Sent: Sunday, October 08, 2006 7:11 PM
> >To: tesla@xxxxxxxxxx
> >Subject: secondary question...
> >
> >Original poster: Slurp812 <slurp812@xxxxxxxxx>
> >
> >OK, so I got some PVC, and been doing research on secondarys. It was
> >sugested somwhere that baffles be installed on the inside. OK, so I
> >was thinking of a quick and dirty way of sealing up the inside. What
> >if I were to just fill the inside of the secondary PVC pipe with
> >expanding foam? Do you think that would work, or make it more lossy?
> >
>
>
>