RE: [TCML] Poly thickness (does matter!)

["" <dr.hankenstein@xxxxxxxxxxxxx>]

Gary,

I do agree that the sparks in the "after" photo appear quite a bit smaller
than the "before" photo. You have to remember that there was a four month
laps in time between the two pictures. We kept looking at the first photo
to try to determine exactly where the camera was and tried our best to
place it accordingly. If you examine the "after" photo carefully, you will
notice that the coil appears quite a bit smaller than in the first,
indicating the camera was either further away, or the zoom was a little
differently set. The sparks are the same length except they tended to want
to be more on the right in the "after" photo for some reason. Also, for
your information, the variac was at 20 ~ 25%.......this is another
variable, and: I racked the variac up to full power for 2 secs during the
last ten secs of the exposure in both instances for effect. I do not
believe that this had any bearing on the "racing sparks" that we actually
did not even witness during either film take. The racing sparks were
invisible to the human eye! The camera added a "bonus" if you will to the
overall experiment. The main objective was to see what the difference would
be by adding substantially more insulation to the original secondary
winding. The results are clear....longer sparks, no racing sparks at any
available power level on this coil configuration. Hope that clears anything
up as far as what, where, why and how we pursued this adventure. I would be
interested in other ideas / comments for future implementation.

Regards,

Woo      


> [Original Message]
> From: Lau, Gary <Gary.Lau@xxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Date: 7/14/2008 7:01:19 AM
> Subject: RE: [TCML] Poly thickness (does matter!)
>
> Hi Woo,
>
> I reviewed your experimental write-up at
http://www.audiotesla.org/corona%20experiment.htm
>
> The thing that strikes me is that in the before and after photos under
"The Results", the spark length in the After photo appears to be
significantly shorter than in the Before photo.  The Before photo shows the
corona skirt and racing sparks, and this would all be consistent with
either less power being applied, or reduced couping in the After photo. 
This makes me less than certain that conditions were actually identical. 
But I can fully appreciate the difficulty in duplicating conditions over
such a long interval.
>
> While strong evidence might persuade me to think that some coating types
might affect the tendency to develop racing sparks, it's a stretch to
suggest that spark length might be significantly affected.  It's my
understanding that the E-field surrounding the secondary and top-load is
governed by the geometry of conductors, not insulators.
>
> The photographs you took are an excellent diagnostic tool.  It's a shame
that most common digital cameras can't achieve the equivalent film speed of
ISO 1600 without being overwhelmed by noise.  Your images clearly show that
the toroid is too far from the top of the secondary to adequately shield it
and prevent the corona skirt that begins at the top of the secondary.  I
would wager that if you added a very small toroid just above the secondary,
it would eliminate the skirt, and permit a higher coupling before racing
sparks occur.
>
> Regards, Gary Lau
> MA, USA
>
>
> > -----Original Message-----
> > From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> > Behalf Of dr.hankenstein@xxxxxxxxxxxxx
> > Sent: Saturday, July 12, 2008 6:14 PM
> > To: Tesla Coil Mailing List
> > Subject: [TCML] Poly thickness (does matter!)
> >
> > Gary,
> >
> > I beg to differ with you on this point. I used to think the same thing
until we did a
> > recent experiment: I refinished an old secondary, one I had been using
for 14 years
> > and was astonished what 20+ coats of fresh polyurethane did for the
coils
> > performance. Noted was the elimination of a "corona skirt" under the
gradient ring
> > (top load). The occasional racing sparks have been eliminated not to
mention I now
> > have the closest coulpling possible with this coil. I used to use a 1"
spacer under
> > the secondary to decouple the coil. Spark length has increased 4 to 6"
as well. For
> > more details, please check out the article I wrote on this experiment
at:
> > http://www.audiotesla.org/corona%20experiment.htm
> >
> > Regards,
> >
> > Woo
> >
> >
> > > [Original Message]
> > > From: Lau, Gary <Gary.Lau@xxxxxx>
> > > To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> > > Date: 7/1/2008 10:01:59 AM
> > > Subject: RE: [TCML] Poly thickness
> > >
> > > I'm not convinced that coating a secondary with anything
significantly improves it
> > electrically.  Mostly it's to keep the windings from shifting on the
form, and to
> > provide a small amount of armor should something bump into it.  And
probably
> > most importantly, it just makes the coil look nice and shiny.  No
matter what one
> > coats the secondary with, it's still vulnerable to racing sparks if it
is overcoupled.
> > >
> > > Regards, Gary Lau
> > > MA, USA
>
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