# [TCML] 1/4 wavelength theory ??

Dex Dexter dexterlabs at dcemail.com
Thu Feb 11 13:23:02 MST 2010

```Thanks for advice.
I think I'll do that with current coil
when I finish my new , bigger coil.
I plan to push then my little coil
to the point of destruction just for a fun.
Will also test your method of getting racing sparks.

looks like normal consequence of the set up described.
Big smooth top loads prevent spark breakout and more
energy gets acumulated,higher voltage built across secondary.
And as you continue to increase coupling the efficiency of energy
transfer increase furtherly resulting in more voltage to.
Some point near the top of secondary gets
finally overstressed and racing sparks start poping out.

Dex

--- Shannon.L.Weinhold at doc.state.or.us wrote:

From: "Weinhold Shannon L" <Shannon.L.Weinhold at doc.state.or.us>
To: "Tesla Coil Mailing List" <tesla at pupman.com>
Subject: RE: [TCML] 1/4 wavelength theory ??
Date: Thu, 11 Feb 2010 11:31:25 -0800

Perhaps we are using two words to describe a similar phenomenon.
There weren't any flashovers between my primary and secondary on my
magnifier.
My secondary coil was composed of insulated wire though, so perhaps that
helped. Plus the primary and secondary were separated by airspace and a
thick plastic insulator that acted as the former for the primary.
Racing sparks, at least by my definition, are long sparks that originate
at some spot on the coil, usually the top, and travel along the surface
of the coil to a lower spot on the coil. If left unchecked for any
period of time it will both burn a significant hole through the
insulation covering the secondary and will destroy the insulation
between individual strands of wire at the destination point and will
leave a carbon track in the insulation along the path traveled while
going from point a to point b. It looks pretty, but its one of those "oh
sh\$t" moments where you franticly reach for the off switch on the
variac...if you're familiar with the consequences.
My experiences have shown that running an oversized toroid/sphere and/or
using an inadequate breakout point tend to stress the insulative coating
on the secondary in the upper section of the windings, and after a short
time this creates a micro-sized hole that streamers occasionally escape
from, and then if the coil is later over coupled the racing sparks will
emanate from these small holes to a lower point on the coil.

So if you want to create it..scratch a little insulation from a small
point on the upper part of your secondary, enough to where the copper is
slightly exposed, then over-couple your coil.
That should do it.

Shannon Weinhold
Coffee Creek Correctional Facility
Behavioral Health Services
Mental Health Infirmary
503.570.6761

"Failures are divided into two classes
those who thought and never did,
and those who did and never thought."
John Charles Salak

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