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RE: [TCML] 1/4 wavelength theory ??
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
-----Original Message-----
From: Dex Dexter [mailto:dexterlabs@xxxxxxxxxxx]
Sent: Wednesday, February 10, 2010 1:06 PM
To: Tesla Coil Mailing List
Subject: Re: [TCML] 1/4 wavelength theory ??
Well then,have you ever witnessed flashovers between secondary and
primary (driver) in magnifier configurations at least?
I can tell you that I tried intentionaly to induce racing sparks on my
small secondary by raising coupling and all I could get was flashover
between primary and secondary.
Racing sparks?Hey people,what are you
talking about?Any youtube vid where I
could see the phenomenon?
And it isn't just me.For example,
Steve Conner has built perhaps more then a dozen of various tesla
coils,and never had racing sparks problems ( flashovers he had of
course).
Dex
--- sparktron01@xxxxxxxxx wrote:
From: David Sharpe <sparktron01@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] 1/4 wavelength theory ??
Date: Wed, 10 Feb 2010 13:15:03 -0500
Paul
I suspect the connection you are alluding to is that the "driver
secondary + transmission line" acts as a 1/2 wave transmission line
(current drive <> current drive with some impedance
matching) into the remote resonator that should 1/4 wave length at
system operating frequency. If that is true, an electrical high stress
"node" would (should) appear mid-way up the driver secondary. I've
coupled drivers at tight at 0.6 and never have experienced racing sparks
from mid coil to either end. So maybe my throught process has run into
the ditch (or 2 ft of snow in this neck of the woods... :^D )
On Wed, Feb 10, 2010 at 12:36 PM, Paul Nicholson <tcml88@xxxxxxxxxxx>
wrote:
> Shannon Weinhold wrote:
> > I obviously need to touch up on my tech knowledge before I go
> > spouting off on here. :)
>
> No, please spout! Your question cut straight to the difficulty
> and was a good one. More like that please. Good questions
> are the seeds from which a good thread grows, and a good thread often
> leads to new ideas, and so on.
>
> Fact is, the question of whether a TC is a 1/4 wave resonator often
> comes up, and the answer is both yes and no. That makes it a good
> question - one which a lot of list members would 2nd.
> It creates an opportunity to present a bit of resonator physics,
> which, these days, doesn't get discussed as much as it used to.
>
> Perhaps someone will take the bait in my last post and ask what
> 3/4 wave has got to do with magnifiers.
> --
> Paul Nicholson
> --
> _______________________________________________
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> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
>
--
Dave Sharpe, TCBOR/HEAS
Chesterfield, VA USA
Sharpe's Axiom of Murphy's Law
"Physics trumps opinion!"
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