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Re: [TCML] Sudden and unexplained destructive racing spark flashovers
Hi Peter, all,
Yes, the insect scenario is the only feasible explanation
that I have been able to come up with myself, although
I don't think a spider is actually classified as an insect? ;^)
Anyway, I was wondering if a flying insect flew in "too
close" in the general area of the lower end of the second-
ary and caused the inital flashover, which consequently
could have very well led to a cascade, runaway break
down. Since it is summer here on the top side of the
world, the aforementioned ambient temperatures
(probably down to around 90F, or 32C, by the time
these images were shot) would have certainly lended to
the profusion of a multiplicity of flying insects outdoor
during the evening hours. Guess that's the risks one takes
by firing a big coil outdoors. ;^/
As far as some of the other possible explanations such as
humidity or resonant rise in the transmission lines, the main
reason that "I" personally reject these as possible expla-
nations is that: #1. Probably upwards of 80% of all of my
previous firings have been done during similar ambient
temperature and humidity conditions (I don't do cold
weather too well ;^) and #2. I have been using the same
transmissionline setup from just about day one with my
coil setup without any problems before.
Anyway, thank you for all of the helpful input and any-
one else is still welcome to add additional thoughts on
this.
David Rieben
----- Original Message -----
From: "Peter Terren" <pterren@xxxxxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Saturday, June 27, 2009 7:20 PM
Subject: Re: [TCML] Sudden and unexplained destructive racing spark
flashovers
Sounds like a primary to secondary flashover rather than a racing spark.
The primary should never get to 30 kV above RF ground, ie won't spark 1
inch to the coil base although 10 turns up the secondary adds 5kV. The
problem is that a longish wire to RF earth will have a significant drop,
so might develop 10kV across it.
So what was a safe 1.5 inches gap from primary to secondary might have
become say 20kV plus 5kv plus 10kV. which will spark 1.25 inches. Get a
few cosmic rays and occasionally it will jump this distance if all the
voltages align.or if you have a primary strike.
... or it could have just been a spider as I think happened to me once -
hiding in the black cloth I cover the primary with to prevent light spill
from the gap.
Peter www.tesladownunder.com
----- Original Message -----
From: "David Rieben" <drieben@xxxxxxxxxxx>
Hi all,
Quetsion: Can anyone offer a plausible explanation for why an
otherwise perfectly tuned and running SG coil, that we verified
was quenching on the second notch consistantly and first notch
with ground stiking power arcs, will all of the sudden destructively
flash over with secondary/primary racing sparks? I witnessed DC's
Big Bruiser do exactly the same thing at the 2007 Cheesehead
Teslathon and it seems till this day, no one has been able to offer
a plausible explanation for why this happens. I seem to recall DC
citing something about the high humidity causing it but the thing
is, no one else's coil there suffered this same fate operating in
the same ambient atmosphereic conditions as the BB, (including
my Green Monster, at the time) . I sure would like to figure out
what's causing these anomylous flashovers so I can take the
proper future steps to prevent this from re-occuring. ;^/ Anyone?
David Rieben
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