Bill,
Seems to me the problem you mentioned of the burning secondary
sounds like
the coil was too tightly coupled. If you repaired the secondary
after the burning,
maybe there was still some carbon tracking in the secondary form
which led
to further breakdown. This persistent burning problem is rather
rare and usually
has a very simple solution. There are generally no mysterious
causes for such
an event. I realize you said you played a lot with the secondary
spacing. Maybe
there was some carbon burning in the form. Or maybe even with your
furthest
secondary spacing, it was still too closely coupled.
If the gap is not quenching well, this can cause racing sparks on
the secondary,
but usually they occur all over the secondary, not just at the bottom.
But in any case by copying an existing design, you should avoid
problems as
you suggested.
John
-----Original Message-----
From: Bill Fuller <bfuller@xxxxxxxxxxxxxx>
To: tesla@xxxxxxxxxx <tesla@xxxxxxxxxx>
Sent: Fri, Jul 9, 2010 12:22 pm
Subject: [TCML] New coil modeled after Green Monster
Hello everyone,
It's been a while since I've been coiling and I'm ready to upgrade
my current
coil.
Currently running a 10" coil with 6 to 8 foot sparks.
Looking to up-scale to a 12". I've had some issues with my 10"
burning the
secondary about 3" up from the primary and hope to avoid this on the
12" coil.
Endless playing with primary to secondary spacing didn't tell me
anything. It's
not a primary to secondary arc, it seems to be shorting secondary
turns after
running for a few minutes. Been through 3 secondaries and all had
the same
problem. Flashover perhaps, something geometry related with this
design I think.
That said, I was wondering if anyone can provide me with some core
spec's on the
green monster coil so I can use it as a base model for my next.
David, still
around???
I've looked at the YouTube videos and flickr pictures many times.
This coil
makes long runs with minimum flashover and throws arcs quite a
distance. Nice
work.
Anyway, I have been able to collect some specs (please correct if
wrong);
Secondary: 12.5" x 54", 49" of #19 wire
Topload 12" x 56"
Cap BNZ 2500-104 0.1uF
Primary to secondary spacing 1.5"
Looking for some specifics to avoid flashover and burned secondarys.
Secondary height above primary:
Toroid height above secondary:
For a sanity check on my design it would be nice to know (you may or
may not
have this info...):
Primary and secondary resonant freq.
Coupling factor
Primary and secondary inductance
Thanks in advance!!!
Bill
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