[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[TCML] G. Monster's updated ARSG - was: Poly thickness
Hi Bart,
Oooook, that's a little bit clearer :^) Not
that I have a complete and full grasp of it
but I can at least somewhat see what you're
talking about now ;^) It's basically the surface
of the coil itself that's acting like a capacitor
(just like the topload's surface area acts as one
plate of a cap and the surface of nearby objects
the other) and not the space between each adja-
cent turn.
Anyway, while it's fresh on my mind, I just ran
the Green Monster tonight with the aluminum
shaft collars around each flying electrode. I
love July 4th in America as that's the best ex-
cuse in the world to fire off a huge coil and not
have to worry too much about p***ing off
any neighbors ;^) As a matter of fact, I got a
couple of long clapping applauds from the
next door neighbor(s) tonight and it was the
Green Mosnter that "broke the ice" for me
and this fairly new neighbor to actually meet
and get to know each other several weeks
ago in the first place.
Anywho, if you remember, this was the result of
my opening up the "G-10 blistering" thread a
few weeks ago. I think Phil Labud (spelling?)
brought up the aluminum shaft collars as a
possible solution for the flying electrodes
overheating to the point of scorching the
surrounding G-10 material of the rotary disc.
Well I think that it did at least improve this
situation and although I was only left with
1/4" of flying tungsten electrode "head"
sticking out from the collars, close examination
of the shaft collar "shoulders" didn't show
any obvious signs of the SG arc hitting them. They do
still get quite warm after a minute or two of firing
at around 20 kVA but I think that this has been
at least a partial solution to the overheating problem
that I was having.
BTW, it seems that my coil's output sparks don't
really get much longer after turning the variac dial
up past about 60%, just a whole lot more intense
and louder. I have probably just about reached the
spark length limit for the 12.5" x 49" long physical
size of my secondary coil and the 12 x 56" topload.
About 12 to 13 ft, maybe an occasional 14 or 15
footer is about all that I can seem to get out it, even
at >20 kVA, although they are very bright 12 or 13
ft. ground striking power arcs ;^0 Of course, I
don't normally set up an elevated grounded rod to
attract streamer/arc hits either. I just let 'em fly at the
surrounding ground surfaces ;>))) I may have to try
setting an elevated grounded rod out at say 15 feet
from the topload and see if I can attract "strikes" the
next time I run her.
David Rieben
----- Original Message -----
From: "bartb" <bartb@xxxxxxxxxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Friday, July 04, 2008 4:54 PM
Subject: Re: [TCML] Poly thickness
Hi David,
Ok, I agree with all but the distributed C. Maybe I don't
understand the terminology of the term "distributed capa-
citance" but I always assumed that it referred to the capa-
citance of what is formed by the dielectric qualities of the
wire's insulation between each adjacent winding (and the air, which
would significantly reduce the this distributed C, especially with a
space wound coil, wouldn't it?) Now I'm confused because I seem to
remember hearing the idea that the distributed C was INCREASED by
close winding the secondary coil (and that was supposed to be a bad
thing),
which seems backwards now that I think about it. It seems
the distrbuted C would be dramatically reduced by space winding the
secondary coil, since you are in effect incresing the dielectric
thickness and also dropping the dielectric constant
by adding more air (which has a dielectric K of 1) to the dielectric
Isn't the C of a dielectric system determined by C = K(.2249 x A/T)
Where K is the dielectric constant, A is the dielectric area, in sq.
ins.,
and T is the dielectric thickness in inches, and C is in uFd? Help :^/
By distributed C I'm referring to the resonator capacitance distributed
throughout the coil and affected by both internal and external bodies
and their relative positions. In other words, the total capacitance of
the resonator at resonance.
The coil is still the same diameter, length, proximity to top load,
ground, other external objects. The only thing that has changed is the
internal turns and space between turns. It's basically the plate area
has been reduced but the area between plates has increased (decrease
plate area decreases C, but increased area between plates increases C).
In this situation, it balances out (half of plate area, twice the
space). What changes is the inductance by a factor 4.
Even using Medhurst where C=KxD: D is diameter (which didn't change) and
K is based on h/d (which didn't change). You arrive at the same. You
could measure L, measure Fr, back calc C for both coils as described.
You'll end up the same, but it's easier to just model it, and the model
shows no change, but if you consider the wire and the spacing, it makes
sense.
I see "zero" benefit to spacewound coils.
Take care,
Bart
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla