RE: New Three Inch TC Finished! But I Still Need Some Help!

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jim-at-jlproduction-dot-com>

Hi,

It was suggested to me to use the old fluorescent light on a stick
routine and that worked well for me.

Just tape one to a loooong stick and hold it near the toroid. As you
make adjustments and it approaches tune, the bulb will glow brighter.

I also noticed on my coil that the sweet spot is VERY small. As little
as a 1/16 of a turn off and it's a turd. Also of note is my spark gap
roars loudly as tune gets close. Between the bulb and the noise you can
find the spot with some work. Start in 1/2 turn increments and then 1/4
and 1/8 etc.

Jim Layton
www.jlproduction-dot-com/forum



-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Sunday, March 09, 2003 9:13 PM
To: tesla-at-pupman-dot-com
Subject: New Three Inch TC Finished! But I Still Need Some Help!

Original poster: "tmoore by way of Terry Fritz <teslalist-at-qwest-dot-net>"
<tmoorezz-at-adelphia-dot-net>

Hello Everyone,

       Well  I finished a new coil, it is a 3in system that runs on a
single
depotted 7.5/60 francfomer, it used to be one of the transformers with
ground fault protection. I use my new PSU its noting fancy just a variac
with a few switches. Well I need some help again I have been trying to
figure out were to tap the primary coil by visual observation of
streamer
length and behavior and it is quiet perplexing. My problem is I think I
have to much topload for break out, see when I taped the coil -at- 9.25
with a
break out point it produces long bright strikes to near by pair of metal
crutches.  Now when I remove the break out point the tesla coil wont run
even at full power, then I need to tap it around 7.5 turns to get any
break
out from the toroid, and there are allot streamers that are short(around
1.5
feet) very pail, with the break out point I get 40-44 inch sparks
regularly
to the crutches. Now Ed Sondermans Tesla Cal says it needs to be taped
around 10 turns. I think when I taped it -at- 9.4 or beyond the sparks
shortened and then will stop when tapped around 9.6turns. Ok how do you
tune
by visual inspection?? Is it in proper tune when the break out is on but
there are
streams COMING off the toroid on a few random places despite having a
break
out point were most of the streamers go, also streamers not quite as
bright
when they strike the crutches?? OR is it in tune when streamers only
come
from the break out point and are slightly more intense when they hit the
crutches and slightly more frequently?? I REALLY would appreciate if
some
one could answer those question and describe exactly how to determine
whether the coil is in tune by visual observation of streamers.

Here I'll give you a run down of my coils specs.

Topload
Two toroids made from flexo Al ducting
#1=19in wide by 3.375in across for 19.83pF
#2=12in wide by3.375in across for 13.35pf
So then what's is the total?? Its 33.18pF CORRECT???? That's a question
cause am not sure!
There spaced aprox .5in away from the top and bottom of each other btw
the
smaller one is on the bottom.

Secondary
Length=17.25in wound with 28awg enamled wire
Diameter= 3.5in pvc pipe coated with polyurathane
L=24.7mH (Measured) That makes it 71.25 turns per inch

Primary
IND=6.5in
OD=15.375in
Spaceing=Turns out to be around .29 on average between turns
Wire= 0.162in
Max turns=10.125 Measured 32uH max but Calculated its 34.2uH i think my
New
DMM is off cause the lowest seting is 2mH

Capacitor= Maxxwell pulse rated 35KV at 30nF Measued value=30.2nF
With a satfey gap set at 0.28125in wich fires ocasonaly

Spark Gap
Spaced total 0.1875in with 3 gaps and 4 copper pipe peices 2in wide by
1.125in diamither enclosed in a box fabricated from plastic cuting board
cooled by a 3in fan

Transfromer
Depotted Fance modified for matching to the capcitor, Some of the shunts
were removed, and i actualy submerged and soaked the tran in semi-gloss
polyurathane then let dry several times
I out=87.8mA
When the tesla coil is runing the amp meter waves backanforth between
8-13amps

       Ok i have tryed to figure out were to tap the primary coil by
puting
figures in to the formula F(KHz)=1/(2*pi*(sqrt(L*C))).  When I put in
the
numbers for the secondary with out the adding on the self capacitance of
the
secondary only the topload I get 176.17KHz secondary resonance, and when
I
change the figures for the primary coil to match the secondary I used
the
figures 30.2nF for the tank cap and it would take 27uH to match the
secondary.  According to Ed's tesla cal it would take 9.03 turns to get
27uh
of inductance, also it says I would need to used a 41nf tank capacitor
witch
is not the value of mine, so what is going on?  Also according to Ed's
tesla
cal I would need 10.4 turns to match my 30nF capacitor, which is bad
cause I
only have 10.1 turns max and when I tap it there it doesn't even
resonate
and the spark gap wont fire, id have to say it appears to operate best
when
tapped from 8.6 turns to 9.25 turns. Is this because of my topload?? Is
it
too bigg?? or is it that there is some formula to figure out the total
capacitance of the two toroids?? Like would it be the average of the
series
and parallel values??  So could some one help me!! I would like to have
it
in perfect tune before trying to maximize the spark length.

       Also I was wondering if there is a formula to figure out the
voltage
need to breakdown across the space in the spark gap, so that I know what
voltage the spark gap will fire at regularly. So far this system has
been
very agreeable and well behaved, there have been no racing sparks or
secondary to
primary strikes, and streamer length and power is quite impressive. I
have
also taken some terrific pictures Ill post some of them in a folder at
http://hot-streamer-dot-com/nolan/threeintc/ I really need some help on this
so
I appreciate your help greatly. Thanks.


Nolan Moore




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