RE: Toroid size selection

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

Original poster: Thomas <tom-at-pwrcom-dot-com.au> 

Original poster: "Luke" <Bluu-at-cox-dot-net>

I just joined the group and this is my first post.
I have played with TC's bout 12 years ago and my last one took up too
much
room for me at the time so I dismantled it.
I have regretted it since.  So now its time to make another.

My question is what is the best method / formula for selecting a toroid
size?  And why?
Various opinions and methods would be appreciated so I can get an over
all
view of what everyone thinks.

I will be using 2 NST's in parallel each rated at 15KV 60mA.  For a
total
of 1800 watts.
The capacitance I have chosen is 0.0214 micro farads.
I will be winding a coil with a diameter of 8 inches and a 36 inch coil
length.
How do I go about figuring out the best size toroid with the above
information?

Thanx.

Luke Galyan
Bluu-at-cox-dot-net
-----------------------

Hi Luke, there are many conflicting requirements for a top load, here are
two:

1) A larger toroid gives a higher breakout voltage and hence can give lager
streamer length.

and

2) A smaller toroid will give a lager Cp/Cs ratio (which is the voltage
gain) and hence the potential for longer streamer length.

In practice you want to select a top load that will enable you to tap the
primary coil at a reasonable number of turns (5 to 10), for coupling and
current (gap loss) considerations.

As you know most of your other parameters, plug them into javatc and have a
play with different top load sizes (almost as good as real experimentation):

http://www.classictesla-dot-com/java/javatc.html

Good to hear you have coiling fever again!

Tom L.