# Re: Insulation

```
From: 	Rodney Davies[SMTP:rgd872-at-anu.edu.au]
Sent: 	Friday, August 01, 1997 7:48 PM
To: 	Tesla List
Subject: 	Re: Insulation

Hi Richard,

On Thu, 31 Jul 1997, Tesla List wrote:

>
> Sent: 	Thursday, July 31, 1997 2:57 PM
> To: 	tesla-at-pupman-dot-com
> Subject: 	Insulation
>
> Hi,
>
> I want to know how a person can stop your secondary's coil last winding from
> discharging. I have a small 1 inch diameter iron ball on top as a discharge
> sphere. But at the last turn on my secondary there comes a 4 inch spark out
> and that energy is lost and aren't going to my small sphere.
>
> Anyone have Ideas on how to overcome this problem. I don't want to use a
> large torroid to make an shielding effect.

Question - what is the diameter of your secondary?

If it's greater than 1 inch, then you're going to have this effect,
however, you must at least 'trick' the coil into thinking there's a bigger

Ok, take a length of copper pipe and bend it into a perfect circle. (Best
to take it from the pre-coiled type copper you get from gas supplies or
plumbing stores)

Make this circle slightly larger than the diameter of your secondary, say
with 1/2" spacing between the loop and the outside of the secondary.

Next, Make a frame structure such that it will allow the circle of copper
to hang inline with the top turn of the secondary, aswell as connected
with the 1" ball...

Ok, perhaps a diagram can help... (I love ascii art! :-)

Top View -
/~|~\
/ /~|~\ \
|---( )---| <---- Copper pipe loop with a cross frame.
\	\_|_/ /
\_|_/

Side View -               _
(_)       <---- 1" ball
____+____
| ___|___ |   <---- Cross frame support.
o=========o   <---- Copper pipe loop inline with top
|     |           turn.
|     |
|     |     <---- Secondary Coil

This is basically increasing the effective diameter of your terminal
without actually building a toroid.   I've seen this used on a coil once
before. Streamers were long and no arcing from the top turn occured.

Hope this helps...

Catchya!
Rod

```