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Re: Core Material



Subject:  Re: Core Material
  Date:   Thu, 1 May 1997 16:52:19 +0500
  From:   "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com>
    To:   Tesla List <tesla-at-pupman-dot-com>


On Wed, 30 Apr 97 21:18:36 UT Robert Davis
<Davis_Lewis-at-msn-dot-com> wrote;

> Hello Coilers,
> 
> I am about to start building the secondary of my first (small coil), I
> have some Acrylic rod and thought of using this for the former.  Being
> soild I  would be able to screw and bolt connections to the former.  I
> would think losses would go up slightly as opposed to sealed tube
> construction but not enough to be a problem.  Would there be any other
> problems using a solid plastic core?

Hi Rob, by acrylic I assume you mean persiplex or what we here in the 
states call plexiglass, if so there is nothing wrong with it as a 
secondary form. I amonly concerned that you may be using it to build 
a long thin coil which is a very inefficient design! The 
length/diameter ratio of a tesla coil should never be greater than 4 
and is best around 3 (minimum copper losses). Look back at all of Dr. 
Tesla's coils and you will see thay were all barrel shaped. 

>Also, I was thinking about half wave coils, not many people seem to
>build these.  Why is this?

For several reasons Rob, first you need twice the amount of wire for 
your secondary but you don't get twice the output! Secondarily with 
the secondary lying horizontaly it is difficult to get long sparks 
from it since ground is very close. There was a picture in one of the 
back issues of T.C.B.A. that showed a huge 1/2 wave coil mounted 
verticaly but its output was less than half its length, now a days
it's not uncommon to see 1/4 wave coils putting out sparks of over 
twice the secondaries length!

                               Sincerely

                                \\\|///
                              \\  ~ ~  //
                               (  -at- -at-  )
                        -----o00o-(_)-o00o-----
                           Alfred A. Skrocki
                   alfred.skrocki-at-cybernetworking-dot-com
                             .ooo0   0ooo.
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