Re: New to list, a few questions

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 7/29/01 5:55:58 PM Eastern Daylight Time, tesla-at-pupman-dot-com 
writes:

> called Skycraft.  They have everything electronic and
>  > mechanical there and I do mean everything....but they were sold out of 
> neon
>  > sign transformers!  That's something I still have to find.

Sean,

Welcome to the list.  A friend of mine used to go the the skycroft
store in FLA.   Hamfests are a good source of parts too.  More
comments below.
>  > 
>  > Now, a few questions:
>  > 
>  > 1) Is there any physical limitation to a rotary spark gap if the 
> mechanical
>  > aspects of it were theoretically unlimited?

I've found the best results using rather low break rates of around
120 breaks per second.  Some folks like to run at 240 to 600
bps or so, but nothing is gained by the higher break
rates, except the sparks may appear more frantic.
>  > 
>  > I have a brushless D.C. motor ( approx. .5 HP) that produces 5,300 RPM 
per
>  > volt.
>  > 
>  > 2) What effect does a higher frequency spark gap produce?   What is the
>  highest

The gap's break-rate, and the frequency of the coil are two 
separate issues.  Usually the gap's break rate is around 120 to
600 bps, but the resonant frequency of the coil is usually somewhere
around 50kHz to 600kHz.  Lower resonant frequencies are 
probably a little better than higher ones.

If the gap's breakrate is higher, then the capacitor can be smaller
for a given power throughput.  I've found the best "efficiency" at
lower breakrates around 120 bps.

>  > resonant frequency anyone has ever heard of anyone producing with a Tesla
>  coil?

By making the coil very small with fewer turns of wire, the 
frequency can be made high, for instance 3mHz or so, but these
coils are generally not very "efficient".

>  > monster so I ordered the plans for BTC-4 and will make the it my first 
> coil project.  

I seem to remember hearing that the BTC-4 is a somewhat
inefficient coil.  Although I think some folks liked it.

My website is at:  
     http://hometown.aol-dot-com/futuret/page3.html

My TT-42 coil is there, toroids, theory, etc.

Cheers,
John Freau
---
>  > Thanks for any constructive replies.
>  > 
>  > Sean