Re: Primary Turns

[FutureT-at-aol-dot-com (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

In a message dated 6/13/00 6:32:27 PM Pacific Daylight Time, tesla-at-pupman-dot-com 
writes:

> Original Poster: "Kamil Kompa" <czlonek-at-polbox-dot-com> 
>  
>  Hi !
>  
>  What is the minimal and maximal number of turns in TC primary (between
>  what numbers of turns in primary Tesla Coils are working the best)?
>  

Kamil,

For the best results, the primary should have a high surge impedance
which means there will be a rather high inductance compared with
the capacitor size.  A high primary surge impedance will reduce the
gap losses.  This suggests the following:

1)  If you don't care about getting the longest spark for the input
power, you can use a small capacitor and a higher break rate.  This
will permit you use to use more primary turns.

2)  If you do want the longest sparks for a given power input, then
you have to use a larger capacitor and a lower break rate.  This makes
it harder to use a lot of primary turns, but it can be done.  Simply use
a lot of secondary turns too, using thinner wire.  Another approach is 
to make the 
secondary and primary wider in diameter, this will increase the
inductance without using a lot of primary and secondary turns, but
it will increase the secondary self C, and my tests indicate that
this reduces the spark output also.  Because of this, I prefer to
keep the secondary rather tall and narrow, and use a lot of turns
of thin wire, and use relatively thin wire on the primary too, with a
lot of turns.  I often use from 14 to 25 turns or more in the primary.
You can see an example of this type of construction and a description
of the results at:

   http://members.aol-dot-com/FutureT/TT-42index.html

Cheers,
John Freau