Re: LTR vs. more primary turns

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Chris,

On 3 Dec 2002, at 22:36, Tesla list wrote:

 > Original poster: "Chris Roberts by way of Terry Fritz 
<twftesla-at-qwest-dot-net>" <quezacotl_14000000000000-at-yahoo-dot-com>
 >
 >
 > Hello, it's me, the guy who can't build a tesla coil right. =P
 >
 > Since my big coil is out of order for a while, I'm going to take some of
 > the caps off of it and use them to build a 4kv, 38ma mini coil. However, I
 > ran into a problem. We all know how a LTR cap increases the coil output,
 > but as I was running calculations, I found that the higher the tank
 > capacitance the fewer the number of primary turns it required to reach
 > resonance. But I read on John Freau's website
 > 
<http://hometown.aol-dot-com/futuret/page5.html>http://hometown.aol-dot-com/futuret/page5.html 

 > that using a higher number of turns on the primary will increase primary
 > surge impedance, and will reduce spark gap losses. Is this true? If it is,
 > then I pose the following question: Using a given secondary frequency, is
 > it better to have an LTR cap with relatively few primary turns, or to have
 > a smaller tank cap and more primary turns? Thanks for your infinite
 > knowlege and wisdom.

What John said is true. Starting from a given secondary is not the
best way to design a good coil. You should be starting from the
capabilities of your chosen supply. That is exactly how I design
coils. Once you've wound the secondary, you're stuck with it for
better or worse.

Regards,
Malcolm