Re: TC resonance estimation?

["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 Mike,
        The good news is that you can *choose* the frequency you wish 
to operate at and design a secondary coil to do it for you. Several 
simple equations and an idea of what you want to achieve are all you 
need. The bad news is that if you design for a low frequency and a 
small coil to do it, the secondary losses will soar exponentially 
which is not good, especially for a CW coil where RMS currents are 
typically higher than a disruptive coil.

     Medhurst, Wheeler are the names to remember and there must be 
plenty of data on what adding a particular size of terminal to a 
particular size of secondary does to frequency in the archives. The 
final *minimum* radius of curvature of the terminal will determine 
what output voltage you can reach (assuming copper losses are kept 
low enough) before the coil can break out with a spark.

Regards,
malcolm


On 17 Jul 2002, at 23:47, Tesla list wrote:

> Original poster: "Mike Panetta by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <ahuitzot-at-mindspring-dot-com>
> 
> I have looked at a couple of sites that have programs that calculate the
> resonance of a coil for you, and even an excel spread sheet that I think
> does the same, but I use linux almost exclusivly so I cannot really run
> any of these programs.  So I guess my basic question is, what in general
> would I have to do to wind a tesla coil that will resonate at a
> frequency lower then 150KHz?  I want to try my hand at building a direct
> drive SSTC with some specialized flyback type transformers I have, but I
> have no clue where to start really.  Do I need to know what the
> resonance frequency of the secondary of my drive transformer is?  How do
> I figure out the combined resonance frequency of the coil in this
> config?  The request for a low resonance frequency is because I want to
> use IGBT's instead of FET's (mainly because I have some already, and I
> know they work well to drive the flyback) and they only work up to
> 150KHz (well thats what the spec sheet says anyway...).
> 
> If possible I would like this to be a smallish coil, as its my first and
> I would prefer function over spark length to start with :)
> 
> Thanks for any help,
> 
> Mike
> 
> 
> 
> 
>