Re: Tesla Coil Blunders

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

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-uswest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi John C.,

I've tried to calc this in the past, but couldn't get it right. The
effective series resistance was not as easy
as I once thought it was. My personal sonotube coil is off by about a turn
from basic Wheeler/Medhurst calcs. I
find Gary's comment regarding E-Tesla 6 interesting in this investigation.
If E-Tesla 6 can truely identify "on
the mark" the frequency, then the answer is staring us in the face! (should
this be true for all our coils).

Bart A.

Tesla list wrote:

> Original poster: "John H. Couture by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <couturejh-at-worldnet.att-dot-net>
>
> Tesla Coilers may be making the worst of TC blunders when doing calculations
> for determining the operating resonant frequency of their coils. It is a
> well known fact that the calculated frequencies do not agree with the actual
> operating test frequencies. Many important design decisions are based on
> this unique frequency so it is important that it be correct. To circumvent
> this problem a fudge factor is used for all TC computer programs but this is
> only a bandaid for TC design.
>
> The equation that coilers use for finding the TC resonant frequency is
>
>       F = 1/(6.283 x sqrt(LC)
>
> The TC secondary circuit is an RCL circuit but the "R" is omitted by coilers
> in the above equation which may be the worst of TC blunders. In the Tesla
> Coil Construction Guide page 5-1 the complete resonant frequency equation is
> shown including the "R" parameter. It is also mentioned that the "R" reduces
> the resonant frequency and if the "R" is large enough there will be no
> resonant frequency. In other words the "R" could be the reason the operating
> frequency does not agree with the calculated frequency when the "R" is
> omitted.
>
> To my knowledge no one has ever determined how to find this very important
> "R" for an operating Tesla coil either by calculation or by tests. TC
> programs are hurting because of this lack of information.If anyone has any
> comments I would be interested in them.
>
> John Couture
>
> --------------------------------