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,

Tesla list wrote:

> Original poster: "John H. Couture by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <couturejh-at-worldnet.att-dot-net>
>
> Bart -
>
> It appears that there are two TC secondary circuit resonant frequencies
> depending on whether the TC is operating at high voltage and high current or
> not. This is important for a TC computer program because the program
> calculates the number of turns for the primary coil. With two resonant
> frequencies which primary turns should be calculated by the program?

At this point in time, I think the low V and I (higher F) should be used.
As you mention below, it's not a big
deal. I dont' think were ready yet for a high voltage and current Fr in a
program. There are a lot of variables
that will come into play. Possibly a fudge factor could be used now to ball
park the number. I think more needs
to be understood in the realm of full proximity effects (all
internal/external objects) and how this effects R.

E-Tesla 6 is the route for this at this time. I was starting to go through
the code last week (E-Tesla 6) but
got sidetracked. It would be good to merge Fr from this distribution
profile into our programs. This will help
identify some of the ghosts as more users build coils. But I personally
need to figure out the method used in
E-Tesla 6.

Take care,
Bart

> Of
> course this is not a big deal because the primary usually has plenty of
> adjustment, but would be of concern for Tesla coil designs that have fixed
> primaries.
>
> John Couture
>
> ----------------------------
>
> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Wednesday, March 28, 2001 8:49 PM
> To: tesla-at-pupman-dot-com
> Subject: Re: Tesla Coil Blunders
>
> 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
> >
> > --------------------------------