Re: QTC Question

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

Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz> 

Hi Carl,
          Not having used QTC (whatever that is) I can probably offer
from experience some insight into what is going on:

On 4 Oct 2004, at 19:09, Tesla list wrote:

 > Original poster: "Carl Litton" <Carl_Litton-at-hilton-dot-com>
 >
 >
 > To anyone who has used the QTC calculation sheet for coil design:
 >
 > We are working through primary design parameters and some confusion
 > has arisen.  The spreadsheet has one calculate the L*C of the
 > secondary to determine its resonant Freq.
 >
 > Then it goes to a capacitor calculation for impedance matching with
 > the PSU - which we understand to be the desired capacitor for the
 > primary tank circuit.

Well desirable as far as the transformer is concerned. This matching
value used to be gospel for the cap value but you can actually do far
better energy-wise by using a much larger value (start with
SQRT(2).C) for example. There is more to this concerning erratic gap
firing but that's really another issue.

 > Then one would think next the L*C of the primary is done so that the
 > resonant frequency of the primary equals the loaded frequency of the
 > secondary.
 >
 > However, it begins asking for the 'capacitance chosen.'  What could
 > that mean?  This is a derived figure not a chosen one, as it would
 > depend on the primary design, which has not yet been determined.

I infer that one can choose a capacitance other than the transformer-
resonant value as I've suggested above. Knowing the chosen value, one
can then calculate the tank inductance to fulfil the resonant coil
requirements. That'd be my interpretation anyway.

Malcolm

 > If you know what we're missing here, please explain.
 >
 > Thank you,-
 >
 > Carl Litton
 > Hilton Hotels Corporation
 > 901-374-5747
 >
 > -----Original Message-----
 > From: Tesla list [mailto:tesla-at-pupman-dot-com]
 > Sent: Monday, October 04, 2004 2:10 PM
 > To: tesla-at-pupman-dot-com
 > Subject: Re: some new ideas for the SSTC guys
 >
 > Original poster: "boris petkovic" <petkovic7-at-yahoo-dot-com>
 >
 >
 > --- Tesla list <tesla-at-pupman-dot-com> wrote:
 >
 >   > Original poster: "Dr. Resonance"
 >   > <resonance-at-jvlnet-dot-com>
 >   >
 >   >
 >   > Problem --- Exploding IGBTs when they are hit with a
 >   > sec - pri spark (Terry
 >   > Blake's coil terrible demise at our Teslathon).
 >   >
 > Use magnifier configuration (3 coils in topological
 > sense).Problem solved.
 > My 2 cents,
 > Boris
 >
 >
 >