RE: Simulating Load for SSTC Coil Simulations - Terry Fritz model?

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

Original poster: "John H. Couture" <couturejh-at-mgte-dot-com> 


Terry -

Your measurements of the impedance of the brush discharge of a TC is opening
up a whole new territory of TC research. I believe this research was first
started by the Corums several years ago and was briefly covered in some of
their writings. You said you were able to tune the coil with ZERO watts
reflected. This would refer to the VSWR of the coil. The VSWR graph for
radios and Tesla coils is shown in the Tesla Coil Notebook. The VSWR for
radios differs from Tesla coils because radios feed a resistive antenna load
and Tesla coils feed secondary terminals which are a capacitive load. The
basic equation is

     VSWR = (Vf+Vr)/(Vf-Vr)

This is related to the Q factor by

      Q = (pi/4)x VSWR   Q = pi/Log dec

The Q factor for 10% ringdown is

      Log dec = ln(a1/a2) = ln(10) = 2.3026
      Q = (pi)/(log dec) = 3.14159/2.3026 = 1.3644 per cycle

To my knowledge there has been little TC work done in this direction so it
will be interesting to see how the tests compare with the graph. Are there
any other coilers that have looked into this TC subject?

John Couture

--------------------------------


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Thursday, January 29, 2004 11:41 PM
To: tesla-at-pupman-dot-com
Subject: Re: Simulating Load for SSTC Coil Simulations - Terry Fritz
model?


Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi Dan,

If it is a MicroSim model, I could look at it here and see if I can find
anything wrong.  This might be of some help too:

http://hot-streamer-dot-com/TeslaCoils/MyCoils/CWCoil/CWImpedance.txt

Cheers,

          Terry

At 08:46 AM 1/28/2004, you wrote:

 >Steve Ward and myself have been working with a PSPICE SSTC simulation.
 >I currently been basing my resonator model off
 >the model Terry Fritz has developed and I have used real-world numbers
 >both measured and calculated for my particular
 >resonator.
 >
 >However, during simulation, I don't believe the model is providing
 >enough of a load.  I'm getting peak currents of over 100A during max. RF
 >envelope and RMS currents of 40A+ (about 9kW+) over many periods of
 >operation.
 >
 >Do you think the discrepancy could be due to the fact of using an ideal
 >model for the input 240VAC power source or is it
 >a limitation of the model itself.
 >
 >I want to simulate the death out of this new inverter circuit, but
 >without a valid resonator model, i'm basically SOL.
 >
 >Any thoughts???
 >
 >Dan