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Re: Tesla simulations vs. scope traces (fwd)


From: 	Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: 	Sunday, December 21, 1997 4:29 PM
To: 	tesla-at-pupman-dot-com
Subject: 	Re: Tesla simulations vs. scope traces (fwd)

Hi Scott,
          Good to see you post again. What you say is definitely
listened to with great interest by myself. In particular....

> 4) A distributed ladder network of series inductors simulating the bottom of
> the coil equal to the total secondary inductance/2 then /4 ,/8, etc..with
> capacitances to ground starting at the top equal to total secondary self-
> C/2+Toroid-C then self-C/4,/8, etc...showed a 91.58KHz component for the
> Inductor L7 at the top of the coil, and also 1,2,3,and 4MHz spikes for the
> Inductor L1 at the bottom of the coil...simillar to the scope traces from the
> real coil.

I take it then that that model is not complete throwaway material at 
this stage?  I was kind of hoping somebody would measure the 
responses. Good stuff!

> 5)  A resistor between the top C of the secondary and the toroid-C (100ohm)
> resulted in the removal of the higher frequency components in the AC analysis.
> Hmmmmm....what if?

Yes - something to be tried for sure! 
 
> 6)  Both the scope traces and the PSPICE simulations showed the high frequency
> components are of at least 3 to 1 greater magnitude than the approx 100KHz
> component.  I think this may be the secret of the magnifier.  If you tuned the
> extra coil such that it's res freq is equal to the L1 ring-up, you could get 3
> times the output?????

Some crude experiments convinced me early on that making the 
resonator ring at Fp was the way to go IF the pri was tightly coupled 
to the secondary (non-resonant transformer action). On receiving the
CSN a couple of years later, I see that Tesla also had to fall back 
on this mode of operation for mags. Other experiments show that with 
a loose coupled driver, things are much more complex (and not worth 
the effort) as then the secondary and extra coil have to be looked at 
as a single resonant entity with a discontinuity between them. I'd be 
interested to see a model of such a situation. People trying this
way of doing things have found that tuning is hard to predict and I 
think this has given rise to considerable mysticism about magnifiers 
whereas in fact they are fundamentally quite simple.

> I am building an extra coil for res at 4MHz to test this (without any coating
> so I can add or remove windings for tuning.)
> 
> I can't do any more tests until I rebuild my RSG (The cold weather caused some
> negative thermal expansion, and hence, a gap crash)
> 
> The high frequency component of the spectrum is based somewhat on how the
> resistance is distributed along the other components, since my simulations and
> the scope traces don't match as of yet, the correct distribution I have yet to
> find.
> 
> I will post images of the scope traces, PSPICE circuit, and PROBE output on my
> web page http://members.aol-dot-com/rscopper/index.htm as I get them formatted.
> 
> Stay tuned.......
> 
> R. Scott Coppersmith

Thanks indeed for posting.
Malcolm