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Re: TC Theory
Tesla List wrote:
>
> Original Poster: RWB355-at-aol-dot-com
>
> Hi Cabbott and all,
>
> Here are some thoughts about why I still say a transiently excited TC
doesn´t
> experience a resonance rise.
>
> Lets say:
> -------------
> FRes = 100kHz
> The coupling is so that after 5 oszillations the gap stops conducting.
> To keep things simple we will also say this is first notch quench.
> As soon as the secondary coil starts giving off sparks the Q drops to about
> 10-20.
> ------------------
>
> Now lets have a look at the whole thing on a sort of time graph:
>
> T=0:
> This is the starting point.
>
> T=0-50us:
> Energy is transfered from the primary to the secondary. The gap stops
> conducting.
>
> T=50-150us:
> The coil "rings" and the secondary starts to emit sparks. (It transfers its
> stored energy into the sparks). If the secondary did not lose energy at this
> time, we wouldn´t be able to get any sparks, right?
>
> T=150µs-10ms:
> Nothing happens. The stored energy has been used up to create ion
channels and
> sparks, etc.
>
> T=10ms
> The cycle begins anew.
>
> Looking at it from a slightly different angle: During 9850µs (out of 10000µS
> total) NOTHING happens in the secondary. There is no voltage present.
>
> It should be possible to simulate this on a computer, although it might
not be
> an easy task doing so from scratch. Any simulater gurus out there,
willing to
> try?
>
> If we now compare the "push the swing idea" to our Tesla coil, this would
mean
> we could collect and store a charge in the secondary COIL (in multiples
of the
> primary energy stored in the primary cap) every time the gap fires.
>
> This is NOT possible, because the secondary is absolutly dead in 98.5% of
the
> time, which means any "phase information" gathered, would be lost. Plus it
> would violate the energy conservation law. Output Joules can never be
greater
> than the input Joules. Any sort of transformer cannot MAKE power.
>
> A nice equation for Vout would look something like this:
>
> Ep = X * (Es+Et)
>
> Ep = 0.5*C*V^2 Energy in the primary cap
> Es = Energy in the secondary
> Et = Energy stored in the toroid
> X = Is an "efficiency" factor
>
> If the output where to experience a resonant rise the (Es+Et CAN NOT be
> greater than Ep !!) factor "X" would have to be greater than one ...........
> and I don´t believe this is possible. I think determining the "X" factor
would
> be very, very difficult. As a matter of fact I wouldn´t even be able to
guess
> an approximation for this.
>
> If there is a flaw in my theory, please do point it out to me. Otherwise I
> will stick to my comment that a spark gap driven TC DOES NOT EXPERIENCE A
> RESONANCE RISE.
>
> Coiler greats from germany,
> Reinhard
Can't agree with this! During each discharge period the secondary does
indeed experience a "resonant rise" in voltage, exactly as does any
other coupled circuit excited by a transient RF waveform. For the case
where the coupling factor is "magic", it the gap quenches "at the first
notch", nearly all of the energy originally stored in the primary
capacitor has been transferred to the capacitance of the secondary. The
secondary voltage for this case reaches a maximum at the time where both
the current and the voltage in the primary are zero. Many fellows have
posted theoretical and measured waveforms here, showing just this
behavior. For high values of coupling the secondary rise time is only a
few cycles, and almost all of the energy is transferred. For low values
of coupling the rise is slower, and more energy is dissipated in the
primary and secondary circuit losses.
Should mention that the "magic" values for k normally given are those
for the case when the UNCOUPLED resonant frequencies of the primary and
secondary circuits are equal. If they are not equal there will be
somewhat different values of k which meet the required conditions for
total energy transfer.
Ed