Re: Harmonics

Tesla List wrote:

> Original Poster: RWB355-at-aol-dot-com
> Hello Cabbott, all,
> You wrote:
> .... this is akin to pushing a swing every time it rocks back.
> This WAS how I thought a Tesla coil worked a while ago, too. However, new
> discusions and thoughts have lead me to believe this is NOT how a spark gap
> driven Tesla coil works.  I guess you are talking about someone sitting on a
> swing and a second person gives the swing a push (with the equal amounts of
> energy each time) each time it comes back to the "pusher".

This is not what i was saying.... i was simply saying that the primary
feeds the secondary, even though the PRIMARY is the one that is struck like a
bell. its the L-C circuit of the cap and the primary that make it ring, even
without the secondary.

> You store an "x" amount of energy in the primary cap. When the gap fires
> energy is transferred to the primary coil. The magnetic field generated by
> this surge induces a voltage across the secondary (inductive energy
> Not all of the primary energy is transfered into the secondary during one
> oszillation, so you want the tank circuit to be able to "swing" a few times
> (more on that in a minute), before the gap stops conducting.

while the gap conducts, you dont want the circuit to swing at all!!  if it
to swing while the gap was still conducting, it would NEGATE the effect and
whole process would be absorbed and wasted.  thats why you want your gap
to be fast fast fast, so you can quench it good enough to make the primary
ring...  which would be 1/4 of the primary resonant waveform....

> This is the
> maximum amount of energy you are able to store in the secondary. Now you can
> transfer this energy into something usefull (like making sparks).
> A toroid sitting on top (capacitor) of the coil stores the charge and will
> prevent the voltage from breaking out immediately. The bigger the toroid,
> higher the voltage it can store, and the longer it takes for the charge
to be
> stored because your coil cannot deliver the voltage needed for a full charge
> in one cycle. This means the coil will not arc after every bang. If you have
> an excessively large toroid, you will never achive an arc, because you canīt
> charge it high enough for breakout to occur. So, for hottest and longest
> sparks, you will want a toroid which will promote breakout at about
70-90% of
> the highest voltage your coil can make.
> You want the spark gap to stop conducting exactly at the point where all
> energy stored in the primary has been transfered to the secondary. This
is the
> way I understand first notch quenching. Letting the gap conduct any longer
> will force the secondary to return some of its stored energy back into the
> primary, which means losses and therefore a shorter spark.

im with you there...

> I think a better picture of a spark gap driven Tesla coil would be a hammer
> and a bell. Your hammer is the primary circuit and the bell is your
> coil.

a better way to put it is "the hammer is the GAP firing, and the bell is the
primary-capacitor circuit.  the bell next to them both is the secondary, which
vibrates by conducting the sound waves from the primary bell"

> the bigger the hammer, the "harder" the bell rings, which is one reason
> why I like using a big cap and high RF currents as opposed to a high voltage
> and a small cap. This, of course, also has to do with the fact, that I am
> stuck with 7.5kV NSTs (at least 6 of them in parallel can deliever 600mA) at
> the time. The problem with the low voltage / high current are the higher
> losses involved (IxIxR), so it might be a win or lose situation in the end.

Gosh man, thats too bad!! 7 kv??

> The spark gap driven TC is not being continuesly fed with RF. Rather, a gap
> driven TC is a pulsed device. A CW (e.g.:tube driven) coil might be able to
> experience a resonance rise, although I am not quite sure of this, either.

me neither!

> A tube coil and a small magnifier (I will have to investigate what make a
> maggy tick) are on my long list of "still to do" things. Before I do this,
> however, I want to get my 8" coil shaped up. Considering that I am (during a
> testing phase) only dumping 0.22J into it and using almost no topload (maybe
> 1-3pf at most) to store the charge, I think my present spark length (long
> to maximum, of course) of 20" is okay.
> Your special setup causes interference which leads to an incredible voltage
> difference (you are using different wavelengths) between the two toroids.
> is why it should give you some really awesome sparks. If I am thinking
> correctly, firing two seperate coils 180° out of phase would get you similar
> results.

Not so!  two secondaries at 180 degrees will just make a higher voltage
effect of
the same frequency wave. Having a slower  wave secondary charging up the
to suddenly see a very low resistance of the smaller coil next to it, will
suddenly dump it's slow wave energy into the smaller coil in an infinetesmally
small amount of time.  This creates tremendous current densities in the space
between the coils, which is what creates ball lightning. (based on my

Thanks reinhard,