Re: Quenching question.

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

Original poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br> 

Tesla list wrote:
 >
 > Original poster: "Luke" <Bluu-at-cox-dot-net>

 > Imagine TC built with a gap that used external cooling of the gap to aid in
 > quenching.
 > This cooling is variable and can be turned up or down to achieve optimum
 > output.

No big problem with a variable-speed fan to cool the gap.

 >...
 > My question is this:
 > If a spark gap were made that could quench almost instantly after the arc
 > is established could it be too fast to allow the TC to give good 
performance?

Yes. If the gap doesn't refire when the voltage over it reverses for the
first time, little energy will be transferred to the secondary. It must
refire after the reversals several times, until the energy transfer is
complete.

 > In other words if the time the gap conducted were brought to a very short
 > time could it hinder performance of the TC?

Yes.

 > It seems that if the time were too short, current would just start to flow
 > from the capacitor to the primary coil then the gap could be made
 > to  quench when only 1/16 of the power from the capacitor has emptied into
 > the primary.  This would prevent the primary / secondary coils from seeing
 > very much of the energy in the cap.

Essentially, yes.

 > So do we want a gap that quenches real fast or do we want a gap that
 > quenches at just about the right amount of time?  We seem to go for a gap
 > that quenches very rapidly.  Could that be only because we can't get one to
 > quench fast enough yet, let alone one that quenches too fast?

We need one that quenches at the right time, just after the energy
transfer
is complete. Systems with high coupling require quenching after fewer
cycles, but never less than one full cycle of the primary voltage (for
k=0.6, used only in Tesla coils used for energy conversion, not to
generate sparks). With smaller couplings, the gap has more time to
quench.
With too low coupling, it can even quench before the right time.
I imagine that most coils quench after a few energy transfers, at the
second or third primary voltage notch.

An exact controllable gap can be made with active electronic devices
instead of the simple spark gap, if devices with suitable voltage and
current handling capacity are found.

Antonio Carlos M. de Queiroz