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Re: What is Kickback?



Hi Nick, Gary,

> Original Poster: "Megavolt Nick" <tesla-at-fieldfamily.prontoserve.co.uk>

snip, snip

> 3.Non-firing - when the sq does not fire the pri tank will 'res-up'
>to a huge voltage, if it is reso matched.

I would say the explanation is correct, but I wouldnīt call
this a true kickback, because it is not caused by the TC,
but rather through the effects of resonant rise (or just late
firing) in the LC primary circuit, so itīs not "coming back"
from the TC. However, this is just nitt picking a little ;o)

> 4.Primary Resonant rise - this is the simple resonant action
>within the primary circuit which experiences a Q factor rise
>(Not a direct Q factor rise as the seconday mtual inductance
>is not included in the Q calcs)

I doubt this will really add to kickback, because the primary
circuit has a pretty rotten Q factor. 5-10 at most when the
main gap is triggered and *maybe* 40-50 when not and only
if it is well built. "High-Quing" your primary will not really add
an increase in output spark length. Minimizing I^2R losses is
the real go-getter.

> I would also advocate a safety gap from the primary circuit
>to the rf ground as a better way of dealing with strikes to the
>pri. than the normal primary safety gap which under primary
>strike conditions can place the transformer under considerable
>insulation stress.

Sorry, but I canīt really see the difference here. If you have a
SG across your xformer, then it will clamp the xformer to *zero*
or a safe voltage. So why would your method provide an extra
measure of safety? As a matter of fact, IF you place a Sgap
directly across the primary coil, it will place a gigantic load (when
this gap fires) on your primary cap, as you have only the inductance
in your connection leads that will limit the peak amperage flowing
through your cap. If you are using thick and heavy wiring, this will
be in the sub ĩH range (meaning MANY amps, probably easily in
the thousands range). This is why I mentioned (sometime in the
beginning of 1998) using a SG with a series resistor across the
cap. That way, your cap and the xformer are protected and the
excessive voltage is bled off to the RF ground.

Coiler greets from Germany,
Reinhard