Re: What is Kickback?

Hi All,

> Original Poster: "Reinhard Walter Buchner" <rw.buchner-at-verbund-dot-net>
> 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)
I was just including in the 'kickback' theme anything that introduces
potentially dangerous spikes etc. into the primary circuit.

> > 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.
It does realise a small voltage gain - as you said the high R of the gap
wrecks the primary Q factor but it does still exhibit some resonant rise.

> > I would also advocate an extra 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)
Not across the primary coil, from the pri outer turn to sec ground.
> 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.
Simple, the Sgap from the primary circuit to the Secondary RF ground
protects from a pri.-sec. strike  much better than a normal safety gap
across the primary rails because when it fires the primary cap is not
discharged so it does not disrupt the primary circuit so much and place
undue stress on the caps and transformer insulation as a normal safety gap
does.  This works because the pri. and sec. have seperate grounds.
Your point about the safety gap is totally valid, a while back my safety gap
blew a bunch of caps so from then on I have taken to putting a coil of 8
guage wire in series with the safety gap to limit the peak current and have
had no problems since.
> Coiler greets from Germany,
> Reinhard
Nick Field