Re: Gap Quenching.
Sent: Wednesday, September 10, 1997 4:56 AM
Subject: Re: Gap Quenching.
<< Following John Freau's note on quenching, I thought I'd add some
> comments and a helpful hint based on experience with my modified coil.
> I'll throw this one out for a consensus vote: John mentioned two
> types of quench. I also think there are two types. From my notes, the
> first is the ability to put the gap out at a precise time (e.g. first
> notch quench) which directly affects pri-sec transfer. The second is
> merely to ensure the transformer doesn't power-arc in the gap. With
> regard to this second one, I've noticed this becomes necessary when
> the Q of the primary gets high enough and secondly, if you are using
> small values of primary capacitance that don't seriously load the
> supply transformer. To make my coil run properly in its modified
> state, I am hoping to run a jet of compressed air through the gap
> (there is an on-tap source right next to the coil). I have yet to
> obtain the fittings.
> Incidentally, the no-breakout envelope has now started to assume
> a log decrement of sorts indicating that the new frequency is getting
> too low for the wire diameter used in the resonator. It now runs at
> 121kHz whereas the design was originally for 145kHz. If I'd known
> then what I know now I would have used bigger wire. My vote of thanks
> to Richard Hull for the pioneering work on large terminals.
Thanks for these helpful hints. I've done relatively little work using
static gaps. I agree, preventing power arcing is another sort of
quenching, but it is one I did not discuss in my original posting.
I had discussed the use of too much air, which prevents the coil
from firing steadily...some people seem to call this overquenching.
They may think that they are quenching too soon, but in reality they
are using so much air, the gap cannot fire regularly. So I would say
there are then three types of "quenching". I put quenching is quotes
since the last type I mentioned is not really quenching, but a
prevention of firing, so I also refer to it as "overquenching" in quotes,
since it really isn't overquenching at all. It all depends on how one
defines quenching I suppose.
Regarding the log decrement you're seeing due to the thin wire, do
you think this will adversely affect the spark length in an actual