[TCML] Re: Spark gap Resistance

[Barton B. Anderson]

John touched on a key point here.

When the gap quenches at 1st notch, all the cap energy was transferred 
to the secondary in the first half cycle and was dissipated in the 
secondary and in sparks. If the secondary and top terminal are not 
capable of dissipating all the energy in the secondary, the remaining 
energy will transfer back to the primary "while the gap is still 
conducting" during the second half cycle. It will again transfer back to 
the secondary and hopefully be dissipated. This will go on and on until 
the energy has finally dissipated allowing the gap to stop conducting or 
quench.

If the energy is quenched by the 1st primary notch, there is only a 
single ring up "time" for the spark channel itself. If we quench on the 
2nd primary notch, the "time" of the secondary sparks are controlled by 
the ring up time between each spark and the energy bussed to the 
developed spark channels. It's not difficult to see that faster quench 
times may not always be preferred.

In second notch quenching, the secondary has rung up twice and produced 
a spark in each ring up and likely in the same channel as it is hot and 
ionized by the first ring up event. I expect the channel to be more 
conductive and possibly allow a little longer protrusion on the second 
ring up event.

But there is a limit. The second ring up has less energy than the first. 
I think the overall control mechanism is the air around a terminal (the 
medium the sparks are burning through) and the allowed energy in the 
spark channel controlled by the top terminal size and the energy 
transferred to the secondary.

When we increase pulse impedance by means of higher primary inductances, 
we are limiting the energy transfer time affecting the secondary's 
energy envelope over it's ring up, and in effect, helping to balance the 
secondary's ability to dissipate the energy.

Take care,
Bart






> The key to understanding this is that *all* the energy is always  transferred
> by the first notch no matter what.  But some of it comes back to the 
> primary if quench does not occur.  The spark streamer meanwhile  utilizes the
> portion that it can during the first transfer.  Thus a tight coupling  gives 
> longer sparks, regardless of how good the quench is (assuming no power  arcing).  
>