Re: What about this *Unique* Spark gap design??

["Malcolm Watts" <M.J.Watts-at-massey.ac.nz> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi Garry,
          A few weeks ago I thought about the possibility of 
using a contactless gap made of two counter-rotating plates to 
do the airblast job. Slightly different from your idea however:

On 7 Aug 00, at 11:40, Tesla list wrote:

> Original poster: "Garry F." <garryfre-at-pacbell-dot-net> 
> 
> I've been thinking of someof the problems that I keep running into when
trying
> to adjust my air cooled static spark gap.
>  
> The voltage required to start a spark, is much higher than that needed to
> maintain a spark.
>  
> A wider gap provides better performance at the cost of needing more
voltage to
> start the spark. NST's burn out and caps can get fried if this gap is too
wide.

A wider gap = more loss in the gap. One of the things that 
makes a rotary good is the fact that as conduction and pri-sec 
transfer proceeds, the electrodes are moving closer to each 
other.  

> If the current output of a NST isn't high enough, it can take longer to
charge
> up the caps up to the voltage needed to jump the gap and sometimes results in
> tesla output that looks "Unsteady" as the cap charge time becomes long enough
> to be noticeable.
>  
> In other words, if I make the gap narrower, the output is diminished, but
if I
> make it too wide, I get spotty output.

Diminished only from the point of view of initial firing 
voltage and cap energy. An ideal gap is one which fires at the 
desired cap voltage, closes completely together while the pri-
sec transfer proceeds (lossless) and then immediately stops 
conducting on completion of the transfer. Nirvana.

Regards,
Malcolm

> ---
>  
> It seems to me that a rotating flat piece of metal between the gap, might
yield
> good results IF the gap or rotating metal is adjusted so that the metal piece
> will narrow the gap to a point that a spark can be started, and as the flat
> piece of metal rotates, the gap is widened to allow maximum distance between
> the electrodes but not so wide that the NST or caps are fried. 
>  
> I imagine that there would be an optimum rotational speed that might be found
> by varying the speed of the motor.
>  
> I wonder of anyone has tried this kind of spark gap.
>  
> It might work great, or might stink, hard for me to say unless I try it.