Re: [TCML] Spark gap Resistance

["Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>]

I think Chris brings up a "very" valid point! The problem is, it is 
experience that drives the idea of a higher surge impedance. There's a 
reason it's termed "surge" impedance. There is a difficulty at quenching 
after the first notch. Those who have done this have reported in the 
past (from my memory) that they had better sparks lengths on 2nd or 3rd 
notch quenching as compared to 1st notch quenching.

Chris, several years ago, 1st notch quenching was the assumed ideal and 
we tried to do that for all the reason's you stated. What was found is 
that 1st notch quenching was not easy. Then, we found that when it 
occurred, it wasn't "wonderful". How could that be? Well, losses of course.

It's difficult to figure out and in my mind, it's still "not" figured 
out. We do know that when the surge impedance is increased due to higher 
inductance, we can get better spark output. But, there of course is a 
limit. It is counter-intuitive to physics when all the pieces of the 
puzzle are not accounted for. The only way "I" personally can explain it 
is that the losses incurred during energy transfer in a single notch 
arena are huge. Now, are those losses in the gap? Are they also shared 
in the secondary or primary to a large degree? The question is "where 
are the losses and what is their distribution" in this 1st notch quench 
situation?

Were talking about high energy pulse currents. If there is an escape 
route, high energy pulse currents will find it.

It seems to me that what we are doing is increasing energy transfer time 
to a degree in which the secondary and spark gap can "handle" the energy 
as a combined system. I believe that when we attain first notch 
quenching, we are simply releasing energy that is not being accounted 
for. It's not getting to the sparks, so it's a loss somewhere else.

Take care,
Bart

FutureT@xxxxxxx wrote:
> In a message dated 11/19/2007 6:54:37 P.M. US Eastern Standard Time,  
> list@xxxxxxxxxxxxxxxxxxxxxxxxx writes:
>  
> Chris,
>  
> If the current is less overall, then the gap losses are  lower.  Using a high 
> impedance
> primary results in less overall current and less overall losses.  When  more 
> inductance
> (more turns) are used in the primary, the inductance increases more than  the
> resistance increases, thus the primary losses are reduced.  The Q is  higher.
> The result is that
> both the gap losses and the primary losses are reduced.  Of course  this only
> works up to a point.  At some point the secondary wire will be  too
> thin and will show high losses.
>  
> Generally low frequencies are believed to be more efficient in  producing 
> long sparks.
> Maybe something in the range of 30kHz to 150hHz.  Also at higher  frequencies,
> it's harder to achieve a first notch quench.  The sparks themselves  may grow
> better at low frequencies.  
>  
> Large coils are generally more efficient than small ones.
>  
> Tank caps generally are able to provide their current fast enough for
> TC operations.  
>  
> Generally high breakrate coils need more input power to produce a  given
> spark length.  It's not known exactly what breakrate is best.  It  may vary
> somewhat among coils.   Somewhere between 100bps to 200bps  usually
> works well.  
>  
> John
>
>   
> >   Sorry for the amount of "ponders" in  this mail.  It is just my 2cents 
> >     
> worth 
>   
> >     that a higher frequency with less primary turns and a faster RSG would  
> >    overall reduce losses far more than anything  else.
> >     
>
> Chris
>
>
>
>
>
>
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