Re: [TCML] Spark gap comparisons

[FutureT@xxxxxxx]

In a message dated 2/23/2008 10:46:18 P.M. US Eastern Standard Time,  
bartb@xxxxxxxxxxxxxxxx writes:

>Hi John,

>I think a rotary or triggered gap may or "may  not" outperform a static 
>gap if all at 120 bps and because one can't  assume all static gaps are 
>the same (if they do, their naive).  

Bart,
 
I agree with the above because you left out the stipulation that I  included
that the coil in question must have an LTR cap, and be powered by  an
NST.  I agree that there are many things that we can't yet  conclude
about coil operation, yet there are things that we can conclude at  least
on a practical basis.  For example if I'm speaking to a newbie  coiler
who has no familiarity with coil behavior, he might wonder when he
can get a stronger spark using a 120 bps  rotary or if he can  get
an equally strong spark using a static gap.  If he has an NST,  LTR
system, I'd feel pretty confident telling him that he'd get longer  sparks
by switching over to a 120 bps rotary gap system.  In fact this  has
happened many times on this list.  I consider this to be  practical
information that a newbie coiler can use and benefit from right  now,
"before" spark gap physics is better understood.  Certainly all  static
gaps are not the same, but I'm suggesting that even the best ones
cannot outperform the rotary in the situation I describe.  I  consider
this to be a rule of thumb of coiling.  I suppose it's possible  that
there might be some rare "outlier" type situation where what I'm
saying might not be true, but most newbies probably want to know
what works in nearly all cases.  Much would be depend on the  type
of newbie.  If a particular newbie wishes to begin their  coiling
experience by learning the most intricate details of arc-dynamics,
and the physics of coiling, then they might approach things in a
certain way.  Others want practical information about coiling.
Many of the newbie questions that I see on this list are of that
type.  And that is the type of question which I was responding  to
with my comments.  If I can offer rules of thumb which tend to
work well, that's something that can benefit a newbie.  
I can understand your cautious view of not
wanting to jump to any conclusions about the behavior of coils
before things are fully understood.  I also think it's important  to
address what type of behavior a newbie might see in a particular
design of coil.  For this purpose I divide coils in the various  
"styles".  For example there's the NST, LTR coil which has
certain characteristics, then there's the NST, STR coil which
has other characteristics.  Then there's the ballasted pig  coil
which has still different characteristics.  If the newbie can  get
a grip on the expected behaviors of these various types of coils,
then he's ahead of the game at least as a starting point.  As  he
progresses in his coiling over time, he may or may not decide to
study the underlying physics, or subtleties of coil and gap 
behavior, etc.  The ideas I'm offering offer a starting point  for
understanding for the newbie as he's approaching coil design
questions.  
 
 
>Maximum spark output as a 
>comparative value can be good or  bad depending on many variables. But 
>given the data at the time of  measurement, usually a single conclusion 
>would be made (what you see  is what you get).
 
Again, most newbies when they begin coiling, are looking for  maximum
spark length from their coils for a given input power.  I'd say at  least 90%
of the newbie questions on this list attest to that.  Other newbies  want
maximum spark length regardless of input power !

>I agree that more of "us" should join in and do the  comparisons that you 
>have done (as you know, you are in high regard  with me in this respect). 
>But even though that is true, I still have  doubts on conclusions on some 
>things (not to be disagreeable, but  simply attempting to understand the 
>conclusions with the tests at  hand). I guess it comes down to the more I 
>learn, the more I don't  take everything at face value and give a little 
>more attention to  statements or conclusions.


You're approaching the issues as a true scientist and  researcher.
I have that side of my personality also, and hold it in high  regard.
I think there's also a place in coiling for rules of thumb, or  general 
guidelines
for what a coiler can expect from a particular coil  configuration. 


>I'm uncertain on many past gap experiments of comparison. I  think all 
>test are certainly worthwhile and tell us something, but I'm  not sure we 
>have actually determined well what it is the tests have  shown us. More 
>work is certainly needed in this area as you have  stated in just about 
>every post on the subject. I think your exactly  right about that.
 
I agree that many past gap experiments were poorly done and  resulted
in wrong conclusions.  Some of my early experiments fall into  that
category I later realized.  Yes, more work is needed.
 
Cheers,
John
>
>Best  Regards,
>Bart





FutureT@xxxxxxx wrote:
>  Bart,
>  
> I think that in probably all cases an NST  powered  LTR coil under
> 2 or 3kW will give longer sparks using a  120 bps rotary or a  
> 120 bps triggered gap than
> using a  static gap.  If the coil has a smaller (STR) cap,  then
> it  may do just as well using the static gap as with a  rotary,
>  because it's no longer necessary to fire at the peak  voltage for
>  best results.  Also such a coil may need an ASRG to  find
>  the sweet spot.  In coils that have non-shunted   transformers
> the picture becomes more complex because the degree  of
> ballasting effects the input power, etc, and can enable   the
> coil to perform at various break-rates, etc.  Regarding   how
> the gap is being evaluated, I'm looking simply at max   spark
> output.  If the gap heats up after awhile and the  sparks  shrink,
> then it's obvious more cooling is needed, or a  re-design, etc.  
> Certainly a high powered coil will need a more  robust spark
> gap, etc.  Many of these things are just common  sense
> issues.  I consider the comparisons to be valid as long  as
> the sorts of things I mention are considered.  It would  be
> good to see more folks doing such comparisons however.   
>  
> John
>
>    








**************Ideas to please picky eaters. Watch video on AOL Living.      
(http://living.aol.com/video/how-to-please-your-picky-eater/rachel-campos-duffy/
2050827?NCID=aolcmp00300000002598)
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla