Re: OLTC update - Poor seconadry Q

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 9/1/02 10:22:53 AM Eastern Daylight Time, tesla-at-pupman-dot-com
writes:


>
> Really, if streamer formation depends on many cycles with the energy
> trapped in the secondary system, this may be a problem. I don't
> remember seing a study about this in this list. With Q=36 and 3300
> Ohms of series resistance, the equivalent parallel resistance is
> 36*3300 = 118800, and the streamer with 220 kOhms is really not
> contributing much for the energy drain.




Antonio, all,

I remember in my earlier coiling days, I built a tube coil and made
a large secondary 14" diameter x 26" long with three sizes
of wire, 22 awg, 24 awg and 28 awg, wound onto a sonotube
cardboard form, and coated with water-based poly.  What a
rotten coil !  The sparks were only 19" long, instead of the 24"  
I obtained when using a more normal sized secondary.  It didn't 
help that I used coax cable braid as the primary  :(   (!)  That
secondary got hot at the top !   I guess all the water from the
water-based poly went into the cardboard.  There may have
been other bad stuff in the cardboard sonotube also.  


>
> > Secondary loss, streamer impedance, and....  Is one of those areas that is
> > not terribly well understood.  Conventional coils seem to have just found
> > the sweet spot but this coil seems to have found a "bad" spot.  We'll
> > probably learn a lot before this is over :-))
>
> A question is: What is important for streamer formation? High Q
> secondary or a lot of energy available directly from the terminal?
> For sparks to ground, the later is the answer, but for streamers it's
> not clear.


And do successive beat transfers (poor quench) within a bang 
contribute much to the spark length, or is it more the initial energy
transfer to the secondary that is most important in establishing 
the spark length?  Perhaps the successive beats help to keep 
the channel ionized, and thus assist the next growth spurt in 
the next bang....  even if the successive beat transfers within a 
bang do not directly contribute to spark growth.  I realize Bert
H. has suggested that successive beats within a bang may
directly contribute to spark growth.

Another way of saying this is:  Does the spark length depend
more on the total power delivered to the streamer, or does the
manner and timing of the delivery matter more.  This would 
involves such aspects as; number of beat transfers in a bang, 
BPS, toroid energy storage, etc.  In other words the still-
unknown aspects of spark growth in air in Tesla coils.

John