RE: Racing sparks

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

Original poster: Thomas <tom-at-pwrcom-dot-com.au> 

Bart, I've already removed an inner turn, this solved the problem of primary
to secondary arcing, but I do not want to do it again, it was quite a chore.

JAVATC predicts that raising the secondary about 30mm will have the same
effect on coupling as flattening the primary, so I'm going to try that first
(new k=0.13).

I thought "Increasing the proximity between coils" would increase the
coupling? Did you mean decrease?

Thanks for your help,

Tom L.

Original poster: Bart Anderson <classi6-at-classictesla-dot-com>

Hi Tom,

0.17 is quite high on a 2-coil system. Increasing the proximity between
coils is my preference. Because you have a lock-in setup for the
secondary,
an alternative to increase the proximity between coils is to remove 1
turn
on the ID of the primary.

Take care,
Bart

Tesla list wrote:

 >Original poster: "Tom Luttrell" <tom-at-pwrcom-dot-com.au>
 >I rebuilt my blower spark gap,
 >http://www.webclot-dot-com//high_volt/images/toms_new_gap_2.JPG
 >
 >This has allowed for a considerable improvement in airflow and streamer

 >length. I'm now getting the occasional hit to the strike rail,
something
 >that did not ever happen with my previous gap.
 >
 >This new gap just fires at a setting of 8mm with only the NST
connected,
 >as opposed to about 5 to 6mm for my previous gap. I put this down to
the
 >sharper rim of the pipefittings as opposed to the flat brass rod face
of
 >my first gap (http://www.webclot-dot-com//high_volt/images/toms_gap2.jpg).
 >
 >Unfortunately it's too good. After about 5 to 10 seconds of operation I

 >start to see racing sparks on the secondary.
 >
 >My primary is an inverted cone (30°) and the coupling is probably a bit

 >tight (JAVATC calculates it to be 0.17).
 >
 >The way I see it I have the following options:
 >
 >1) reduce input power via my new yet to arrive variac
 >
 >2) reduce the spark gap (and hence firing voltage)
 >
 >3) cut down the primary supports so it becomes a flat pancake coil
 >
 >4) raise the secondary height.
 >
 >Options 1 and 2 have the advantage of being easy but would negate the
 >recent gain in streamer length.
 >
 >Options 3 and 4 would require some major rework, including
modifications
 >to the mechanical method by which a 1/4 turn twist of the secondary
locks
 >it in place.
 >
 >I'd be interested in reading any thoughts you may have on this matter.
 >
 >Tom.
 >
 >
 >
 >