Re: Racing sparks

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

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.
>
>
>
>