RE: Latest coil
The racing sparks occurred for as long as I ran it, which wasn't too long
since I was afraid I'd damage the secondary (and did). My secondary is
4.25" dia x 23" long. I think I may follow the advice offered by John Freau
and build a larger (6 x 28) secondary. In addition to being longer, this
will also allow me to use more primary turns with a higher surge impedance,
and lowering the frequency is good in that it lowers losses.
For both of us, the racing sparks began when we used higher valued caps,
which not coincidentally required us to use fewer primary turns. This had
two unintended consequences. The coupling is increased with fewer turns,
and the transformer turns-ratio is increased. I hope that a larger
secondary, leading to more primary turns, will fix this.
Regards, Gary Lau
Waltham, MA USA
>Original Poster: Don Allen <dona-at-amigo-dot-net>
>At 01:00 PM 09/05/1999 -0600, Tesla List wrote:
>Hi Gary, all,
>I've been using just one .01 mfd cap on my coil for a while
>doing experiments. I added the second one into the circuit
>last night to get .02 mfd and got racing sparks right off the bat.
>Actually, the sparks want to travel straight down to the base
>of the secondary.
>Since I last ran both of the caps together, I have adjusted the
>secondary coupling. It is fine with one cap but with both I think
>it's just too much. With two caps, there's a lot more corona
>coming off the topload
>Do the racing sparks happen the entire run, or do you
>notice it at a few seconds into power-up? Mine were the
>entire (brief) run.