futuret@xxxxxxx wrote:
Dave,I think it should be possible to get sparks longer than the secondary. To do this long arms would have to reach out high and wide above the horizontal secondary,from each end. Perhaps toroids would be needed on top of the arms to increase the spark lengths. Breakout points may be needed also. It would become a monstrous beast perhaps.
I once made a bi-polar coil that produced sparks longer than the secondary. Actually, there were three coils: The bipolar secondary, and an additional vertical coil on each end of the bipolar coil. The secondary coil was inside a lucite tube, and the additional coils were connected to the secondary by copper tubing. The primary coupling was fairly tight and sparks would play all over the lucite if the additional coils weren't breaking out at their breakout points.
The additional coils were mounted to the tops of 8" cardboard concrete-casting forms. I could move them as far away from the primary/secondary as I wanted to.
The only problem was that the additional coils required very large toroids, otherwise I would get primary/secondary spark-over from the tight coupling. And by the time I added in the additional coils and the large toroids, the operating frequency was so low that I couldn't find a really good tuning point even with a 30-turn helical primary. I should probably have built it much smaller.
The secondary was 4" x 4', wound with #28 and the additional coils were 6" x 22", wound with #24. The toroids were aluminum ducting, 8" x 24". I did manage to get arcs across the toroids that were longer than the 4' secondary. If I was to do this again, I would halve the dimensions of everything to get the apparatus into a decent operating frequency range.
Oh, and the secondary was continuously wound all in one direction. Dan K. _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla