Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>As mentioned my sec is 4.5" x 21.8085" wound with 24 awg. It's 895 turns (had to remove 5 turns due to a pin point breakout right at the top a few weeks ago when testing other primary configurations). My topload is 6.25" x 21". It's operating excellent right now using a static gap (1.25" x 3" copper tubing with .05" spacing between 6 tubes, 0.25" total). It's a vacuum gap. I've found the copper tubing to be superior to the solid brass which contradicts my statements in this area previously. The guys talking about thermal superiority using the copper tubes were correct. So out with the brass. Sure looked nice though.
Coupling is 0.129. The bottom sec winding and flat primary are even on the same plane. Free-air spark lengths are around 54" and my son mentioned a couple days ago that it's the smoothest running coil he's seen me build. This coil is also wound on a black pvc tube. Cap size is configured for 0.0188 uF and the inner primary is 1.48" from secondary (1/4" tubing, 1/4" spacing edge to edge tapped at 8.4 turns.
Take care, Bart Tesla list wrote:
Original poster: "D.C. Cox" <resonance@xxxxxxxxxx>On the 4 inch ID PVC coils we run #28 AWG 150 degree C. wire with good success. I've also run 30 AWG but this is only necessary if running a 9 kV 30 mA xmfr as opposed to a 12 kV 30 mA xmfr. With 60 mA available current I usually run a 6 inch ID PVC coilform for good output.John Freau's toroids work great on most all 30 mA coils. I usually run a 20 x 5 when going up to 60 mA and 6 inch dia. coilform.Dr. ResonanceIn a message dated 5/1/06 12:33:15 PM Eastern Daylight Time, tesla@xxxxxxxxxx writes:example, my little 4.5" coil is only 895 turns with 24 awg. D.C. would likely add two or three hundred more turns and use a smaller gauge wire. This may be a phenomenon for high L coils. I guess only D.C. could say if he's done the same testing with lower turn coils.