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Re: Coil specs:
Chris,
Welcome to coiling, Chris!
Some quick suggestions:
1. Go to LDPE dielectric in your capacitor(s) to reduce losses.
Plexiglass is significantly lossier, and will reduce your performance.
2. Increase the tank capacitance to 0.02 uF to increase "bang size"
while matching the current delivery capability of the 12 kV 90 MA
source, and retune the system for best performance.
3. Go to a vacuum gap (either multiple parallel copper pipes or to Gary
Lau's style single-gap vacuum gap) to improve quenching performance.
4. Once you've done the above, consider going to 5" or 6" diameter
ducting to raise breakout voltage. You may also want to increase the
outer diameter of the toroid a bit. Also, try increasing the height of
the toroid above the secondary a bit to reduce toroid:strikerail hits.
Run the system in the dark, and back off if you begin to get abnormal
corona from the top of the secondary winding.
5. Eventually, you may need to use a longer secondary coil and use a
larger diameter wire to reduce secondary losses, and get higher standoff
voltage capability from your secondary. This will also help increase the
physical distance between the toroid and the strikerail, reducing
unwanted "hits".
Safe coilin' to you, Chris!
-- Bert --
Tesla List wrote:
>
> Original Poster: mel wise <mwise44-at-flash-dot-net>
>
> If anyone knows any areas of improvement on my coil, so I can get the
> max out of it, please let me know.
> SPECS:
> TRANSFORMER: 12KV-at-90ma modified neon
> CAPACITOR: .01 plate type (.1" plexiglass/aluminum flashing)
> SPARK GAP: cylinder type 7=3/4"x2" copper segments (total gap is .2")
> PRIMARY: 13 1/2 turns of #6 solid copper wire, turn to turn spacing is
> ~.375" (inside diameter is 10 1/2", outside diameter is 23 1/4")
> SECONDARY: 6.25" PVC form wound with 22 gauge wire w/ a winding length
> of 19", the lower most winding on the secondary sets 2" above the inner
> turn of the primary
> TOROID: I have two different ones. One is 4" dryer duct w/ a cross
> section of 14", the other is 4" dryer duct w/ a cross section of 20"
> (the 4x20 toroid has a bad tendency of hitting my strike rail alot)
> MISC PARTS: all hookups are with #6 stranded wire suing copper crimp
> connectors (total length of wire used in my tank circuit is 11 1/2', my
> movable tap consists of an alligator clip that is crimped and soldered
> to the tap wire, the ground off of my secondary is made of #6 stranded
> wire, universal earth ground (8ft ground rod)
> PERFORMANCE: The absolute maximum spark I have obtained under favorable
> weather conditions was 37" to ground (this only happened once). My usual
> maximum spark length is 34" to ground. My average spark length is
> 26-32". <ALL OF THESE SPARKS WERE W/ THE 4X14 toroid> I have used my
> 4x20 toroid only once and was pretty disapointed, It will only strike
> out about 12" before it curves under and hits the strike rail.
>
> See any room for improvement? I hope so.....
>
> Chris