Re: bipolar coil design

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Esondrmn@xxxxxxx 

Lee,

I haven't built a bipolar coil Tesla coil, just seen pictures of 
them.  Your design as outlined below will need a capacitor of approximately 
.044 ufd with a primary of 7.5" id and 5 turns with .375" spacing.  You 
need to calculate the primary and capacitor by using only one half of the 
full secondary length for the calculations.  The pictures I have seen of 
these usually have small toroids at the ends like you propose then wires 
coming up and in with round discharge terminals on the ends of the wires, 
like hollow copper spheres maybe 5" in diameter.  This seems to be 
necessary to make sure the sparks only arc from one terminal to the other 
and not to the primary or secondary which would be more than handy.

Ed Sonderman
Original poster: Lee Kohlman <lwkksw@xxxxxxxxx>

I'm new to the list and have been collecting information and parts to build
a tesla coil.
I am planning to build a bipolar coil.

My current specs are looking like this:

Secondary- 20 Awg wound 56" on a 6.25" pvc form, approx 1700 turns
Primary- 6 turns .25" copper tube flat spiral 4.5" id, 8" od at center of
secondary
Hv Supply- 2x 15kV 60mA NST (parallel)
Cap- .03uF 45kV pulse capacitor
Topload- 2x 6" aluminum dryer duct 30" diameter toroid, 1 on each end 4"
from secondary windings.

Secondary frequency- 112.76kHz
Primary- 232.96 kHz

I used javatc to do the calculations.  If you want to see the complete
output let me know.

Any ideas?

Thanks,
Lee K.