Mini coil first light and coax voltage ratring

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Tom Luttrell" <tom-at-pwrcom-dot-com.au> 

For those coilers contemplating using coaxial cable with the screen 
stripped off for HV cable, the following document may be of some use, I 
can't remember where in the web I found it. The voltages are operational 
ratings, and so could probably take more:
http://www.webclot-dot-com/high_volt/coax.xls

I finally got around to finishing off my mini coil today as the server was 
down at work and I could do little else :-)

Pics are here:
http://www.webclot-dot-com/high_volt/images/Minicoil/FrameSet.htm

Parameters here:
http://www.webclot-dot-com/high_volt/images/Minicoil/2in_javatc.TXT


Notes:

1)	Counterpoise earth mat (black mesh on the floor) joins to an M8 bolt 
under the base, this is also connected to the building safety earth. So far 
no problems with any other equipment in the house.

2)	GN12 glands are not quite long enough to fit through the polycarbonate 
box sides (note the mains feed through has jumped off the fixing nut in pic 
DSCF0004

3)	Big coil shown for size comparison, parameters here: 
http://www.webclot-dot-com/high_volt/6in_javatc.TXT

4)	Getting about 43% of the 1.7*SQRT(PWR) equation, the big coil runs at 
about 70-80%, I blame losses due to the high operating fequency.

5)	I have another 6kV 30mA NST and am thinking of paralleling it up with 
the one (same rating) in the currently underpowered mini coil

6)	RF earth current meter (shown on controller box) needs work. When I 
first tested it on the big coil it seemed to work well, but that was due to 
the magnetic field around the primary inducing flux in the pick up CT 
toroidal core. Once it was placed at right angles to the field (and further 
away) my full-scale reading dropped to 2/10 of FS. I'm working on an active 
amp/precision rectifier/peak detector. Will let you know how it goes.

7)	Both coils need bigger top loads. The big coil top load is too big for 
the mini coil (not enough turns on primary to tap at resonance). Using a 
breakout bump I got 1cm streamers when tapped at the end of the primary.

8) The fan for the mini coil is probably under powered. It only makes a 
slight difference to max streamer length when runnung.

8)	In pic DSCF0013 the top load is about the size of the ship's (Aurora 
Australis ice breaker) helicopter deck, the sea in front is called f***ing 
huge.

Oh…and for a quick look at some big caps, here is a (large) pic of our new 
25kV 70kA 8/20µs surge generator, which will be used for testing lightning 
protection devices. I'll post more pics on the HV list when it's finished.
http://www.webclot-dot-com/high_volt/images/DSCF0008.JPG

Tom L.