Sudden Jump in NST Current

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

Original poster: "David Kyle by way of Terry Fritz <twftesla-at-qwest-dot-net>" <dave-at-kyleusa-dot-com>


Coil Specs:

20 Amp Variac power controller

3 x 15KV at 30ma Transco transformers for a total of 15KV at 90ma

210uf PFC capacitor

Standard Terry RC neon protection circuit (less MOVs)

SRSG using .1 inch Thoriated Tungsten electrodes with a static safety gap in
parallel

John s SRSG LC phase circuit 

.03 uf at 70 KV Maxwell capacitor bank 

Primary - 14 turns .25 copper tubing currently tapped at turn 10 

Secondary 6.25 inch PVC with 36 inches of #22 wire 

24 inch spun aluminum toroid

 

First let me express my thanks to the participants of this list for the awesome
assistance that has enabled me to exceed my goal of achieving 36 inch arcs.
After some serious tuning I have observed greater than 36 inch streamers and I
am sure there is more to be had. But I am seeing significant current
consumption that I am unable to explain.

 

I did my initial current tests with a Jacobs s ladder and saw a max of about 10
Amps with the PFC caps. When tuning the coil I find that as I bring the voltage
up I first get multiple dancing 18 inch streamers with a very raspy sound from
the SRSG. Current draw appears to be in the range of 10 to 15 Amps. Then as the
input voltage reaches about 100 volts a dramatic transformation takes place.
The sound becomes a singing 60Hz and a single very strong streamer starts to
reach out and slowly circle the toroid. The combination of the sound and the
bright streamer reaching out over 36 inches is impressive if not a bit
daunting. But a look at the meter shows the current jumping to greater than 30
amps and after a minute or two the 20 amp fuse in the Variac blows. I also
noted the NST protection circuit resisters get very warm suggesting a
significant jump in NST output.

 

Might this be the NST going into some kind of saturation mode and if so am I
running into trouble?

 

Dave

 

=========================================
Dave Kyle
Austin, TX USA
Email: dave-at-kyleusa-dot-com