RE: Instrumental TC tuning

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

Original poster: "Mudford, Chris" <chris.mudford-at-agresearch.co.nz> 

Hi Ed

You are correct in assuming a static gap (single gap of opposing
tungston carbide cutting tips that are equalateral triangles with 15 mm
side lengths and slightly rounded corners) which I set to ensure firing
with no tank circuit present.  I do run a small fan between the gap
which I will try turning off which should decrease the firing voltage.
What would you suggest for a gap setting if using a 6kV/30 NST?  Note
that my safety gaps on my filter were firing when I was setting my main
gap also (I do have 1200 ohms of resistance in my filter which the
safety gap is the first stage of).

Chris,

If your safety gaps are continuously firing with the coil in operation
and
they don't fire when connected only to the high voltage transformer,
then
you are experiencing 60 hz resonance in the primary circuit allowing the

primary voltage to go way above what would be normally expected.  Proper

setting of your main (static I expect) gap will fix this.  For a 15 kv
neon
sign transformer, I use .20" to .25" maximum.  Increasing your primary
capacitance value by about 50% will also help.

Ed Sonderman