Re: Coil Doesn't Fire

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

Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net> 

Hi Jim,

I'll intersperse comments and then take a guess at the end as to you
problem.

 > Original poster: JBarrett-at-trumbullcorp-dot-com
 >
 > Transformer:
 > 12,000 Volt 30 ma
 >
 > Caps
 > Panasonic ECW-H 0.0043uf +- 3% W.V. 1500 VP-P 2500 VDC with a 1 megaohm
 > bleeder resistor across each cap. 8 in series 12 parallel.

I think you want 10Mohm bleaders.  With 1Mohm the peak power will be 4.5
watts per resister (assuming no resonant rise).

Cres of you tranny is 6.6 nf .  Your Cp is 6.5 nf.  You may want to increase
Cp to 10.6 nf (static LTR value) to avoid resonant charging problems.


 >
 > Secondary
 > 21" of 22 guage wire on a 4 1/2 inch PVC Pipe

H/D = 4.7  OK

With 22 guage wire, you may be short on number of turns.  Choose the gauge
to get 1200 to 1500 turns.


 > Primary
 > 14 turns of 3/8 copper tubing mounted on 3/4 inch plastic risers set at 30
 > degrees. The inner radius is 5 1/2inches.

Radius or diameter?  If radius, you have 3.25 inch clearance between inner
turn and secondary.  More than needed and this will reduce coupling
coefficient that the 30 degree slope was used to increase.  Use JAVATC to
compute your coupling coefficient.  It might be easier to wind a flat
primary with 1.5 inch clearance.  3/8 copper tubing is overkill at these
power levels.  1/4 tubing will allow a more compact design and easily handle
the current levels.  I would wind 20 turns to allow greater choices of top
loads.


 > Torid
 > 22 inch major radius Of 4 inch flexible dryer duct mounted on aluminum
foil
 > covered 1/4 inch plywood.

I hope you mean 22 inch major diameter.  I used 15x4 toroid at that power
level.  22 inch would be interesting if you get breakout. If not try a thumb
tack on the outer extent of the toroid.

 > Spark Gap
 > Air cooled at 25 psi

Static will Cu pipes running parallel to each other will work fine (large
surface area for spark to spread out with helps cooling).  3 to 5 gaps with
air flow to blow out the ions and cool gap.


 >
 > Grounding
 > 2- 4 foot ground rods driven into ground and soaked with h2o.

Should be fine.

Ground secondary base and NST chassis to this ground.  Ground terry filter
and center terminal of safety gap to NST chassis.
 >
 > I believe my caps are the major source of the prolem however someone
 > pointed out that my transformer is a little small too.
 > Any other thoughts?

1. Fix you bleed resisters
2. Primary may be OK, just seems big. Make sure not overcoupled
3. Make sure your toroid is not too big and that your power level can allow
breakout.
4. Use JAVATC to check the tuning of your coil and make sure you have the
tuning range on your primary.
5. Make sure the safety gaps are set correctly
6. Tune your system at 30% voltage input (use variac)
7. Adjust main gap so safety fires only occasionally (not too often)