First Coil - No Sparks

From:  Barton B. Anderson [SMTP:mopar-at-uswest-dot-net]
Sent:  Thursday, June 11, 1998 12:52 AM
To:  Tesla List
Subject:  Re: First Coil - No Sparks

My 2 cents:

I calculated your coils unloaded frequency at about 707khz and loaded (toroid)
at 328khz. I also calculated the system should tune at about 9 turns (~47uH).
The toroid is pretty large which may be making the system difficult to breakout.
The toroids capacitance calculated to 20.5pF. I couldn't help but notice you
tried at 4" and 8" above secondary. This is probably too high to start with. You
may want to first try to jump a point-to-point arc (add <nail - whatever> to
toroid and arc to RF ground rod) with the bottom of the toroid parallel with the
top winding to get started with.

Just some thoughts,

Tesla List wrote:

> ----------
> From:  djQuecke [SMTP:djQuecke-at-worldnet.att-dot-net]
> Sent:  Monday, June 08, 1998 8:07 PM
> To:  Tesla List
> Subject:  First Coil - No Sparks
> I just completed my first coil yesterday but I'm not getting any discharge.
> 4.3" x 21.625" secondary - 22awg - 10 coats laq before winding then 15 more
> coats.  Ground via 10' flat braided cable to 10' of #4 stranded to 8' ground
> rod.
> Started with slight overcouple.  Moved incrementally up to 1/4" above first
> primary turn (no affect).
> 19"x4" toroid - Foil tape over foil over dryer duct and pizza pans.  Tried
> 4" - 8" above final turn on secondary.
> 1/4" copper tube primary, spaced 1/4" 15 turns total - tried tap at several
> spot on turns 14 and 15.  15 degree rise. Just over an inch between first
> turn and secondary.
> 15kv 30ma NST
> NST protection -
>     A 500ohm/65w resistor from each NST lead
>     1000pf ceramic caps across resistors
>     3.5mh coil on each leg (one coil showed "minor" shorting so I removed
> both from circuit without affect)
> Safety gap - across NST (actually more like two gaps, one from each leg to
> ground)
> I set gaps so they just barely didn't fire with NST alone.  During runs, gap
> would go off almost non-stop, I adjusted so that it didn't go off, no change
> on output, readjusted so it goes off intermittently (once every 2 or 3
> seconds)
> Main gap - RQ static 6"x9x2" (8 gaps total) tested at 7 gaps in use)
> Caps - 4 Oil filled poly each rated around 5300pf, 7500v, wired 2 pair in
> series then the 2 pair are paralleled.  Value tested at 5240pf on a decent
> LC digital meter.
> Power controlled by 10a variac.
> There appears to be a great voltage increase if intensity of safety gap
> discharge is a correct indicator.  Main spark gap is firing and appears to
> be doing what I expected.
> All settings have resulted in zero output.  I had hope to be ballpark close
> and adjust from there but apparently, I'm not even on the field yet.
> Thoughts?
> Thanks,
> dj