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First Coil - No Sparks
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From: D.C. Cox [SMTP:DR.RESONANCE-at-next-wave-dot-net]
Sent: Wednesday, June 10, 1998 12:28 PM
To: Tesla List
Subject: Re: First Coil - No Sparks
to: DJ
Two possible problems -- first, you might not have enough primary turns to
resonate your secondary coil. Try some scrap wire like 12 AWG house wiring
and stick into slitted cardboard on edge to hold it. Try approx 30 turns.
Scrape a bare tap on each turn. See if you can find a tap that produces
resonance and then replace with your final copper tubing setup.
If you can't find any resonance with up to 30 turns, then I suspect the
type of caps you are using might be bad or have some type of internal
safety bleeder resistance. Replace with some different type of caps such
as micas, PE, etc., and try again.
With a 30 ma NST you only need 2 or 3 gaps. Set at .015 inches on each gap
for .045 inch total. Try this first and see if it runs with this setting.
If not, try the primary replacement, and if that doesn't work try replacing
the caps with some "borrowed" substitutes to see if they are the culprit.
DR.RESONANCE-at-next-wave-dot-net
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> From: Tesla List <tesla-at-pupman-dot-com>
> To: 'Tesla List' <tesla-at-pupman-dot-com>
> Subject: First Coil - No Sparks
> Date: Wednesday, June 10, 1998 12:00 AM
>
>
>
> ----------
> 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
>
>