Re: Another "My First Coil" story.
Subject: Re: Another "My First Coil" story.
Date: Sun, 08 Jun 1997 18:54:48 +1000
From: Phil Chalk <philoc-at-ozemail-dot-com.au>
To: Tesla List <tesla-at-pupman-dot-com>
Tesla List wrote:
> Hi Phil,
> To address one point:
> > From: Phil Chalk <philoc-at-ozemail-dot-com.au>
> > Organization: Secure_Logic
> > To: tesla-at-pupman-dot-com
> > With nothing on the top terminal bolt it tunes at around turn 6, and
> > throws several branching, violet, lightning-like sparks from the top of
> > the bolt into the air, of maximum length perhaps 9-10". (and LOTS of
> > NOISE !) It seems best with the secondary level or lower down inside the
> > primary, than above. Seems best with gap = roughly .1"
> > With a 6" copper sphere (toilet cistern float) on top, it tunes at about
> > turn 7, and throws the odd spark from the centre rib - sometimes. If I
> > put a pin on the sphere it throws sparks from there, but no longer -
> > perhaps shorter - than without the sphere. A roughly hemispherical spun
> > aluminium 'wok lid' about 12" diameter throws many short (<= 1") sparks
> > from the rim.
> The quick answer is that, assuming the coil is in tune (no time to
> check at the mo), there is not enough energy in the primary cap to
> get your output voltage to breakdown point. 6" should work at that
> power level though (360-odd watts). I reckon your cap energy should
> be around 0.5 Joules which must just about do it. Try altering
> coupling. Also, open up the gap a tad - e.g. 0.2" shouldn't overtax
> the transformer IMO. If the primary fires at a lower frequency than
> 2xfmains with the gap set wider, close it up again or the transfomer
> might say goodbye. Double the gap setting should just about quadruple
> your cap energy which would make all the difference.
> Let's know,
With gap about .2" (very roughly, by eye) & 15kV, 60mA, branches now
around 15" max from bolt, and about the same from the sphere. It is
better with wider gap, but the extra noise makes me worry for my neons.
(no safety gap, yet!) I have several improvements to try, but am away
from home a lot at the moment, so missing both Tesla coil & list. More