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RE: NEW COIL FIRING!


 > From: bhaley-at-shore-dot-net (Brendan Haley)

 BH> The question is: the winding stops about 4 inches from the  
 BH> top of the pipe. There is one sweeping wind from the end of 
 BH> the tight winding up to the top, where the discharge terminal 
 BH> is. Does this spread out the capacitance along this long wind, 
 BH> and away from the terminal. I have noticed that there is corona 
 BH> all along this wind, and the sparks seem to get stronger near 
 BH> the tight winding. 

 RQ> The only problems you are having is that: your discharger is
 RQ> mounted too high up off the top of the secondary winding; your
 RQ> discharger is too small in diameter; or both.

 BH> Not to harp on the subject, but why does the distance between the
 BH> winding and the discharger matter: i.e. what physical phenomenon is
 BH> occurring. Is it extra resistance from the wire, or capacitance? 
 BH> Normally I would envision the points as electrically equivalent, 
 BH> regardless of this length. I know I am wrong in assumming this,  
 BH> and I am curious as to why.

 BH> Also,  while I'm asking, what purpose does the discharger serve?  
 BH> A coil still produces the wireless power transmission without the
 BH> capacitive hat. 

Ok, ok, ok, I give up already! First of all the toriod is the classic,
and most effective, electrostatic shield. Tesla was the first person to
use this particular shape for this purpose during in the course of his 
work in Colorado Springs. The toriod works much better than a sphere.
You never bothered to really tell us anything about your coil system,
or the type discharger you are using. You should be using a toriod
discharger, but it sounds more like you are using a sphere; it may
even be a sphere that is smaller in diameter than the secondary coil
winding itself (I am guessing due to the complete lack of supplied in-
formation). Regardless, since the toroid is perferred, and more people 
nowadays are using them, I am going to go on as if we are talking 
specificly about toriods. If that does not apply, then please provide 
more information next time. We love to hear details about people's 
coils, dischargers, capacitors, etc., so you would find it hard to 
bore us with detailed descriptions.

Anyway as I was saying, one of the most important characteristics of
the discharger is to shield the top windings of the Tesla coil to
prevent arcing and corona off the top turns of the coil. In order for
a discharger to provide good electostatic shielding and protection it 
must be; physically close to the top of the coil, and larger in dia-
meter than windings the discharger is protecting. This has nothing
to do with capacity, resistance, or inductance. This is a character-
istic of ELECTROSTATIC SHIELDING.

One of the unfortunate things about many modern coilers is their belief 
that the ONLY function of the toriod is to shield the top turns of the 
coil from corona and spark breakout, which is somewhat the opposite of 
your misunderstanding. For yet another major advantage of the toriod 
discharger in Tesla coil systems is that the toriod introduces ISO-
TROPIC CAPACITY to the top of the secondary coil.

ISOTROPIC CAPACITY lowers the frequency of the coil and increases the
base current. It aids in balancing the coil out into a more functional
"RLC circuit" as opposed to just a huge, open ended, inductance. This 
has the effect of allowing greater VSWRs (Voltage Standing Wave Ratio) 
in the coil. The toriod is therefore a key component in achieving truly 
phenomenal performance. It is a experimental fact that toriods can be 
enlarged to a very great degree to achieve higher and higher potentials. 
The upper limit of this gain is the ability of the coiler to pump more 
power into the secondary and the ability of the coil to withstand the 
electrical stress without breaking down.

The isotropic capacity of a discharger varies with it's distance from
ground and other conductors. But this variation is not a significant
factor to the problem of arcing and corona from the top turns of the
secondary, which is simply a problem of electrostatic shielding.

As to your last comment that "A coil still produces the wireless 
power transmission without the capacitive hat." I would agree, but 
any coil without a proper discharger or capacitive hat will be 
terribly inefficient, and this would be especially true if the coil
was designed or used to transmit power.

 BH> And finally, could you explain the role of the spark gap. I've 
 BH> seen it described as providing "harmonically rich" current in 
 BH> order to cause the tank circuit to oscillate. That is both 
 BH> nebulous and suspicious sounding to me. Is the spark gap width 
 BH> important in the tuning, or is it fine merely sparking?

Well first off lets make a distinction which points toward the true
function of the gap in the Tesla Tank circuit; Tesla referred to the 
gap more often as a "break" than as a "spark gap". Secondly, the 
common air gap is really more of an "arc" gap than a "spark" gap,
given that the current that passes through the gap when it is firing
produces a healthy plasma channel. Regardless, the spark gap is 
plain and simply a high voltage switch that allows the capacitor 
to charge from the power supply, and then to discharge in a high 
current pulse. The performance of the gap is what allows the Tesla 
Tank circuit to develop peak powers in the kilowatts, even megawatts, 
from common AC supply mains.

Think about that gap as like a "brain" that controls the operation
of the tank circuit. It allows a maximum voltage to develop on the 
capacitor when it is open, then upon closing allows the capacitor
to suddenly discharge with a high current pulse thru the Tesla Tank
circuit. Once the energy of the pulse drops, the gap opens, which 
allows the capacitor to recharge for the next cycle. It is switching
the capacitor back and forth from a "slow" charging mode where it is
supplied by the step up xfmr, to an oscillating mode where it is 
suppling high peak powers into the rapidly oscillating, high current,
resonant Tesla Tank Circuit. By closing the gap down you allow that 
gap to fire at a lower voltage, and you thereby reduce the peak power 
of the pulse that develops. This allows you to control the power level 
of operation and the amount of strain put on the capacitor. Another 
factor to consider is the duration or "dwell" time of the arc in the 
gap. The quicker the gap functions (switches open and close) the greater 
the peak power developed, the more strain is placed on the capacitor
dielectric.

 BH> Sorry to ask so many questions, but now that I finally got the 
 BH> thing working, somewhat, I am filled with curiosity. I was hesitant 
 BH> to ask these questions until I had a working coil, and now I feel 
 BH> more involved. So, any suggestions that would help me on my quest 
 BH> to becoming a better coil builder are greatly appreciated.

Well as this has grown in the last hour so into several pages I would
think that I have left you with some food for thought. I would really
appreciate it if you would take some time and let us have a short
paper with detailed specifications about your coil system.

 BH> P.S.  Thanks for the congratulations

Your very welcome! You earned it.

Richard Quick

... If all else fails... Throw another megavolt across it!      
___ Blue Wave/QWK v2.12