[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: TC Spark Energy



Original poster: "David Thomson" <dave-at-volantis-dot-org> 

Hi Gary,

 > The force exerted by a spark on the atmosphere is like that exerted by a
 > firecracker.  It is not by any means a constant - the bigger the bang, the
 > louder the noise, and the higher the force, for both sparks and
 > firecrackers.  The atmosphere is certainly compressible.  If it were not,
 > propagation of sound waves could not occur.  Barometric pressure
 > is a variable.

Well, duh!  Of course you're right concerning the compressibility of the
atmosphere.  I don't know what I was thinking.

But as for the force, we need to see the force separate from the energy.
Force is equal to mass times acceleration.  The acceleration has to be
constant for the medium, the mass will vary by the number of electrons in
the streamer.  But it seems that adding more electrons causes the streamer
to become longer.  So it would seem that the force acting on the atmosphere
is constant per square unit of atmosphere.  It's kind of like blowing up a
long balloon.  When you blow more air the balloon gets longer but the force
against the balloon wall could remain the same (until the balloon is
completely full.)

A longer streamer would produce a louder noise than a shorter streamer.  But
the force against the atmosphere along the full length of the streamer could
remain the same, and probably does.  If the force against the atmosphere was
variable, then there would be no mechanism for the streamer to gain length.

 > Electricity is an incompressible fluid?  No more so than ghosts.

Electrons cannot be compressed, therefore the flow of electrons can be
viewed as an incompressible fluid.  And they are certainly real.

 >  >force_constant * secondary_frequency * spark length =
 > secondary_power_output
 >
 > Are you saying that a 1 foot long streamer from a 200KHz
 > secondary requires
 > twice the power or contains twice the energy as a 1 foot streamer from a
 > 100KHz secondary?  No.

Yes, but as I mentioned in a previous post, the energy is accumulated in the
capacitor and discharged as a single shot at the break rate of the spark
gap.  So with a Tesla coil with .011 newton force on the atmosphere, 100 bps
break rate, a 200kHz secondary, and a single one foot streamer has 6.706
watt output from the secondary during 1/100th second while a similar coil
with a 100kHz secondary has 3.353 watt output from the secondary.

This is merely saying that the lower the secondary frequency, the longer the
streamers will be.  Even Tesla noted that lower frequencies produced longer
streamers.

 > A tidy equation, but does not reflect the experience and reality of those
 > who have made these measurements.

Are you saying that secondary coils with the same output power but higher
frequency will produce longer streamers than similar coils with lower
frequency?

 >  >I'm glad I did this exercise.  It made me realize that any
 > given spark in a
 >  >Tesla coil has a frequency of 1/120 of the secondary resonance.
 >  I might be
 >  >able to exploit that in some way.
 >
 > Are you saying that the gap firing rate, bangs per second, must always be
 > 1/120th of the secondary frequency?  No, the two are completely
 > independent!  How else could a variable speed rotary gap work?

No, I wasn't saying that at all.  I was saying that for a coil which
specifically DOES have a 1/120th break rate each streamer does carry just
1/120th of the resonant frequency.  For any given coil, the streamer carries
only a fraction of the total secondary resonance.  That fraction is equal to
the break rate of the spark gap, whatever that break rate is.

Dave