Re: joules confusion sort of

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Harvey Norris <harvich-at-yahoo-dot-com> 


--- Tesla list <tesla-at-pupman-dot-com> wrote:
 > Original poster: "Gerry Reynolds"
 > <gerryreynolds-at-earthlink-dot-net>
 >
 > Hi Luke,
 >
 > The true enery per bang will be 1/2 * CV^2.  The
 > 900/120 estimate assumes a
 > power factor of 1.0 and a Cp that results in 120
 > BPS.
Isnt Cp irrevelant to the BPS rate, and any small
capacity will naturally exibit a 120 BPS rate by the
proper gap spacing?

  The 15KV * 60ma is
 > the VA rating of the NST and calling it a 900 watt
 > transformer is probably a
 > misnomer.  The actual power from the NST will be
 > power = VA * power factor.
 > The power factor (and I'm not talking about PF
 > correction) is dependent on
 > the type of spark gap (static vs sync rotary).  I
 > think one needs to think
 > (in the context of static gaps) of a PF of ~0.5.
 > Static gaps can not take
 > advantage of the energy stored in the inductance of
 > the NST (aka inductive
 > kick) like SRSG's can.
Is this a syncronious rotor arc gap, I am unfamiliar
with SRSG as a term.

   Note that 1.6 * Cres with a
 > static gap gives about
 > 120 BPS.
I am still at a loss as to how the capacity correlates
to the BPS rate?

With a SRSG at 120 BPS (called pps as in
 > presentations per secend)
 > and timed right, a Cp of 3.2 * Cres can be almost
 > fully charged (hence
 > approximately 900 watts are can be processed.
 >
 > Gerry R
Isnt this a more complicated issue where we need to
find the RC time constant of the tank capacity value
to know if the cap can be fully charged in one half of
the AC input voltage signal?
 >
 >  > Original poster: "Luke" <Bluu-at-cox-dot-net>
 >  >
 >  > When talking about a 900 watt NST (15KV 60mA)
 > operating into a 120BPS
 >  > static gap the joules has been said to be 7.5 per
 > bang.
 >  > 900 / 120 = 7.5
 >  > this makes sense to me since the 900 joules in
 > one second will be
 > displaced
 >  > over 120 pulses.
 >  >
 >  > but the cap size seems to dictate other wise.
 >  > A cap with a value of 0.016 mfd and a peak charge
 > voltage of 21.2KV would
 >  > only have 3.6 joules
 >  > 0.000000016 * 0.5 * 21200^2 = 3.59552
3.6 joules disharging 120 times per second would only
be 432 joules per second. I think this was touched on
before with varying loads placed on an NST, and
finding that the maximum energy transfer is one half
the stated  reactive VA value.
 >  > I am assuming the static gap would be running at
 > 120bps for this.
 >  >
 >  > Even if a rotary gap were used and a cap size of
 > 0.028 mfd were used the
 >  > joules would be 6.29
 >  > That isn't even up to the 7.5 joules used by some
 > for calculation.  Lets
 >  > not go there on the rotary for the answers yet.
 > J don't want to confuse
 >  > myself.  Only pointing out that that doesn't
 > equate either.
 >  >
 >  > Is there something I am missing?
 >  > Why do some use the 7.5 joules when the cap size
 > would not let it store
 >  > that much energy any way?
In series resonance of high q coils initially each
reactive current measured separately is equal at the
source frequency. The energy transfer in joules per
second in that condition is similar to what you are
saying here, that is the amount of storage that the
caps will give at the provided voltage input. However
when we place those reactances in series, the energy
transfer rate will have increased Q fold. The ability
of those caps to have increased their energy transfer
rate occurs being now they are subject to an internal
voltage rise that is Q times the input voltage. If we
use Cres as a tank value, if the gap does not fire,
the next half cycle will begin a higher voltage
deposition on the caps. I do not know if using a Cres
value would produce resonant voltage rise with a 120
BPS system that dumps the stored charge every charging
cycle.  If it did the higher joules per second
estimate would be justified. It might be practical to
make a scoping of a series resonant voltage rise, to
see how many cycles it takes to come to its complete
voltage rise. I will need zener diodes to try that.
 >  > Any insights on this?
 >  >
 >  > Luke Galyan
 >  > Bluu-at-cox-dot-net
 >  >
 >  >
 >  >