RE: Capacitor in series with transformer or S.G ? What is right?

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

Original poster: "Pete Komen by way of Terry Fritz <twftesla-at-qwest-dot-net>" <pkomen-at-zianet-dot-com>

Hello Harvey,

My comments interspersed within /*...*/.

Original poster: "harvey norris by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<harvich-at-yahoo-dot-com>


--- Tesla list <tesla-at-pupman-dot-com> wrote:
> Original poster: "Pete Komen by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <pkomen-at-zianet-dot-com>
>
> Harvey,
>
> On an ideal cap, the current leads the voltage by 90
> degrees.  Driven by an
> ideal AC source, at the peak voltage, no current
> flows.  We do not have
> ideal caps or AC sources.

I agree exactly, both inductors and capacitors
individually will be 90 degrees off set oppositely  in
their charging actions with respect to the input AC
voltage.

> For a resonant sized cap, the max voltage will be
> reached at the 60Hz peak,

Here we are going into confusion as to what is being
discussed. What you are indicating here seems to be
the actions of a capacitor being used for power factor
correction on the primary of the input high voltage
transformer. If you are instead referring to an actual
cap being used in the primary of the tesla tank
circuit, than I must disagree again.

/* No confusion, the cap charging at 60 Hz is the same one that discharges
at higher frequency in the TC tank.  It can be resonant at 60 Hz with the
XFMR secondary and resonant with the TC primary at higher frequency.  The TC
primary is ignored during charging because the inductance is very small
compared to the XFMR secondary. The XFMR secondary is ignored during cap
discharge and RF ringdown because it is high inductance and in parallel with
the spark gap. */

> but for an LTR cap the maximum voltage with a
> current-limited transformer
> occurs later in the cycle.  The LTR cap makes the
> transformer/cap circuit
> resonate at a lower frequency than 60Hz and thus the
> peak voltage comes
> later than the 60Hz peak.  The gap firing just
> kind-of resets the cycle
> position

Again here you DO seem to be referring to caps used in
the actual tesla tank circuit. Your statement
here,"The LTR cap makes the transformer/cap circuit
resonate at a lower frequency than 60Hz and thus the
peak voltage comeslater than the 60Hz peak."
   MY UNDERSTANDING OF LTR caps are that the values of
capacity to be used in the tank circuit are made
larger then resonant values needed for that used for
the primary TUNED TO THE SECONDARIES HIGH FREQ
RESONANCE.
/* It is the same cap.  LTR refers to Larger than resonant with the
secondary of the HV XFMR. */
  The caps used in the tank circuit have
nothing to do with 60 hz source freq, or schemes to
come into that resonance, which is exclusively dealt
with in power factor correction with manipulations
made prior to actual tank circuit, on primary side of
input transformer. If we are to compare the actual L
and C componenets in the tank circuit to how they ACT
AT 60 HZ, We find that the primary coil itself has
practically NO inductive reactance at 60 hz, and the
total sum of reactance present in the tank is then
primarily all capacitive reactance and not inductive,
AS regards to how that 60 hz input will allow
conduction, then we can conclude that it acts just as
stated, as a component of primarily all capacitive
reactance, where any cancellation of total reactance
made by primary is practically non existant.

> Charging the cap after gap firing just means that
> more current will flow
> through the transformer to charge the cap to the
> other peak.  The firing is
> 120 bps because when the gap fires somewhat after
> the 60Hz peak,

Again since we see that the currents in a capacitive
reactance will be 90 out of phase with the source
frequency 60 hz, then when the 60 hz voltage reaches
its peak, the current across the cap will be zero, and
its stored voltage than will be at maximium. If it
discharges across the gap at this point in time then
the arc then occurs in conjunction with with the
highest voltage point of the input 60 hz input, which
was the point of contention here where my thinking WAS
that this instead should be at zero volts 60 hz AC
input. So then I should conclude this thinking was
wrong and that THE GAP DOES FIRE AT MAX VOLTAGE PT OF
AC INPUT. Do I finally have the correct conception
here?
/* Yes, I believe that is the case.*/

 the cap
> cannot charge to a high enough voltage during the
> falling voltage part of
> the half cycle to cause the gap to fire again.
>
> In a series LC circuit at peak voltage, no current
> flows and the cap has all
> the energy.

Again this is not how I understand things. What you
are describing DOES OCCUR with either individual
capacitive or inductive reactance loads. However when
L and C are put in series, depending on how resonant
that LC combination is to the source frequency, there
will be some cancellation of reactance, and less
phasing difference between impressed voltage and
resultant current will occur, with the net result of
more conduction than either reactance alone would
allow.
/* I understand, in an ideal series LC circuit the impedance goes to zero at
resonance.*/

 At zero voltage, there is maximum
> current flow and the inductor
> has all the energy.  (while resonating anyhow).

Again this only describes the purely reactive
situation. The statement "while resonating
anyhow"shows why something doesnt sound right. SOURCE
FREQ RESONANCE IS NOT THE SAME THING AS A TESLA TANK
RESONANCE, BECAUSE THAT RESONANCE IS BASED ON A
FREQUENCY THOUSANDS OF TIMES HIGHER THAN THE SOURCE
FREQUENCY. /* See comments above. */
   Thus if we merely pick up a text book describing
resonance, that description cannot be automatically
applied to the tesla tank circuit, because that is not
what the texts are dealing with, they are dealing with
the subject of source frequency resonance. If one
reads these texts one will find that it is said that
the energy oscillates between inductor and capacitor.
For  source frequency resonance, because the current
is in phase with the impressed voltage, we know that
when the highest amperage occurs through the inductor,
the voltage is also at its highest point, and it is
/* On the contrary, when the current is highest, the voltage across the
inductor is zero and across the cap is zero.  The voltage across the
inductor leads the current by 90 degrees and the voltage across the cap
trails by 90 degrees.  This is why the impedance goes to zero at resonance.
The current is limited by resistance in the circuit. */
the amperage in the circuit that is enabling a
magnetic field of no inertia. If it had inertia it
would be responding in the conventional manner that
inertia acts with, where there is a delay of impressed
amperage vs impressed voltage, which is actually what
occurs with reactive loads,having a phase angle
between the cause and effect. Thus the effect has a
delayed effect in time, but at resonance this does not
occur, and the amperage and resultant magnetic field
instantaneously act as if the pressure is acting on a
subject of no inertia. Now in these texts it is also
noted that when the voltage goes to zero, the KINETIC
energy formerly expressed as a magnetic field then
gets expressed as POTENTIAL storage in the electric
field of the capacitor. HOWEVER THE INSTANTANEOUS
VOLTAGE ACROSS THE CAPACITOR IS THEN ZERO, EVEN THOUGH
IT CONTAINS A VOLTAGE (Q OF THE INDUCTOR)TIMES THE
SOURCE FREQUENCY VOLTAGE.
/* This confuses me.  C has a voltage and doesn't have any voltage??? */
 Thus this is how my own confusion evolved, by
comparing the actions of a tesla tank circuit
resonance to that of a source frequency resonance,
where in fact if a source frequency resonance
capacity were given an arc gap action, we then might
it expect to fire on the AC voltage zero crossing
point. /* Maybe so, but the source voltage is not across the whole LC
circuit, but the source is the inductance (L).  My mind bends... */ But
because a tesla tank circuit is actually
not source frequency resonance, and its actions should
be  most entirely as a capacitive reactance, where its
point of maximum voltage potential would be 90 off
that of the resonant model. So I hope it is then safe
to conclude that yes, the cap should be firing at the
peak of the AC voltage input.  HDN
/*  Yes, with certain caveats.  Imagine (I can't generate a picture right
now) the first half cycle of a sine wave plotted voltage versus time.  Add
to that a current output line that rises with the rise of the sine wave but
limits at 60ma.  Now the voltage on the LTR cap (and the NST output) will be
a straight line (more or less) starting at zero with the sine wave and again
intersecting the 60 Hz sine wave sometime after the peak.  That's my mind
picture of what's going on when charging the LTR cap with an NST.

The problem is this circuit is driven by the inductor (the XFMR), not an
outside source.  The voltage on the cap is opposite that on the XFMR
(Kirchoff's voltage law).  The voltage peak may not match the 60 Hz peak
because of the current limiting and the LTR cap.  It is reasonable to set an
RSG or TSG to fire at the 60 Hz peak and tune to best output.  For 120 bps
and LTR cap, I would bet that the best firing point is later than the 60 Hz
peak. If the cap charges during the falling part of the half cycle (after
the SG quenches), its charge adds to the current through the NST.  Seems to
me that this would play havoc with the current limiting of an NST (may be
why my 12/60 NST was blowing a 9A breaker) and tend to move the best firing
point closer to the 60 Hz peak.  Hmmm...  Should the NST be considered a
current source? */

> Remember that cap and transformers don't consume
> energy (except losses),
> they just store and release it.
>
> I hope this helps.
>
> Pete Komen


/* I have to think really hard about phasing, inductance, capacitance, and
resonance to make any sense at all of it.  Even when I'm not doing the math
behind it all.

Regards,
Pete Komen

Sorry for the length, but I couldn't see where to snip and still make sense.
*/