RE: Request for help with air core transformer/power transfer system

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Harvey Norris <harvich@xxxxxxxxx>


--- Tesla list <tesla@xxxxxxxxxx> wrote:
  > -----Original Message-----
>  > From: Tesla list [mailto:tesla@xxxxxxxxxx]
>  > Sent: Monday, December 06, 2004 8:01 PM
>  > To: tesla@xxxxxxxxxx
>  > Subject: OT: Request for help with air core
> transformer/power
>  > transfer system
>  >
>  >
>  > Original poster: David Speck
> <dave@xxxxxxxxxxxxxxxx>
>  >
>  > List,
>  > I know this isn't directly TC related, but I
> hoped someone with more
>  > transformer theory experience that I have might
> lend a hand,
>  > with Terry's
>  > indulgence.  Please feel free to respond
> privately.
>  >
>  > ->Sound enough like electricity transmission
> without wires ;o))  But
>  > respond direct if not really related to Tesla
> coils) - T. <-
>  >
>  > I'd like to transmit about 6 volts AC at 60 Hz
> and 250 mA
>  > through a glass
>  > plate about 1/4" thick without drilling a hole in
> the glass,
>  > and without
>  > making any really esoteric circuitry like a high
> frequency drive
>  > circuit.
I achieve almost perfect coupling with spirals using
wide margin width wire so that the spirals encompass
internal capacity. By perfect coupling, this implies a
reduction of impedance to the source; when the
recieving instrument is in proximity. As such the real
question is simple, place a set of spirals between a
glass plate, and record the inductance of the source,
where both the open circuit and closed circiut
configurations of the secondary are noted. If the
impedance of the source, neglecting resistive losses
which are ordinarily insignificant in my case of coil
transmissions: if that impedance doubles then you have
perfect mutual coupling with identical L sets of
spirals. At a 6 VAC @ 60 HZ measurement, the
proposition shows that such a "source frequency"
inductance change measurement between spiral sets is
practically impossible, and typically such a
determination of mutual inductance by classic methods
states that the difference between those two reactive
states dictates the mutual induction between the
systems. The situation you are here describing is
easily possible by several considerations. The first
loophole beomes the fact that L1 and L2 as proximity
reactance measurements in fact can have little to do
with those same measurements made when each L quantity
is given a C quantity to resonate at the source
frequency resonance. In other words what looks like
almost independent magnetic action of two components
when measured in the reactive state, can exhibit far
more mutual inductance states when each L is given a C
value to resonate at the source frequency that now
delivers a whole new set of values is taken with
current delivery measurements on both input and output
comparisons of secondary open and closed situations.
As such the action of Of L2C2 as secondary can
influence the choice of the C1 value on the tuned
segment on the primary L1C1, whose C1 value is first
tuned to the  reaction proximity of condition L2C2
circuit/ In the case of mutual inductance at resonance
however it is only mutual when the components share
flux change. As such a square multiturn coil can
induce more flux change on a adjacent spiral, then the
reverse situation will allow. and because of this, the
normal determination of mutual induction effects is
invalidated by comparing the unity to opposition
measurements in the reactive states, which is the
normal parameter noted as L1L2 interactions, which can
be signicantly greater or different between each other
when paired as L1C1/L2C2 interactions. To secure a
high inductance L1C1 primary at 60 hz would be a great
problem, but probably not nearly as bad as the problem
involved wiith matching the C2 value to the low
inductance spiral of the receiving instrument.  The
key to considering the validity of air core inductive
systems at source frequency is the consideration that
AC alternators can easily deliver frequencies in the
500 hz range or beyond, and then the sensible pairings
of L1C1/L2C2 values can be made. In this described
situation of paired spirals between glass, @ 480 hz
with resonant spirals matched to the frequency
transmission of the alternator, power transmission
between the components would only be reduced according
to the flux leakage afforded by the glass, maybe a 80%
power loss, according to my guess. ()

 An eight fold increase of frequency to 480 hz makes
the inductive reactance go up eight times by X(L)= 2
pi*F*L, but the capacitive reactance X(C)= 1/[2pi*F*C]
means the inverse C value for matching reactance goes
down 64 fold in comparison to original demands at 60
hz: thus effectively enabling sensibly tuned L1C1/L2C2
spiral arrangements. In a 0ne inch layer of of 9 inch
diameter, 2 inch ID spiral winds comprising four
layered spiral winds of some 120 winds, the value of
matching capacity of the 2.3 mh spirals was shown to
be ~7 ohms, some 44 uf of capacity. Such adjacent
spiral groups as adjacent sets were shown to have a
high mutual inductance, MERELY ON THE REACTIVE
READINGS ALONE! What this means is that according to
starting understandings the inductive reactance is
first measured at 7 ohms, but because the spirals
share almost complete coupling of flux change, the
adjacent presensce of the shorted secondary L2,
decreases the impedance measurement of L1 to be almost
half that of the former measurement, thus showing good
coupling in the reactive state. Thus based on the
readings of the new reactive state, each capacity of
the tuned L1C1/L2C2 combination would be also doubled
on first approximation, to comparative readings made
in isolation. That would be how things are tuned from
the data of interactions obtained from the reactive
state of mutual induction, which also predicts the
correct capacities to be used in the resonance,
however in some cases of resonance the mutual
inductance measured in the reactive state is different
from its resonant case. Thus a second approximation of
tuned L1C1/L2C2 values is in order when the mutual
cou-pling is not as great, to see whether the change
in both C values simultaneously to a higher value
according to an increased lenz law effect at resonance
comes into play.

Power transmission is easily possible through glass at
alternator frequencies, provided a correct match of LC
spirals is negotiated.
Sincerely HDN