Re: New Twin Transformerless Tesla Coil

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

Original poster: "Jolyon Vater Cox by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>

1)For L1/C1 would a transformed value of inpedance be permissible e.g. would
tapping L1 at some point between C1 and ground be OK?

2)For balance, would it be possible to measure ground current/ voltage from
the base of L1 to true ground and attempt to get a minimum value e.g could
the brightness of an LED or neon bulb connected between L1 base and ground
act as crude indication that balance has been obtained?

3) Following from 2) since network is a bridge and voltage from a position
midway between the resonator terminals (a and b) to ground is theoretically
zero at balance
doesn't the circuit have potential as a measuring bridge for capacitance and
inductance?

Incidentally, I am presently getting higher voltage from the capacitive
transformer (L2) than from the directly-coupled (L2') branch of my TC, the
output from L2' decreasing  as it is moved closer to the influence ring .
 Is it possible that the "better than expected" performance of the
capacitive transformer L2 is a result of a tightly-coupled influence ring
splitting C3 in half  (in which case  it  MIGHT be OK to connect the
influence ring surrounding L2' to ground instead of the base of L2' as
indicated) or are there just too many other variables to be considered?

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, October 02, 2002 3:52 AM
Subject: Re: New Twin Transformerless Tesla Coil


> Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>
>
> Tesla list wrote:
>
> > Original poster: "Jolyon Vater Cox by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>
> >
> > Today I modified my capacitive transformer mini-coil to operate in "twin
> > transformerless" mode by winding an identical secondary and connecting
it
> > directly to the influence ring of my first coil.
>
> This setup is quite difficuit to adjust at high-power. Even with an
> oscilloscope at low power the tuning is quite problematic. I was
> just experimenting with this using some capacitor and inductor decade
> boxes.
>
> > Performance was pretty rotten at first with only a protruding wire and
no
> > proper terminal (small purple arcs to grounded object only).A 1 2/8"
copper
> > disc was then  attached to the top of new secondary which, -judging from
> > increase in spark length to grounded object- caused an increase in
> voltage, no
> > doubt due to better tuning of the new secondary.
>
> Note that for proper balance both resonators must be identical, with
> identical top loads, and each must have an influence ring. And more,
> the capacitances shall be adjusted so the influence ring captures
> half of the capacitance from the resonators to ground.
>
> > There is voltage also between the terminals of the two secondaries as
> evidenced
> > by sparks between a wire attached one of the secondaries to the other.
> > and there is definate attraction of corona towards the space between the
two
> > terminals.
> > The sparks appear weak and corona-like however -due to the
high-impedance of
> > the parallel-network source, perhaps?
>
> The system is probably out of tune. Two identical resonators require
> the doubling of the primary capacitance, and the division by 2 of the
> primary inductance.
>
> > I also feel that the series-resonant input is very current-hungry with
two
> > resonators since each from the input side is a series-tuned circuit (ie.
low
> > impedance) and there are two of them  in parallel (lower impedance
still!)
> > Incidentally, L1 is same inductor (61.08 uH)
> > as used for the single capacitive transformer TC.
>
> Note that the two series resonant resonators don't drain their maximum
> current immediately, but just aftes some cycles. This is the normal
> energy transfer process. Anyway, the currents in L1 and C1 are much
> higher than the currents that go to the high-impedance resonators.
>
> > Am I reaching the limits of what is possible with an rectified
> ignition-coil HV
> > supply
> > powered off a 13.8V 5 Amp power unit?
>
> Not yet, I think.
>
> > I intend to build another ring same size as the first at the same height
> to go
> > around the base of the second secondary and to be connected to it. Could
> it be
> > that by slowing the voltage rise on the second resonator (by connecting
a
> ring
> > to intentionally increase C3) a better overall performance might result?
>
> I think so. But you must divide by 2 the impedance of the tank L1C1 to
> make it feed both resonators, otherwise the system will be out of tune.
>
> Antonio Carlos M. de Queiroz
>
>
>
>