RE: TC Secondary Currents - was ( Experimental Help - Terry?)

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

Original poster: "John H. Couture by way of Terry Fritz <twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>


Antonio -

What I am trying to do is determine how to use the measured secondary
current to find the TC output of the secondary coil. With this information I
could then find the overall TC efficiency by

    Overall efficiency = TC output/TC input

When I measure the secondary current I get as you say a combination of
transient currents. How should these currents be used to find the TC output
energy. Other measurements are needed but how should they be made? The input
energy can easily be found.

John Couture

---------------------------------


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Sunday, March 03, 2002 11:40 AM
To: tesla-at-pupman-dot-com
Subject: Re: TC Secondary Currents - was ( Experimental Help - Terry?)


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: "John H. Couture by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>
>
> To explain the problem further, I regard the ohmic currents as
> (a+j0)(streamers)and the reactive currents as (0+jb)(cap charging). When I
> am getting streamers the current is (a+jb). Or is it (a+jo) and (0+jb) at
> different times of the cycle? With utility currents I can separate the two
> currents easily to find the power factor or I can find the power factor to
> separate the two currents. With Tesla coils I have not been able to do
this
> because I have not determined how to measure the high secondary voltage
with
> the true phase relations with the (a+j0) or (0+jb) currents.

Phasor analysis is only applicable to steady-state single-frequency
sinusoidal signals.

A Tesla coil operates with transients, that are not sinusoids, and
contain more than one frequency, even in the idealized lossless case.
It is possible to use phasors to compute approximate relations between
voltage and current, and even possible to calculate these relations
exactly in a lossless system before breakout, considering two
frequencies
and adding the results in the time domain, but this would not be very
useful, since you would have to calculate first the voltages or the
currents by some other method, as there is no AC source in the
system during the energy transfer.

> As I recall Terry was able to create scope curves showing both the current
> and voltage, but the phase difference could not be used to find the
separate
> currents. I may be wrong in this assumption. It was also my understanding
> that the displacement current could not be determined.

This is because the waveforms are not sinusoids.
Displacement currents are just an idealization. If you change the
voltage
in one plate of a capacitor, you induce a voltage in the other plate.
The same effect can be obtained if you connect the plates by a wire
where a "displacement current" passes, and ignore the electrostatic
coupling between the plates. Curiously, a displacement current works
really as a real current. It even has a magnetic field around it.

Antonio Carlos M. de Queiroz