Re: Who needs a quenching gap ?

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

Original poster: "Marco Denicolai by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Marco.Denicolai-at-tellabs.fi>






"Tesla list" <tesla-at-pupman-dot-com> on 12.12.2000 04:21:02

To:   tesla-at-pupman-dot-com
cc:    (bcc: Marco Denicolai/MARTIS)
Subject:  K magic values (was Re: Who needs a quenching gap ?)



Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <acmq-at-compuland-dot-com.br>

>> 2. Looking at the waveform, how you can "see" when the total energy
>> transfer has
>> completed?
>
>You have to plot the primary and secondary voltage and current. The
>energy
>transfer is total at a point where only the secondary voltage is not
>zero.

>> 3. How it can be that this transfer completes at the second or Nth envelope
>> notch? I always though that at each notch ALL the energy has gone once
to the
>> secondary and back to the primary, partly dissipated in losses: how's that?
>
>The envelope notches in the primary (that reduce the primary voltage
>to zero) don't necessarily coincide with the zero crossings of the
>primary and secondary currents. If the coincidence is imperfect, the
>energy in the system don't go all to the secondary capacitance
>(terminal included), because when the secondary voltage is maximum
>this occurs out of a primary notch, and some energy is still present
>in the primary, and/or when the primary voltage is zero the primary
>current and/or the secondary current isn't null.
>The perfect coincidence of zeros in all currents and the primary
>voltage only occurs with one of those "magic" coupling coefficients,
>and exact tuning.
>
>Antonio Carlos M. de Queiroz

Hi Antonio,

Thanks for your explanation. I have been plotting (simulating) now also primary
and secondary currents and understand a little bit more what you mean. But:

1. primary current and voltage are always 90 degrees shifted (of course):
so how
can you get all zeroes besides secondary voltage? I mean, should I look for a
zero in both currents only?

2. therefore the total energy transfer time instant is only influenced by K,
having those magic K values you listed minimizing the energy left in the
primary.
But in the literature the K "magic" values are typically found according to
another criteria, namely maximum voltage developed at the secondary. The
procedure relates tuning ratio (uncoupled primary/secondary frequency
ratio) and
K to the maximum voltage gain, resulting in a set of [tuning_ratio,K] for
obtaining maximum gain. The maximum gain is 1.18*sqrt(L2/L1) when K=0.546 and
f1/f2=0.735 (paper from B.T.Phung).

Have you been investigating how these two families of K values compare with
each
other?

Regards