Re: Vortex gap loss measurements

["Malcolm Watts" <M.J.Watts-at-massey.ac.nz> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

On 2 Sep 00, at 18:36, Tesla list wrote:

> Original poster: "Daniel Boughton" <daniel_boughton-at-yahoo-dot-com> 
> 
> Gary:
> 
> This is a very interesting experiment. First, when you
> measured the slope during the ring down, did you see
> the same size decrement of each succesive oscillation?
> Is this what you mean by linear as oppossed to
> logarithmic? Traditional wisdom purports that the
> decay is according to V(t)=V(i)e^-rt where V(i) is the
> forced initial potential on the capacitor. Your
> results are very interesting however in that it flies
> in the face of convention. The derived equation must
> be something like V(t)= V(i)*-krt. I wonder if without
> the secondary it is linear due to resistive losses
> only. Without the secondary the additional absorption
> of energy via the secondary mutual inductance is
> missing which accounts for the linear decay? Also what
> I found interseting was that with the gap distance the
> slope remained constant. I would have expected greater
> gap resistance at further distances but it seems that
> the plasma provides a constant resistance no matter
> how wide the spark gap is set (within reason of
> course-I 'm sure at a foot the resistance would be
> substantial as compared to 300 mil).

The linear decrement of a ringing RLC circuit which has a gap 
in series with it was discovered by Stone circa 1914. The 
Corums mention it in their literature but unfortunately never 
went on to use the information in their modelling. The linear 
decrement is entirely due to the gap characteristics. An RLC 
circuit by itself produces only a logarithmic decrement. This 
clearly shows that modelling the gap as a resistancwe does not 
work. You cannot apply the classic time constant equations to 
this situation. The gap is dissipative but that is where the 
similarities with resistance end. I analysed this and wrote a 
note on it several years ago. It is important to note 
(ultimate pedantry) that you *cannot* ascribe a value for Q to 
the primary if the primary includes a gap. You can compare 
various primaries with each other by comparing the ringdown 
slope (gentler is obviously better).

Regards,
Malcolm