Re: Gap Losses (II) Re: Primary Heating

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Paul,

On 18 Mar 2002, at 11:27, Tesla list wrote:

> Original poster: "Paul Nicholson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <paul-at-abelian.demon.co.uk>
> 
> I wrote:
> > ...the energy lost into the gap over a cycle is the integral
> > of V(t) x I(t), and that the Q is then 
> > 
> >  pi * Lpri Ipeak^2/integral{ V(t) * I(t); over the cycle}
> > 
> > for that cycle at least.  Has anyone used one of those fancy 
> > digital scopes to measure this?  If so, did the gap energy lost
> > on each cycle account for the ringdown envelope, or did you have
> > to add in a significant fixed R.
> 
> Malcolm wrote:
> > In answer to your first question, no. In answer to the second, it
> > would be interesting to know the relative proportions for
> > different circuits. 
> 
> The same ringdown capture technique that we're discussing for
> secondary Q variation could be applied to this.  The software could
> extract the VI characteristic of the gap from the waveform.
> This could be done an easier way: simply by putting gap V to the
> y-amp and gap I to the x-amp of the scope in xy mode.  But to get
> the total gap energy lost, you would need to get the data into a
> PC, I think.
> 
> Indeed, the overall TC efficiency could be measured quite
> accurately by digitising the just-below-breakout gap VI waveforms
> over a whole beat or two.  That would give enough info to extract
> the total loss, and to separate gap loss from everything-else loss.
> 
> Effective k factor and beat frequencies could be extracted quite
> accurately too. 

We've already done both and have found that one-way transfer 
efficiencies can exceed 90% - a figure which obviously depends on the 
physical attributes of the coil being analysed.

> Might be time for me to start a new program - a general purpose
> thing that analyses TC waveforms and spits out numbers.  As a TC
> setup tool, it would be second to none.  But how many people
> have digital scopes that can download to a PC? It seems that
> there could be lots of potential here for breaking some TC
> measurement barriers with this kind of approach, so what are the
> cheap options for scopes or A/D converters?
> --
> Paul Nicholson
> --
 
I would like to offer my services since I have often used a 
digitizing scope in the past (things were different then) but am not 
in a position to do so now due to time and space constraints. I would 
like to say that things could be different in the future but have no 
way of knowing when.

Regards,
Malcolm