Auto Quenching - OOPs!! forget that one ;-)

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi All,

Disregard yesterday's post and my ideas about "auto quenching".  As it
turns out, the effect does not exist.  It was just a computer modeling
error on my part.  The way I had it set up allowed the firing voltage to
vary as I changed the coupling.  As I worked with my coil last night it
seemed that something was really wrong with the idea.  I churned through
the models today and found the problem.  The proper peak voltage vs.
coupling graph, even with all the losses, looks like this:

http://hot-streamer-dot-com/temp/OLTC08-29-01.gif

Probably exactly what Marco and Antonio would agree with ;-))

Sorry if I caused any confusion.

Cheers,

	Terry

====================

>Hi Antonio, and Marco too,
>
>My small coil was designed for auto quenching using these methods.  "Auto 
>quenching" is a big subject I was always going to write up "someday"...  I 
>never did...
>
>Here is the "short" explanation...
>
>When you consider the losses of Rpri, Rsec, and streamer loading, the coil 
>looses power very quickly.  Subtle sweet spots indicated by the lossless 
>case are swamped by these giant losses.  Lower quenching allows all the 
>primary's energy to be impressed on the secondary in a single burst for 
>maximum secondary voltage.  I looks like a "ball" where the secondary rings 
>up to maximum voltage and then all the system's energy is gone.  There is no 
>second or third notch.  Modeling definitely suggests this is the optimal 
>situation and my small coil is a great performer given it's power.  My work 
>tonight with the OLTC shows that this is a great value for k as well.  It is 
>hard to "see" without actually "being there" or having a nice paper like 
>Marco's to explain it...  But just imagine the coupling is set to pump the 
>maximum voltage into the secondary in one single shot where we trap it 
>before all these nasty looses ruin it.
>
>It may seem that high coupling is good, but it tends to restrict the 
>secondary voltage from ringing up to the best value too.  It seems that 
>hitting the secondary with a well planed single burst at lower coupling 
>allows the highest secondary voltage to build up in the "high loss" case.  
>Remember, that a streamer in a 1000 watt coil may be eating 300 watts of 
>power!!  You just "can't" ignore that giant load and it's effects!!
>
>I know it is "unpleasant", but you really "need" to consider Rpri, Rsec, and 
>streamer loading in defining the best values for k.  Since there are no 
>closed form equations for the high loss case (or at least they have never 
>been found.  Perhaps a problem for computer math programs like "Maple"), you 
>will have to use iterative computer programs like MicroSim to find the
effects.
>
>"My bad" for never following up on all this before...  But it is a giant 
>subject I never was able to grab hold of and explain properly...
>
>Cheers,
>
>	Terry
>
>
>At 10:36 PM 8/28/2002 -0300, you wrote:
>>Tesla list wrote:
>>> 
>>> Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
>>> 
>>> Hi All,
>>> 
>>> I ran various MicroSim models with K going from 0.05 to 0.25 with primary
>>> resistances of 0.5, 1.5, and 2.5 mOhms.  I found the resulting peak
>>> secondary voltages:
>>> 
>>>         http://hot-streamer-dot-com/temp/OLTC08-28-01.gif
>>> 
>>>         http://hot-streamer-dot-com/temp/OLTC08-28-02.gif
>>> 
>>> I think the dip in the yellow line at 13 is a mistake in my data.  In the
>>> low loss (r=0.0005) case you can see the effect of sweet spots above
k=0.20.
>>
>>The results seem strange. Increasing the coupling should always reduce
>>the loss, increasing the maximum secondary voltage. The sweet spots
>>don't
>>make great difference at these levels of coupling. The large increase
>>observed for low coupling is very strange. Are you sure that
>>you are measuring the output voltage with both polarities?
>>
>>Antonio Carlos M. de Queiroz
>>