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Re: Secondary Spark Capacitance (was How to rise the secondary?) (fwd)



---------- Forwarded message ----------
Date: Wed, 22 Jul 1998 17:34:18 -0600
From: terryf-at-verinet-dot-com
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Secondary Spark Capacitance (was How to rise the    secondary?) (fwd)

Hi John,

        
        I would think that a digital scope could capture the secondary
waveforms and measure the change in frequency very easily.  Then the
capacitance change could be easily found.  Simply changing the primary
system is probably close but there are many sources for error.  Of course,
to get the best coil operation, tuning the primary is perfect.  For us
"scientific" people, the scope method should give a very close measurement
of the capacitance throughout the arc event.  I am going to try to do work
in this area as time permits.

        Terry Fritz



At 09:33 PM 7/21/98 -0600, you wrote:
>Date: Tue, 21 Jul 1998 05:10:16 +0000
>From: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
>To: Tesla List <tesla-at-pupman-dot-com>
>Subject: Re: Secondary Spark Capacitance (was How to rise the   secondary?)
>
>
>  Richard, All -
>
>  Thank you for again explaining this test. I somehow missed your previous
>posting. The secondary spark capacitance would be difficult to measure
>because this change in the secondary capacitance cannot be measured
>directly. If I understand your test correctly you measured the change in
>secondary capacitance indirectly by measuring the change in primary
>inductance. This sounds possible but there are problems.
>
>  One of the problems is in measuring the change in the primary inductance
>that is directly related to only the capacitance of the sec spark. The
>electric field around the coil and the ion cloud could also be involved.
>Another problem is that there are two different types of tests being used,
>low voltage with a signal gen and high voltage with power on. The tuning
>errors of measurement would be hard to eliminate. These errors could be what
>you are finding in the tests.
>
> A problem also arises in the fact that the spark is on for such a small
>period of the break cycle. For example, the break peroid for 120 BPS is 8333
>us. The time the spark is on is only about 1/3000 of this time. The spark
>capacitance would not have much effect. The ion cloud and the electric field
>capacitance, if any, would have more effect.
>
>  Hopefully, you and other coilrers in the future will make more tests and
>confirm what effect the spark capacitance has on the TC operation. To my
>knowledge you are the only one who has researched this interesting
>possibility. Are there other coilers who have performed these tests?
>
>  John Couture    
>
>----------------------------------------------
>SNIP>>>>>