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# Re: Cap safety gap (renamed) (fwd)

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---------- Forwarded message ----------
Date: Thu, 18 Dec 1997 09:51:29 +1200
From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Cap safety gap (renamed) (fwd)

Hi Antonio,

> Date: Wed, 17 Dec 1997 14:14:06 -0800
> From: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: Re: Cap safety gap (renamed) (fwd)
>
> Tesla List wrote:
>
> > The only
> > possible source of energy apart from the transformer and boost
> > inductor is back-feeding from the secondary. This can only be a
> > factor if the gap opens when a significant amount of energy remains
> > in the secondary (gap opens at a time of minimum primary activity).
> > Experiments in the past suggest this is unlikely but I can't
> > completely rule it out.
>
> Maybe if the gap -closes- when there is enough energy in the
> secondary, left from the previous cycle. This can really cause
> the primary voltage to ring up to a higher voltage than the normal.

If phasing is right which is statistically unlikely. But
additionally, you are talking break rates in the multi-kHz region.
Based on further results from someone else experienceing a similar
problem, I am back to ruling that out completely at the break rates
we normally operate at. I can support my claims with photos from the
scope.

> >      Energy stored in the inductor while the gap is closed is
> > inversely proportional to the inductance but proportional to the
> > current squared, the nett result being that the smaller the
> > inductor, the more energy is stored and the faster it can recharge
>
> No. The energy is directly proportional to the inductance: E=0.5*L*I^2
> Small inductors "charge" faster, but store -less- energy.

If L is halved and Tcharge remains the same, I must double if V
remains constant. I stand by what I said.

Malcolm

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