Re: Rotary Sparkgap
Subject: Re: Rotary Sparkgap
From: "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
Date: Thu, 29 Feb 1996 10:31:42 +1200
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Continuing on this from Jim Fosse....
> But it most certainly ddoes resonate
> >at low-level, and at least three people here have encountered diffi-
> >culties associated with resonances under normal running conditions.
> >I think the 360mA IS invalid. BUT, any resonance implies a higher
> >current than the limited value into a resistive load. I have opened
> >up a spark gap to well over the rated peak voltage and I know Ed
> >Philips has too.
> I'm sure I have also!
> But is this due to the TC primary L and C or to the neon L and C?
> I can't answer this right now, I tore everything apart tonight to measure my
It has to be the transformer inductance and capacitor IMHO for
two reasons : (1) The spark gap has to initially fire which it
can't do if the transformer won't deliver sufficient energy to
charge the cap up to that point (note that Cp and Lp of the coil
is a mile off resonance at 50/60Hz), and (2), if the capacitor
voltage at ANY stage does exceed that of the transformer, where
does the EXTRA energy come from - bear in mind Vcp = SQRT(2Ecp).
> >> If I remember correctly, the leakage inductance of a transformer is
> >> measured by shorting the secondary and then measuring the
> >> inductance of the primary.
> >Shorting the primary should achieve the same end as shorting the
> >secondary IMHO. The idea of using a low-Z generator was to achieve
> >exactly that.
> NO, real world here! the secondary is so much BIGGER and futher away from
> the core than the primary (of the neon) that it will have a much larger
> leakage inductance than the primary will (both cases with the shunts removed!
I must have misinterpreted. I was measuring the TOTAL secondary
inductance, not just leakage. Sorry bout that.
Thanks for the tables.