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Re: Safety gap issues



Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Dmitry,

I think Adam dropped a term in his equation and should be:.

Vsec = Vpri * sqrt (Cp/Cs)

If one uses Vpri_rms, one might think one gets Vsec_rms. However, I really don't think it correlates to the secondary voltage cause the secondary only sees the resonate frequency stuff where as the primary has that as well as the 60 Hz charging voltages. Seems like one would need to filter out the 60Hz stuff from the primary waveform to try to use RMS (or compute RMS during the bang time only). The equation is based on energy balance where the primary energy is at the time of gap firing so it is the FIRING voltage that is important, not RMS and not PEAK, I believe. Of course, PEAK and FIRING will be the same for static gaps.

Gerry R.

Original poster: Yurtle Turtle <yurtle_t@xxxxxxxxx>

That's what I meant, though my typing fingers got
ahead of my brain. I was trying to point out that he
shouldn't use RMS values, but should instead use peak
values for this.

thanks for clarifying this.

Adam

>  > E = .5CV^2
>  > assume Epri = Esec, that gives you
>  > .5CpriVpri^2 = .5CsecVsec^2
>  > rearranging give you
>  > Vsec=sqrt(Cpri/Csec)
>  >
>  > Volts are RMS, Csec includes the secondary's self
>  > capacitance and the topload.

Original poster: "Dmitry (father dest)" <dest@xxxxxxxxxxx>

>  > It's the first. This is basically a conservation of
>  > energy equation. It also assumes no losses, which
>  > isn't realistic, especially if you don't have a good
>  > spark gap.
>  >
>  > E = .5CV^2
>  > assume Epri = Esec, that gives you
>  > .5CpriVpri^2 = .5CsecVsec^2
>  > rearranging give you
>  > Vsec=sqrt(Cpri/Csec)
>  >
>  > Volts are RMS, Csec includes the secondary's self
>  > capacitance and the topload.
>  >
> In the first equation above the voltage is usually defined as an actual
> voltage not rms.

it`s critical only for the energy calculation, but if we need to
calculate the voltage (rms) at the secondary - what`s the difference?
nil.