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Re: Safety gap issues



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

Hi Dmitry,

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

> 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.

the primary sees 60 hz charging not always - for example, when Cpri is
connected across the transformer, so be careful with such statements :-)

Im sorry, when I said primary, I was refering to the primary capacitance not the primary inductance. This was assumed since the equation was derived based on energy in the capacitance. Cpri across the transformer sees 60 Hz charging same as if spark gap is across transformer.

but it`s not important, as i of course mentioned not the Vprimary and
Vsecondary rms, that depend from the duty factor & damping factor and
from many other things in the _real_ coil - it`s obvious too.

I think we both understand that RMS can be used in the energy balance equation, if the 60 Hz stuff is not included in the calculation of Vpri_cap_rms. I also agree that this is not an important issue since most everyone uses the energy balance equation in the context of using the firing voltage to find the theoretical secondary peak voltage.

Vpri represents Vprimary_cap and Vsec represents Vsecondary_cap:
Csec includes the secondary's self capacitance and the topload.
as the secondary is connected in parallel with Cs+Ct=Csec.

Yes.

the equation:
> .5CpriVpri^2 = .5CsecVsec^2

is true for the ideal case - when there`re no losses, right?

Right..

but then
in the secondary we`ll have the undamped oscillations and then
Vpeak=sqrt(2)*Vrms - i spoke just about this :-)

True for constant amplitude sine wave. But even in a lossless system (above), the secondary rings up as the primary rings down so the output sine wave does not become constant amplitude until the spark has quenced. At this point in time, there is no current flow in the primary (other than charging current) so nothing to compare (equation doesn't apply).

Gerry R