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RE: Primary loss measurements
Hi John:
Yes, thinking more about it, I'm sure you're right. The equivalent
resistance calculation that Bert suggested takes into account only
inductance and time to ringdown. If a ringdown were to start at a higher or
lower initial voltage, the calculated resistance would also be
correspondingly lower or higher. Also, I believe Terry has a much higher
inductance primary than what I was using, and that would also directly
affect the calculated resistance. I'm in the process of rebuilding by coil
with a much higher L primary to put into practice what we both have found
about gap losses and high surge impedance. It will be interesting to re-do
the loss measurements due to primary proximity and see if they scale with
total tank resistance, or stay the same.
Regards, Gary Lau
Waltham, MA USA
>Gary,
>
>I suppose a lot would depend on the initial voltage and current, since the
>gap losses are non-linear. If Terry's test used different voltages and
>surge impedance's, etc., the losses would be different. It's hard to
>to use just one Rgap figure, because the Rgap changes during ringdown,
>and depends on so many parameters.
>
>I tend to think that the losses in a rotary wouldn't really be much
>different than in the vortex gap. I think the difference is caused either
by
>the different parameters of the circuit and/or by the type of simulations
>or analysis that Terry used compared with your measurement method.
>
>John Freau
>> Terry - how did you arrive at the 3 Ohm Rgap value in your model? When
I
>> made my primary ringdown measurements, Bert Hickman showed that an
>> equivalent gap resistance could be found by noting the duration of the
>> linear ringdown, and finding R = 2L/t. For my vortex gap, R came out to
>> 0.43 Ohms, and would also include the AC and DC resistance of everything
in
>> the tank circuit, equivalent to your Rgap. Is your RSG really that much
>> more lossy?
>>
>> Gary Lau