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Re: Primaries
Malcolm wrote:
>
> I have some questions I would appreciate some answers to.
> (1) To Greg Leyh : You mentioned some figures for gap current and
> gap conduction voltage the other day. How did you measure those?
The gap current was measured using a Pearson wide-band CT, attached
to a storage oscilloscope. The gap voltage was measured with a
Tektronix P6015 wide-band HV probe, connected to a (floating!)Fluke 97
battery-powered scopemeter. Front panel operation was accomplished
using an 18" fiberglass stick. The voltage waveform was divided by the
current waveform to obtain an average Rgap = 0.65 ohm at 1800 A rms.
> An analysis based on a dynamic primary Q of 10 suggests that the
> lower in frequency I go, the smaller the gap losses become.
> If anyone has any input on this or comment to make I would
> welcome it. I am just about at the end of the rope with regard to the
> primary. I had hoped late last week that gap losses might reduce with
> a drop in gap current but it seems that hope is doomed.
Are you assuming that the unloaded primary Q will always be 10, regardless
of Zpri? It seems that your estimates of Rgap are somewhat pessimistic.
An ionized path of air is a much better conductor than it has any right to be.
-GL