RE: Primary loss measurements

[Terry Fritz <twftesla-at-xxxxxxxxxx>]

Hi Gary,

At 09:36 AM 11/13/2000 -0500, you wrote:
>To put my loss-resistance measurements in perspective, I found the number of
>Watts that the incremental resistance would dissipate in a running coil.  I
>user Terry Fritz's LTR10-31 Microsim schematic to represent the coil and
>found the RMS current in the tank circuit - 9.77 Amps.
>
>The additional resistance that I measured on my coil due to the proximity of
>my NST, gap, caps, and toroid was 0.024 Ohms.  This would dissipate 2.29
>Watts - not a big deal.
>
>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
>Waltham, MA USA
>

I measured the ringdown time with a storage scope and probably an antenna
back then and found the equivalent ringdown using MicroSim.  that is with
just the primary cap, gap, and inductor in the circuit with no secondary
present.  I did that years ago and have not thought about it since but I
think I rechecked it for the paper in late 98.  My small coil with the
rotary gap is 1.5 ohms and was measure much more recently when perhaps I
knew what I was doing. :-)  I don't remember the gap I used with the big
coil measurements but all the models and such work well with 3 ohms.  0.43
ohms would show up in the measurements if I were off by that much.

This is sort of an unexplored area so maybe there are sectrets to be learned!!

Cheers,

	Terry