raise the secondary.... (fwd)
---------- Forwarded message ----------
Date: Sun, 12 Jul 1998 16:18:34 -0600
Subject: raise the secondary....
I can measure the frequency of each ringdown cycle to about 1% accuracy. I
do not see any frequency shift from streamer to non streamer operation. I
think the capacitive effect is very small if it exists. Since the secondary
is isolated from the primary after the first notch (We have all raised our
secondaries haven't we? :-)), any frequency shift would not affect the coil
in any way (streamers tend to break out just after the notch point).
>From: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
> Richard, et al -
> I agree the TC operating conditions are different from the instrumented
>conditions. The capacitance due to streamer loading, etc. would change the
>capacitance (Cs) of the secondary circuit and change the operating
>frequency. However, my tests indicate this change is very small.
> A much larger change in capacitance occurs when the toroid, etc . is
>mounted on the TC. The change in toroid capacitance from the calculated free
>space capacitance can be as much as 30%. This can create a large change in
>operating frequency. The calculated free space capacitance should not be
>used to calculate the operating frequency without a correction for the
>toroid being mounted on the TC.
> My TC computer program ignores the streamer loading, etc, capacitance
>because I did not have this information when the program was being
>developed. However, the tuning indicated by the program varies little from
>the actual tuning of the operating coil when the corrected free space
>capacitance of the toroid is used. This would indicate the streamer loading,
>etc. capacitance has little effect.
> Do you (or R. Hull) have any test data that would show how much the
>streamer loading, etc. capacitance is and how much it affects the operating
>frequency after the toroid mounting capacitance change is taken into
>consideration? As I indicate above the operating frequency change for only
>the streamer loading, etc. should be very small.
> I like to look at the longest sparks as the condition where the TC input
>energy equals the output energy plus the losses. When the losses are the
>lowest the maximum energy appears in the secondary circuit and the sparks
>are the longest. In other words the longest sparks happen when the maximun
>energy at the maximum potential occurs on the topload. The length of the
>first spark depends on the potential and additional sparks are then modified
>by the ionozation of the air. The energy and potential are related by
> Joules = 1/2 Cs Vs^2
>This should be multiplied by an efficiency if one can be determined.
>Note that a large amount of power can mean large currents and low potential
>producing short sparks.
> John Couture