From: "Terrell W. Fritz"
Date: Fri, 13 Sep 2002 17:06:22 -0600
Subject: Re: [TSSP] Top Voltage
Hi Paul,
At 11:00 AM 9/12/2002 +0100, you wrote:
>I modeled the coil details to get:
>
>With toroid: 37.752 kHz
>With toroid + rod: 37.479 kHz
>With toroid + rod + 1.833 sphere: 37.138 kHz
>
>I'm not sure whether rod and sphere were in place when you pinged
>with toroid. Assuming they were, we get
Nope. that was just the bare toroid without the ball.
>
> Measured Modelled Error
>f1: 37.801 kHz 37.138 kHz -1.7%
>f3: 113.550 kHz 113.929 kHz +0.3%
>f5: 171.773 kHz 174.632 kHz +1.7%
>
>so perhaps rod and sphere weren't in place?
>
>Specific surface field gradient is highest on the sphere,
>at 0.300 kV/cm/kV for the largest sphere, thus breakout would
>be at a topvolts of 26/0.3 = 87 kV topvolts. The smallest sphere
>gives 0.479 kV/cm/kV to give a breakout at 26/0.479 = 54kV.
>
>These can be referred to the base current and primary voltage,
>
> Vtop Ibase Vpri
> (peak) (peak) (peak)
>Small sphere: 54kV 0.6 amps 80 V
>Large sphere: 87kV 0.9 amps 130 V
>
>So by my reckoning, all three spheres should have been breaking out
>comfortably with the base currents shown in S1-S3.gif.
>
>--
>Paul Nicholson,
>--
I got the response of the fiber optics as good as I could get:
http://hot-streamer.com/temp/PaulArc/020913/Tek00000.gif
Not really sure what it "is" but it seems tame and makes sense. The scale is
1amp of streamer (ball) current = 24.4mV on the scope.
So I tried to find the breakout on each ball and got the following:
#1 Small Ball
Vfire = 119 VDC
http://hot-streamer.com/temp/PaulArc/020913/Tek00001.gif
http://hot-streamer.com/temp/PaulArc/020913/TEK00000.CSV
#2 Medium Ball
Vfire = 191 VDC
http://hot-streamer.com/temp/PaulArc/020913/Tek00002.gif
http://hot-streamer.com/temp/PaulArc/020913/TEK00001.CSV
#3 Big Ball
Vfire = 226 VDC
http://hot-streamer.com/temp/PaulArc/020913/Tek00003.gif
http://hot-streamer.com/temp/PaulArc/020913/TEK00002.CSV
With the Big Ball, I spread the scale to get the profile of the spark.
http://hot-streamer.com/temp/PaulArc/020913/Tek00004.gif
The spark did jump around a little but I caught the most typical "good ones".
They like to occur as the secondary base current passes through zero (max
Vtop). They also still almost always go negative (perhaps you can check the
polarity against what you think is right to double check me there). The
breakout point was very consistent and easy to adjust. Should be fairly
accurate given altitude temperature humidity... I tried to clean the balls and
burn off the dust first.
In this case (the big ball) the breakout potential was causing about 100mV or 4
amp sparks! However, that puts 4 volts across the fiber sender which is too
high for it. The level is probably pretty distorted. I need to go down to a
0.1 ohm resistor...
I may also get out the plane wave antenna since it has a much better bandwidth
and such just to double check. Hopefully this will provide some entertainment
for now. Suggestions welcome ;-)) I'll try more "stuff" tonight.
Cheers,
Terry
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.