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Re: Delta Fo (fwd)
---------- Forwarded message ----------
Date: Sat, 18 Jul 1998 20:16:27 -0600
From: terryf-at-verinet-dot-com
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Delta Fo
Hi Gary,
At 01:51 PM 7/18/98 -0600, you wrote:
>From: Gary Lau 18-Jul-1998 1152 <lau-at-hdecad.ENET.dec-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: Delta Fo (was How to raise secondary)
>
>While I was ready to embrace the theory that the attached streamers were
>responsible for adding to Ctop, the point raised that the streamers only
>occur _after_ ringup pretty much discredited that in my mind.
>
>Instead, what ever became of the theory that, in operation, an ion cloud
>with a persistence greater than the bang interval, exists about the top
>terminal, effectively increasing it's size and capacitance? Seems to fit.
>
>Gary Lau
>Waltham, MA USA
>
>
I am now convinced that there is a rise in secondary capacitance. If it is
due to streamers or corona of the top terminal is still somewhat of a
question. Perhaps if I were to lower the K of my coil so that the ringup
was slowed down and measure the time interval between each zero crossing of
the secondary voltage we could see if corona or streamers cause the
frequency shift. I would have to capture the whole event in one scan to
eliminate variation error from spark to spark. I can't do the big arcs in
my basement :-( but I certainly can get to the corona points and such. If
there is like a 5% shift just do to corona then maybe that is the whole
shift right there. Or, if there is little shift just before the breakout
point, then the arcs must be responsible for the shift. I feel an
experiment coming on!...........
And here it is:
Time uS Difference Frequency
0 0 0
4.5 4.5 111111.1111
9 4.5 111111.1111
13.6 4.6 108695.6522
18.1 4.5 111111.1111
22.7 4.6 108695.6522
27.2 4.5 111111.1111
31.8 4.6 108695.6522
36.3 4.5 111111.1111
40.8 4.5 111111.1111
45.3 4.5 111111.1111 <-Quench Point
49.9 4.6 108695.6522
54.3 4.4 113636.3636
58.9 4.6 108695.6522
63.3 4.4 113636.3636
67.9 4.6 108695.6522
72.3 4.4 113636.3636
76.9 4.6 108695.6522
81.3 4.4 113636.3636
85.9 4.6 108695.6522
Note that from 9 to 40.8 uS the average is 110.0 kHz. but from 49.9 to 85.9
uS the average frequency is 111.1 kHz. So at higher voltage, the frequency
seems to have gone up slightly.
It is sort of beautiful, scope to excel to Eudora. Took about 10 minutes.
The granularity of the scope's sampling rate is sort of a problem. There
was no real visable corona breakout but an occasional small (a few inches)
streamer. I don't see any big frequency shift due to just a high voltage on
the terminal. This would suggest that the frequency shift mostly lies with
the long streamers themselves. The terminal voltage reached about 250kV on
my two-salid-bowls-taped-together top terminal. My gap was adjusted to the
just-before-breakout point. I should have easily been able to see say a 5
or 10 percent shift. I see nothing, however.
Isn't science wonderful!
Terry Fritz