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Sonderman Testing (fwd)
---------- Forwarded message ----------
Date: Fri, 26 Sep 1997 18:47:25 -0400 (EDT)
From: Esondrmn-at-aol-dot-com
To: tesla-at-pupman-dot-com
Subject: Sonderman Testing
Last night I finally got my coil fired up again. Changes since last testing
were replacing all the contacts on the rotary and eliminating the static gap
in series with the rotary. The spark gap across the capacitor is set down to
5/8". This is my 6" coil with a .025mfd C.P. cap, powered by a 14.4 kva pig.
The first project was to find the best tune at low power. I had a ground
wire set up maybe 3.0 feet from the toroid and a wire laying on the edge of
the toroid pointing at the ground wire target. The welder was set at
minimum. It again wouldn't run worth a damn with the resistor bank in
parallel with the welder so I unplugged it, now using only the welder for
ballasting. I noticed immediately that I had much more consistent firing of
the rotary spark gap. It started to fire at maybe 25% of full variac power.
As I increased power, the safety gap across the cap would start firing. I
decided if the safety gap firing was due to an out of tune condition, I
should be able to tune the system by finding the tap on the primary that
would allow the highest setting on the variac without firing the safety gap
across the capacitor. I plotted a whole range of tap positions and got a
reasonable shapped bell curve, which is what you would expect. The best tune
position was between 11.75 and 12.0 turns on the primary. This also
coincided with the hottest discharges from the secondary.
Now I opened up the safety gap across the capacitor to about 1.0". I was
very surprised to find out that I could only open up the variac to maybe 60%
of full power before the safety gap across the cap started firing again. It
must be in tune, why is the safety gap firing????
I turned the variac down a small amount where it would run without firing the
safety gap. Increasing the primary current produces hotter sparks up to a
point then at full current, the spark length falls off noticeably. This is
puzzeling.
Increasing the rotary gap speed causes hotter sparks for a while and then
falls off past a certain point. This is unlike my past experience where this
coil was hungry for power and would continue to produce better sparks as I
increased the rotor speed - as fast as I dared turn it up.
I could certainly use some help here. This coil used to produce 80"
discharges and now I can't seem to get past about 36" to 40". Something is
not right and I can't find it. If the primary and secondary are in tune, why
can't I apply full voltage? I have the rotary gap across the high voltage
mains, should I swap it with the cap and put the cap across the mains and let
the rotary act as a safety gap for the cap - and remove the existing safety
gap across the cap - as Peter E. suggested the other day? I really can't
afford to blow up any more capacitors. By the way, the main safety gaps
connected near the output of the pig, with the center post grounded, never
did fire in any of these tests. It never has fired very often in the past
unless I was getting secondary hits down into the primary.
Thanks, Ed Sonderman