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Re: magnifier vs. classic tc (magnifier modeling) (fwd)
---------- Forwarded message ----------
Date: Sun, 29 Mar 1998 14:41:41 EST
From: FutureT <FutureT-at-aol-dot-com>
To: tesla-at-pupman-dot-com
Subject: Re: magnifier vs. classic tc (magnifier modeling)
All,
I did a little more work with the small magnifier setup. It turns out
that the behaviour (beat appearance-wise) is actually
the same with or without the point
installed onto the toroid (I turned up the power slightly, and this
may have made the difference now). The setup gives best spark
output with the secondary variable cap set at about 68pF, this is
the adjustment that gives what looks like one long (30uS) RF beat. BTW,
I've tried various positions for the pickup probe to the scope, cleanest
signal results from just placing the wire on the floor between driver
and resonator, I think this is picking up primarily the secondary output
waveform.
If I set the variable cap at 78pF (it used to give these short beats when
tuned to 164pF, so it changed now, maybe due to the slightly hower power,
and greater spark loading...have to check it all again) to
give a short 5.6uS beat, then the
sparks are a little shorter and quench is poor at the 6th RF beat notch.
This poor quenching is probably what is making the sparks shorter with
this adjustment. To benefit from a tight effective coupling, it is
necessary to be able to quench at one of the early notches, which so
far, I cannot do with this system. I may try raising the break-rate to
increase the spark loading to see if this helps, but in general it's hard
to properly quench these small systems.
Another thing I've noticed is that if the adjustment is made that gives
the 5.6uS beats, these beats seem to lose their *harmony* after
awhile (along the quenching waveform seen on scope), and the notches
become less deep after a number of them occur (within one bang)
and this may be degrading the quenching also. In contrast, if I set
things so I obtain the long (30uS)) beat, deep notches begin to form
near the end of the beat, which may help the quenching. Maybe if
I adjust the driver k, a point may be found that will improve the nature
of these beats over the entire firing duration. (I.e. magic value utilization
may help.)
It was also observed that the best spark output seemed to occur
when the after-quench beats were of the longest possible (100us?)
duration. It was difficult to measure these beats because of their
shimmering, interwoven appearance.
John Freau