ASRG & DC power oddity

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Original poster: "J. B. Weazle McCreath by way of Terry Fritz <twftesla-at-qwest-dot-net>" <weazle-at-hurontel.on.ca>


Hello Coilers,

The milder weather we're having has let me carry on with some of my
experiments with an ASRG and the DC power supply I'm developing and
I've noticed an oddity.

I'm using a 3450 RPM, 1/12 HP motor to turn a 6 inch teflon disk in
which there are two flying electrodes passing thru the disk, spaced
180 degrees apart.  The two fixed electrodes are on either side of
the disk, meaning I get an alignment twice each revolution, or 120
breaks per second.

I notice that the motor has what I would term a beat note to it when
running, the beat occuring roughly at one second intervals, sounding
much like a twin-engined propeller driven aircraft when the engines
are out of sync.  The spark when firing seems to follow this beat as
well, and you can actually see the intensity of the arc varying with
the beat note from the motor.

The power supply is a twin MOT with the classic half wave doubler to
give me about 11 KV unloaded.  I'm feeding the output of the doubler
to the ASRG through two charging chokes (MOT secondaries) of 8.5 mH.
The doubler cap is 1 uF., and the tank cap is 0.011 uF., yielding the
recommended ratio as others have found.  I'm using my testing primary
which in combination with the tank cap is resonant at about 430 kHz.
and there is no secondary in the test setup.

Can anyone on the list shed any light on this "beat note" behavior?
Is it possible that my motor is under-powered to turn even a modest
sized disk like I'm using?  Any suggestions are most welcome.

73, Weazle, VE3EAR/VE3WZL

Listening: 147.030+ and 442.075+
E-mail:    weazle-at-hurontel.on.ca
           or ve3ear-at-rac.ca
Web site:  http://www.hurontel.on.ca/~weazle