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Re: NSTs and Cap Charging.
In a message dated 99-04-12 05:52:42 EDT, you write:
<< Original Poster: TeslaTec-at-webtv-dot-net (Tony R Greer)
Tony,
It sounds like at a lower voltage the gaps are firing at less than
120 BPS which would be expected, and the input current effects
you're seeing support this view. At the "notch" it may be firing
at 120 BPS. I think a sync gap would be very helpful.
John Freau
> Malcome, John, Richie, Terry, and All,
> Just thougt I'd report on some observations while making adjustments to
> my 8" x 34", NST powered coil that might have some relation to this
> thread. (Quick specs; 15,000 V / 150 mA NSTs. C=.0267 uF. Spark
> gap=static single gap with vacuum airflow quenching (Gary Lau style) ,
> Variac input control to NSTs. Transformer voltage and current were
> chosen to to resonate at 60 Hz with Maxwell pulse caps on hand.........
> After cleaning and adjusting the gap to about .36", I started to
> increase the Variac setting, while watching the input Volt and Ammeter,
> and the output mA meter. the gap started fireing at about 30 Volts
> input, and at about 60 Volts or so, floating streamers start to break
> out. At about 90 volts in, the Ammeter is reading erraticaly between 25
> and 30 Amps, streamers are multiple and about 3' long, and the noise
> from the gap and streamers is very ragged and more like 'white noise'
> (many frequencies). But when 96 volts was reached, input current
> SUDDENLY droped to about 16 Amps, and the output current droped from 200
> mA to 100mA, and became very steady. Streamers shrunk slightly (maybe
> 10-15%), but most noticeable was the different sound of the gap and
> streamers. At between 96 and 98 Volts, the noise became a steady buzz,
> like a single note. Probably firing in sync with the line, because
> raising the Voltage past 98 Volts would again cause the current to
> double and the noise would regain it's raspy sound, and streamers
> regained their original length. Past this point, no other 'notch' was
> found, although streamers grow to almost 6' at 120Volts input at about
> 35 Amps. Also, widening the gap to .375" moved this 'notch' up to 100 to
> 102 Volts. Another thing of intrest is this 'notch' effect only happens
> for a few minutes after removing the oxide from the sparkgap (large
> copper endcaps w/ 3/8" holes in the center for airflow). After a few
> more minutes, the safety gaps start to fire. A light sanding of the gap
> restores original performance. I think a sync RSG would eliminate those
> problems and improve performance. What do ya'll think? I really haven't
> drawn many conclusions to these effects, but thought it might provide
>some additional information for this thread. Any comments, suggestions,
> or questions would be greatly
> appreciated.............................................
> T-coiler Howdys from Texas !
> Tony Greer
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