Re: Output arc lenghts (fwd)

---------- Forwarded message ----------
Date: Tue, 21 Jul 1998 08:52:06 EDT
From: FutureT-at-aol-dot-com
To: tesla-at-pupman-dot-com
Subject: Re: Output arc lenghts (fwd)

In a message dated 98-07-21 00:26:24 EDT, you write:

<< John,
> How does that work?  I thought a static gap tied the firing rate to the AC
> mains cycle (100pps for 50Hz, 120pps for 60Hz).  I figured the only way to
> change firing rate was with a variable speed RSG.  I'd do almost anything
> to avoid building the dreaded RSG!  Please clue me in. 
> Greg

If enough charging current is available to the tank capacitor, it will
be able to fire multiple times per AC half cycle.  Even with relatively
low current, this can occur if the capacitor is small and the gaps
are closely spaced.  For instance I
built a very small coil using a .0015uF capacitor, and powered up
using a 10kV,23ma oil burner ignition transformer, and the static
gaps fired about 5 times per half cycle or so.  (13" sparks)  Since a pole 
transformer has so much current available, multiple firing can occur
with a larger capacitor.

The number of times the gap fires per half cycle also depends on
the gap spacing relative to the voltage available.  With a wide spacing, the
cap will charge up to a higher voltage, but this takes more time, 
and will reduce the firing rate.  Narrow gaps will let the gaps fire
sooner (at a lower voltage), so the gaps will fire more often.

John Freau