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Re: Sparks jumping from 4' to 9' (was Re: 20 joules)

Original poster: "Bob (R.A.) Jones" <a1accounting@xxxxxxxxxxxxx>

Hi Steve
> Original poster: Steve Ward <steve.ward@xxxxxxxxx>
>
> You bring up another interesting observation.  CW (continuous wave)
> output seems to be limited to short brushy sparks (they dont grow
> enormously despite the continuous transfer of power).  Now, its simple
> enough to do a direct comparison between a SSTC thats running pulsed
> (say a 8.33mS pulse, common for 60hz driven SSTCs) or running CW.  The
> CW sparks seem to be a bit shorter for a given input voltage.  I dont
> have enough power to handle a BIG CW coil so i cant compare the two as
> the sparks get much longer than 10-12".  But at smaller powers (under
> 2kW), it seems that just the act of interrupting a C-W coil allows it
> to produce better sparks.  But maybe i am just being fooled by the
> filter capacitor voltage getting dragged lower with CW... Perhaps i
> will do a more complete comparison between CW and pulsed this winter
> when these old-style SSTCs are more appropriate for indoor coiling
> ;-).
>

Perhaps you can perform a slightly different experiment .
Adjust the top load voltage in both cases to the same peak voltage and then
compare the average spark lengths.

Even with the same input supply voltage the top load voltage of the pulsed
coil could be much higher (x2) and the peak power even higher (x4) then the
CW coil.
The actual ratio depends on what mode (primary/secondary tuning versus drive
frequency) the coil is operating in.

Sparks are very nonlinear and hence could have some very strange behavior.
But I suspect that if the peak voltage in both cases is the same then the
spark lengths will be the same or smaller for the pulsed coil.

At a constant input voltage, it is probably not the interruption of the
output that allows longer sparks.  Its that the interruption causes a
transient that generates a larger output voltage and hence longer sparks.

Robert (R. A.) Jones
A1 Accounting, Inc., Fl
407 649 6400