RE: DRSSTC III Success 48" arcs from a 12" secondary!

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Original poster: <dhmccauley@xxxxxxxxxxxxxxxxxxxxxxxxxx>

Terry,

Not sure how much arc length is reduced from reducing pulsewidth in this
set-up.  Visibly, it appears arc length remains constant all the way down to
about 100us.  I believe this is around the point where most of the energy
has already been taken from the DC bus capacitors.  The current waveforms
would be indicative of this, although i'm still just collecting data (not
analyzing) at this time.

The only time i was really current limiting was during the first iteration
of my tuning study (1.00 turn from top as designated on my spreadsheet).
Current limit occurred during most ground strikes (at full voltage)

Yes, i am using a half-bridge, and my rails are approximately 0V and 395V.

With my new driver, when current limit is hit, the system will re-enable on
the very next interruptor pulse, so its very fast to re-enable.

But in summary, other than the 3 highest arc levels as shown on my first
iteration (1.00 turn from top) on the excel sheet, current limiting was not
occurring.

Hope this helps.

Dan





Hi Dan,

So you decreased the pulse width but increased the current limit to
go from 34 to 48 inches.  Normally I would think decreasing the pulse
width would lower the coil power and make the streamers shorter
regardless of the current limit.  Perhaps the coil is arcing far
early so it never used all the 300uS pulse width anyway ?

When the coil arcs to ground are you hitting a current limit then ?

I assume you are using a half bridge so the buss voltage lower rail
is 0 and the high rail is 340 ?

When you hit a current limit, how long does the coil shut down or
timeout?  Do you turn back on "instantly" when the current drops or
do you put it to sleep for say 1/2 second ?

As you know I am up to something and these issues popped up.
:-))  Thanks so much for sharing such great info!!

Cheers,

         Terry