Re: Terry's DRSSTC - 6000 BPS >:o)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Gerry,

At 11:55 PM 5/1/2005, you wrote:
> Hi Terry,
>
> > Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>
> >
> > It seems that each bang just "adds" to the next.  I don't mean like a 
> > streamer follows the path from the last bang.  It is like the T1 time is 
> > just stretched out.  The T2 times seem to get lost and the streamer 
> > builds like it was just one long T1 time.
>
> What is the advantage in 25 bangs in a burst vs having one bang where T1 
> is 25 times longer.

After about 15 bangs, the sparks just get thicker and hotter rather than 
longer.  In my case, I am thinking having all the interruptions in there is 
helping streamer length.  If it were true CW, the streamers would only be 
like a 5 inch brush...   The interruptions seem to be the key to long 
streamer length.

> I would think the thermal time constant is longer than a burst 
> period.  Could it be the smoothing effects that would have on the main bus 
> ripple.

You can tell if the buss is being loaded down from the primary 
current.  Right now, at 100 amps peak, that is not an issue.

> Maybe there is a current issue, if so, how long can T1 be for a single 
> shot before overcurrent is an issue???

The current will "top out" at about 200 amps with a streamer load when the 
input power and streamer power are equal.  But higher BPS rates make the 
total power higher.

> I guess I'm thinking if the IGBTs and controller could take it, what would 
> happen if T1 were like infinite??

"Just" a CW coil...



> > I had to keep lowering the T1 time to keep the streamers at a sane length!!
>
> When you vary something else??

As I raised BPS.  I fixed the program a little so that works smoother now.



> > I worry about where the IGBT load is at.  The current should be low and 
> > the heating should be low...
>
> What is the concern if the IGBT's are over current and thermal protected???

They could heat "very fast" blow before the temp sensor out on the heat 
sink sees it.


> BTW, it looks like you have 26 bangs per burst by looking at the scope 
> pictures (might be an issue when you start doing real streamer experiments)

Really????  Darn software...  Yep your right ;-))  I have one too many 
firing statements in the program...

Cheers,

        Terry


> Gerry R