Terry's DRSSTC - 6000 BPS >:o)

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Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi All,

By simply changing the controller program (took all day...), I can now run 
at over 6000 BPS >:D  Hey! it's just electronics ;o))

With the list down today (odd "power surge" Chip says ;-))) I was trading 
E-mails with Steve Ward so I will past them together here...

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> How does the coil run at 5000bps?  And have you cranked it up yet? :-)))

It takes "very little" T1 to get long streamers!!!  I think they are right 
about a lot of energy / time, but it seems to make longer streamers than 
expected to me.  Have not studied that yet since just working to get the 
BPS rate up...  The thing does not have time to ring down so the effect 
where the streamers get big and small periodically with small changes in 
BPS is really pronounced.  It sounds like a hammer hitting a steel 
spike.  Sort of a "Tink, Tink, Tink,..." sound.  T1 is only about 30uS but 
it still hits a foot with 25 Reps / T4.  The sparks look like they would 
kill!!!  I stopped to redo the program and then got into all this timing 
stuff.  I use the new timing stuff now and it should be vastly better for 
programming!!

http://drsstc.com/~terrell/notes/DRSSTC-Timing-Chart-01.gif

Going to reprogram and verify the controller now...  I suppose I should 
worry about the stress on the IGBTs, but indoors at 30uS for T1 should not 
be a problem.

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Hi Again Steve,

Now I can go just over 6000 BPS >:)))  The microcontroller needs 125uS to 
go from line (on) to line (off) which is the limit.  The next controller 
might need the "Rabbit" type that rips at 40MHz and has 500K of memories 
(it can play wave audio files ;-))  But the little stamp is doing very well!!

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.  It definitely has a strong long and 
sort streamer affect with just a small change in BPS still.  I had to keep 
lowering the T1 time to keep the streamers at a sane length!!

The BPS rate is higher than I apparently can hear.  It just started to turn 
into sort of a "puff" sound at near 6000.

The streamers seemed to get sort of a sward like appearance to them like a 
tube coil has.  But unlike a tube coil, these streamers have a lot more 
power behind them!!  (or they would if I would crank it up ;-))  I worry 
about where the IGBT load is at.  The current should be low and the heating 
should be low...  I don't have a scope on it yet since the antenna are not 
at a safe distance now if something were to go wrong (I can easily fix 
that...).  But I wonder what the fast thermal heat on the IGBT is like 
during a burst.  It might be just fine, but I am not sure...

Super high BPS operation seems super cool!  We think of the energy in a 
single bang vs streamer length.  Now maybe we can think of streamer length 
in 25 bangs all adding "power"!!  The streamer length at 6000 BPS (25 
repetitions) is well over a foot.  If I turn down just the BPS leaving T1 
the same, the length is like 1 inch at 500 BPS!!  SQRT(25) is 5 so the 
length seems greater than expected from just adding repetitions!!

The little microcontroller's timing is just about "perfect".  I wonder if 
like a 555 timer setup would be good enough not to drift or if drift is 
even critical?  I suppose I could hard program "jitter" into the thing....

Many Wild and Wonderful things at high BPS!!  I suppose maybe we should 
think of a new Tesla coil "class of operation" now since things are 
dramatically different up there....

Well the snow has stopped and hopefully it will dry fast...  I will retool 
to get the scopes in there...  The 6000 BPS is not bad but, the 3000 really 
grinds the nerves!!  Probably good to shoot for supersonic BPS rates to 
save one's mind!!

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Hi Again Steve,

I took some scope pictures.  This is my DRSSTC running at "only" 2940 BPS 
;-)  There are all kinds of harmonics up there but this one was most 
interesting:

http://drsstc.com/~terrell/pictures/2940BPS-01.gif

http://drsstc.com/~terrell/pictures/2940BPS-02.gif

The first three pulses die down since the previous pulse ringdown is out of 
sync with it.  But on the fourth pulse they sync up again and a nice power 
burst is produced.  One can hear the different tones from these harmonics.

Here is another odd one:

http://drsstc.com/~terrell/pictures/2940BPS-03.gif

The best sparks are when they all seem to stay in sync through the burst!!

http://drsstc.com/~terrell/pictures/2940BPS-04.gif

The difference in spark length between in sync and out of sync is very 
dramatic!!  It is almost like the out of sync situation "poison's" the 
streamers!

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Cheers,

        Terry