RE: Piranha II tuning (was: Re: Dual MOT plans - PIRANHA)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Mark Dunn" <mdunn@xxxxxxxxxxxx>


Dan:

The power supply for an SISG based coil(like Piranha) is a pulsed DC
type.  The matching of the power transformer to the tank capacitor is
required to set the break rate(BPS) for the coil system.

For example, if you have a very high impedence power transformer, then
the break rate will be low for a relatively small tank capacitor and
even lower as you increase the size of the cap.  This is because it will
take longer to charge the cap and thus more time before the SISG reaches
its threshold(firing) voltage.

With a low impedence power transformer, the break rate will be very high
and to bring it down you must increase the cap size.

Once you "match" the power supply and cap to get a reasonable break
rate, then you can tap the primary to get the Fres that matches your
secondary-toroid system.

You may recall from posts last summer that when my first SISG coil was
fired up, I had a break rate of ~1200 BPS.  I brought that down by
increasing the impedence of the MOT's(with modified shunts) and
increasing the size of the tank capacitor.

Hope this helps.

Mark

>Original poster: "Daniel Kline" <daniel_kline@xxxxxxxxxxx>

>Tesla list wrote:
>>Original poster: Terrell Fritz <terrellfone@xxxxxxxxxxxxxxxxxxxxxxx>

>>You would just change it to use "one" of Mark's boards and it would
>>use a lower input voltage and current.  All the component values are
>>the same but the caps probably don't need very high current ratings
>>for just one board.  With its ball terminal toroid (which works
>>fine*) and PIRANHA-II electronics, it is probably one of the most
>>advanced Tesla coils on Earth.

>Great information! The only thing I don't understand is how the
>tuning works...is the cap-bank frequency independent?

>What I think I would normally have to do is to consider my
>capacitance as a fixed value and design a matching primary, so that
>the cap/primary
>Fres would compliment my secondary's Fres. Since I'm only after 18"
>max, I wouldn't want to have a 3-foot-tall secondary, but rather
>something more proportional to the spark length. Is there room in the
>design for different primary/secondary configurations?


>>Finn's triggered single brick BRISG is a "stunningly" wonderful
>>machine
>>too!!

>Ack. I can't find a schematic for that.

>>Those 16kV 750mA  AMI3347 diodes RULE!!

>Right on :-)

>Thanks,
>Dan