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PIRANHA Update

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Terry Fritz

Tue Feb 13 2007, 10:05PM

Registered Member #393 Joined: Tue Apr 18 2006, 12:30AM
Location:
Posts: 297

Update:

I updated the site and had to break most of the links in this post in the process

Hopefully the information will now be found here:

Contact me if you need more info till I get it all back together.

==============================

Hi,

I wrote up this update about the PIRANHA for a guy that wanted to make a little one and just thought I would mention it here too...

===========
SISG's and PIRANHA class coils can run at any power level depending on the number of SISG sections used. It is about 6 inches of arc multiplied by the number of sections minus the toroid radius. So one of Mark's SISG boards would be fine for say an 18 inch arc coil. You would need a small variac or one of the solid state variac boards Dr. R. mentions for control. The basics of the SISG are here:

I never got further on "my" solid state variac thing. I "think" DC's needs a charging choke where mine would not.

Most of the details are here:

There are actually "three" versions of the PIRANHA.

PIRANHA-I was the first demonstration coil:

It used a modified prototype 3 sections SISG experimental board:

It's a cool coil, but the giant resistor in it waists way too much power. Although it demonstrated and served as a prototype of the concepts, the PIRANHA-I electrical design is really very obsolete and I don't recommend it. The physical coil is fine. If it was not for historical value, I would replace the electronics with PIRANHA-II

PIRANHA-II uses the full PIRANHA charging system for very high efficiency and is what you want to use:

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 (although the vastly more complex DRSSTCs have more technology and "stuff", they don't work as well

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

*Dave has made the biggest sparks off a ball terminal with his coil:

PIRANHA-III is a dual MOT 120VAC 20 AMP (single circuit :p ) coil that would put out 8 foot arcs. Although designed, it has not been built yet. PIRANHA-II scares me bad enough at "1/2 power" already =:O)

Microwave parts can be bought new and at a great price from this place if you don't want to shop at the junk yard:

The higher wattage MOTs are best since they do not have as much loss and are fairly cheap at $55 to $65. Those 16kV 750mA AMI3347 diodes RULE!!

Note that PIRANHA primary drive circuits are EXTREMELY dangerous!!! There is "NO current limiting on the HV"!! Ballasting is done by "magic"*. Even pig systems are probably safer!! PIRANHA-II's primary circuits are totally enclosed and double insulated. It does not need cooling vents since it does not waist power.

*I was hoping Conner would figure it out :O)) But only the computer seems to know...

Cheers,

Terry

Finn Hammer

Thu Feb 15 2007, 07:45PM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

Terry Fritz wrote ...

Hi,

snip

With its ball terminal toroid (which works fine*) and PIRANHA-II electronics, it is probably one of the most advanced Tesla coils on Earth (although the vastly more complex DRSSTCs have more technology and "stuff", they don't work as well Finn's triggered single brick BRISG is a "stunningly" wonderful machine too!!

snip
Cheers,

Terry

Thank you for your kind words.

You are right, the DRSSTC is easy to understand but difficult to construct. The SISG is just the opposite. That`s why I had to design the BRISG: it is easily understood, and also easy to construct.

Cheers,

Finn Hammer

Terry Fritz

Thu Feb 15 2007, 10:44PM

Registered Member #393 Joined: Tue Apr 18 2006, 12:30AM
Location:
Posts: 297

Hi Finn,

It may also be much cheaper! The IGBTs I was using are about $18 each now. For PIRANHA-III that is almost $300 in IGBTs alone!! The Fairchild FGL40N120ANDTU looks like a promising alternative for about 1/2 the cost. But big bricks go on E-bay all the time for far less still... The high prices might be just due the the lead thing and last time buys... But IGBT costs are a big factor..

Cheers,

Terry

hvguy

Thu Mar 01 2007, 10:46AM

Registered Member #289 Joined: Mon Mar 06 2006, 10:45AM
Location: Conroe, TX
Posts: 154

Is there a schematic for this BRISG somewhere? Or is it just an SISG with a brck?

RickR

Thu Mar 01 2007, 11:43PM

Registered Member #93 Joined: Thu Feb 09 2006, 04:11PM
Location: Houston, Texas
Posts: 64

Hi Terry,

All the links for your Piranha-II information above seem to be broken. Is there a different path I should follow to get to the information? I'm really interested in your improvements over the Piranha-I design.

Thanks,

Rick

Terry Fritz

Fri Mar 02 2007, 05:00PM

Registered Member #393 Joined: Tue Apr 18 2006, 12:30AM
Location:
Posts: 297

Hi Rick,

Sorry for the broken links...

The site is being totally reworked to add more safety information and to make it more coherent.

In the mean time just PM me if you need more info...

The BRISG, is a single section super high current but low voltage SISG. Operation much like an OLTC. Finn knows more on this thread:

Cheers,

Terry

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