Re: PIRANHA - New Top Load Configuration

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Bart and Stan,

At 08:11 PM 11/3/2006, Bart wrote:
> Hi Terry,
>
> It's looking good! Tonight on the way back from dinner, I drove by a 
> house that had ball lights on a pillar in their yard. It reminded me 
> of your topload stack. There were 4 ball lights configured as your 
> topload and about the same size. What was different is that there 
> was a ball in the center of the 4 outer balls.
>
> Looking at the picture you showed where the corona is streaming off 
> the secondary is probably a good indication that a center disc laid 
> on top of the rods and about the inner diameter of the balls would 
> help eliminate that corona.

"Looking at it", the balls are probably too high.  I will cut the 
center rod down about 2 inches.  That should fix it.

I guess I sort of disagree about a center ring.  The field plots show 
the voltage stress in there to be very low:

http://drsstc.com/~piranha/PIRANHA/PIRANHA-2/newcoil-01.jpg

The shape of the corona looks like "toroid too high" to me.  I made 
it high at first since it is easier to cut the rod shorter than to 
"cut it longer" ;-)  To bad since the corona is really cool!!  It is 
very bright, pretty, and stable...  Very cool that the balls have no 
problem at all holding off at 300kV!!!  Perhaps six 6 inch balls 
might have been a good choice too...  The top dragon can be adjusted 
at will for a pretty break out point.  Taped on nails to the balls 
work good too...  There is a "little" mark left on the balls from the 
nail contact, but a zero problem there...  Those SS glazing balls are 
super tough!!!


> Great job with it all, it looks really nice. Glad to hear your going 
> to coat that secondary (the wrap just doesn't do it).

:-)

I added a 10 amp fast blow fuse incase "something goes wrong".  Even 
at full power, the thing only draws 10 amps at about 105 volts 
;-))  But if something shorts or goes wrong, a 10A fuse will pop like 
a flash cube probably limiting much damage ;-)

I got the guts finished off with the fuse and a big standoff to 
attach one primary lead.

http://drsstc.com/~piranha/PIRANHA/PIRANHA-2/PIRANHA-Const-011.JPG

The idea is to remove or install the top cover, the lid will be 
cracked open a few inches and I will reach in there with a nut driver 
to disconnect the massive primary leads.  the primary wire is pretty 
tough to bend around but once tuned it will never change...

http://drsstc.com/~piranha/PIRANHA/PIRANHA-2/PIRANHA-Const-012.JPG

I need to get some poly tubing to cover the down leads since the 
voltage there is a bit high for the wire insulation alone.  There is 
good clearance between the fan and all and the heatsinks and other HV 
parts.  The pictures don't show that well...

It is sort of "cool" that there is really no external cooling for the 
guts. The box has no cooling vents or anything. The fan just blows 
internal air over the heatsinks that dissipate 24W worst case. At 
full power, the heat load is around 250W. For short runs that is fine 
for the big box. All of the parts run practically "cold" now... It 
would need a small external fanned vent if it were going to run 24/7 
though ;-)  The base board is neat in that any changes like that are 
just a matter of changing the $2 piece of plywood around. I wondered 
if I should just not have the fan, but it is already "stuck" to the 
capacitor ;-)  The resistors are also finally on ceramic standoffs 
now.  The MMC is still the old underrated in current (prolly voltage 
too...) one, but I'll wait till it blows up to worry about switching 
it out :o))

The coil will be 'really' "silent" since the fan will be hard to hear 
in the box (it was very quiet anyway). Of course, the fully 
electronic "engine" make no noise other than some magneto 
constrictive clicking.

The coil goes from dead silent to full power at a chaotic ~~250 BPS 
"instantly" (like 1uS!!). It's sudden screaming start up is quite a 
"shock"!  It also "still has" 50% more length (2.25X more power) I 
have never used since it is indoors >:-))  The SISG sections are all 
still shorted to 600V :D

I was thinking of some sort of dark picture framing matt board to 
cover the top of the box.  Leather was also a thought but it might be 
too "floppy" unless I glued it down (maybe that super doubled sided 
carpet tape...). but the matt board could be very easily removed to 
show the guts...  The Weld-On acrylic cement has stuck the brackets 
on super hard!!!  I like that stuff!!  It is supposed to kill you 
instantly and give you cancer, but played with out of doors (Nitrile 
gloves and safety goggles ) it is zero problem.

It's really cool!!


BTW - Now that others are interested in the design, be VERY aware 
that the PIRANHA primary circuitry is VERY DANGEROUS!!!  There is NO 
ballast or current limiting for the MOT which pretty much directly 
connects and drives everything on the primary!!!  The 165nF caps hold 
4 joules at 7000V and can recharge at 500BPS!!!  It is an easy and 
simple design, but it packs a LOT of "serious killing power"!!!  They 
are "very different" that any other coils...

I have "buried" the primary stuff in the box and the primary coil is 
insulated and under 1/4 inch of plastic.  All the primary HV stuff is 
impossible to touch.  All the external metal is fully 
grounded...  Just don't get silly with these types of potentially 
"very deadly" coils!!!

Cheers,

        Terry