Re: electrolytic capacitors/homemade capacitors

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Christopher Boden by way of Terry Fritz <twftesla-at-qwest-dot-net>" <chrisboden-at-hotmail-dot-com>

Details...well, Thumper was designed with help of Cornell-Dubilier's head of 
R&D as a demonstration/research piece for the Group. It's a modular design 
and still in the Alpha phase with completeion pending our having the new lab 
in a few weeks and space/tools to complete it.

Construction is simple, banks of 20 caps (4 rows of 5) wired in paralell. 
banks can be connected in any combination of series/paralell and currently 
we are using 4AWG for cap to cap connections and 500kcmil for the main 
rails. The finished design will consist of 216 caps (we have 250 in stock) 
using 1/4"x1/2" Cu bar for cap-to-cap connections and 6"x1/2" Cu bar for the 
main rails.

Charging is through the CB-1 cabinet, variac controlled, current limited, up 
to 450VDC and charging time takes under a minute.

Discharge is though whatever we are using that day, usually a simple 
pop-can, but we have used work coils and other things (including a 486 
motherboard :)) for various demos. We have crushed cans with it, launched 
hard-drive rings *through* the ceiling (and roof), and turned several pop 
cans into various states of solid/vapor, sometimes leaving only a few grams 
of metal left at all.

Discharge is done through a simple crowbar arrangement, no diode, etc, just 
the switch, the ringdown is torture on the caps but we've never had one 
fail. Thumper has about 150 bangs on it so far.

Currently we are working on encasing the array in 1.25" thick Lexan to make 
it safe to demo in front of the public, just in case one of the caps let's 
go catastrophicly, since it would immediately become a grenade. The 
discharge chamber will be made of a large, reinforced, steel box.

Thumper is one of 4 main cap-discharge demonstrations of the Group, they 
are.....

Thumper: a large DC cap bank, 450VDC.

Stomper: Can crusher/ coin shrinker at ~15kVDC*

Groucho: 150kVDC Marx bank using 100 15kV CD caps in oil. This can be seen 
at 
http://www.thegeekgroup-dot-org/Images/2002Winterthon%20demos/Demos/pages/Thon03
-23-02%20012_jpg.htm 
and is already finished.

Harpo: A 1.5MVDC Marx bank for the Avalon facility.*

*=is waiting on caps to be delivered from Frisco where they have been 
collecting dust for over a year while we make arrangements to get them here. 
Just this past month we finally solved this problem and have a member who 
lives in CA and attends college nearby, he will be bringing them back this 
summer! :) Stomper should be finished for the Winter-2003 Teslathon.







Christopher "Duck" Boden Geek#1
President / C.E.O. / Alpha Geek
The Geek Group
www.thegeekgroup-dot-org
Because the Geek shall inherit the Earth!

>Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>" 
><evp-at-pacbell-dot-net>
>	More details, please!  I've used 12 of those in parallel feeding a
>rather large EI core wound with big wire to run a magnet charger which
>will almost magnetizer a matchstick.  Learned the hard way that it was
>necessary to put a very (VERY!) high-current diode across the coil to
>keep from blowing up the capacitors with the reverse voltage which has
>to flow.  I use a big 28 volt contactor to switch the circuit, and
>haven't had its contacts weld after about 200 or so operations.
>
>Ed
>
>
>


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