Warning! High voltage
capacitors are ridiculously dangerous things. They can store enough energy to kill you
New! Dec 2004 - high-speed camera footage of can crushing, CD Smashing and other destruct-o-tron mayhem
A long time after having lots of fun fun blowing stuff up with the high-energy capacitors from the Surge Generator, I came across a few more caps, which with the originals, makes up a total of 220uF at 5KV (some of the newer caps had a lower voltage rating than the original 6KV ones). I decided to build them into a box with a charging supply to make the setup slightly safer and easier to use. I had a few microwave oven transformers (MOTs) lying around, and a pair of these in series provided an ideal charging supply, producing slightly over 5KV after full-wave rectification.
Internal views (Left) capacitors. (Right) : Green cylinders bottom-left are safety discharge resistors - these are connected across the caps when the switch closes, to ensure a rapid discharge if the 'victim' goes open-circuit during the discharge. Large blue cylinder (centre) is one of two 100R resistors, used in parallel to limit the mains current into the transformers to about 5 amps - these get HOT!. On the right is the stack of 2 Microwave Oven transformers, wired in series and rectified by the rectifiers on the right to produce the charge supply. A relay on top switches power to the transformers, switching being arranged so that the transformers can't be turned on unless the discharge switch is open.
>Wired remote control - standing well back is a good idea.. Button holds discharge switch open, and momentary keyswitch controls charging supply.
(Left) An early failure - at these currents, things you normally think of as pretty solid, like solder tags, start turning into fuses...
(Right) Like lasers, these things need
appropriate warning signs...
OK, time for some destruction....
The obligitory aluminium can, wound with about 5 turns of heavy wire and zapped at about 3KV.
(Right) Platter fom 2.5 inch hard disk, placed above coil and held down so it couldn't jump off.
(Left) Before : A short length of 22mm copper pipe.
(Right) After : A coil of 2.5mm2 solid-core copper wire was wound
round, and zapped at about 4KV. The pipe is seriously crumpled, and the wire melted open,
splitting much of the insulation.
< A 1mm aluminium plate placed on top of the 3" can-crushing coil, then clamped between 2 pieces of wood, with a dowel on one side - the plate gets folded round the dowel as it is forced away from the coil!
> A ring of 1mm aluminium cut from an old laser printer drum, originally 40mm dia. 4KV
I didn't think the power would be sufficient for coin shrinking, but I found some Japanese 1 Yen coins, which are made of aluminium. One of these shrank very nicely! The 'ripples' on the surface come from the grain of the wooden dowel used to hold the coin inside the coil. 4.5KV, about 2200 Joules.
> What was left after the coil was fired.... The yellow is part of a plastic storage bin that was placed over the coil in a futule attempt to catch the debris - it shattered!
>After.. This is what I call FireWire! - holes blown in the top of the
large chip and also the voltage regulator (bottom). The PCB has de-laminated as tracks on
the inner layers vaporised..!
< Exploding a
few inches of steel guitar wire. Steel wire is usually more spectacular than copper, as it
both burns and vaporises!
> A hard disc platter spacer ring - 3 x 4mm cross-section aluminium
See also the Surge Generator page for more info on electromagnetic crushing, and exploding stuff.
Wear & Tear
Left is how the contacts started off. The two right-hand pics show the state of them when I recently took the breaker apart to replace some frayed wiring...