This electrolytic capacitor bank 1.5 kJ has SCR (silicon controlled rectifier) switching to control peak currents of thousands of amps. Mostly to make big bangs but also to drive projectile devices such as a rail gun and coil gun.
“Continue reading” for more details and photos.Power is 1500 Joules at 4700 uF 800 V from 4 electrolytic capacitors rated at 4700 uf 400 V each.
The heavy duty SCR was one of 3 still functioning that I obtained from a 3 phase 400 A controller. They cost AUD$50 from a scrap yard. I have blown one of them into a very low impedance unloaded coilgun. They come with a solid heat sink and heavy gauge leads. The heat sink is not needed for this application. There is little transfer of heat with these single pulses of typically a few tens of milliseconds, however I don’t have the tools to remove them. The 4 capacitors are 4700 uF 400 V. The charging transformer from an ancient TV is bottom left with voltage doubler and relay. The SCR drive electronics and protection diodes are upper centre. The drive electronics come from Sam Barros’ site. It all fits with a bit of a squeeze in a lockable glass fronted aluminium case.
Ready to fire. The electrolytic capacitor bank is connected to heavy copper bus bars with 1 x 4 inch aluminium foil across them. Note that part of this flash is the 1500 joules and part is due to ignition of the aluminium as there is very little of it left. Aluminium is explosive when powdered and is used for flash/bang or stun grenades. Check this out for a really serious capacitor bank ( 3.2 MJ ).
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Stun grenades
Capacitor bank ( 3.2 MJ )
Photo Date: Jan 19, 2003