I can agree with the first part of this. I'm using 2 Westinghouse TA20 SCRs in series to discharge a 12 milli Farad capactance bank into an 88milli Henry coil. The bank is charged to 5750 volts & peak discharge current is 1600 Amps. No heatsink is needed there & the current flows for much longer. (peak current reached in 50mS) Rep rates are low though as the coil needs about an hour to cool after a shot. If I'm not mistaken, one of the problems with using lots of SCRs together is triggering. If they don't all fire at exactly the same time bad things happen. Joe > -----Original Message----- > From: piclist-bounces@mit.edu > [mailto:piclist-bounces@mit.edu] On Behalf Of Morgan Olsson > Sent: 14 December 2005 12:47 > To: Microcontroller discussion list - Public. > Subject: Re: [EE] Solid state can crusher > > > > I think this could be made a easier. > > 1) Why the heatsink at all? During theese microsecond pulses > there is no chance at all that the heat from die propagate > even to the surface of th eSCR package. Heatsink is only > relevant if diong discharges short after each other in time. > And even then not very hot; take average current (easiest to > measute as capacitor bank charge current) times SCR > conducting voltage (max 2V?) Not many watts. > > 2) Why one expensive SCR? Much easier to get parts if > desinged using many parallel circuits of {discharge cap, SCR, > coil winding}. So that the coil is made up of twenty > intertwined conductors, each connected to in one end to an > own SCR; in the eother to an own capacitor. Just make sure > everythng is parallel/symmetrical and fire all triac firmly > at the same time by another firing SCR. > > Maybe a hefty coil could be made using wound enameled copper > wires, and clad with epoxy and glass fibre... And inner and > outer spliter protection of polycarbonate tube. > > That way we can build heftier things using cheaper parts. > (although the coil is a bit harder to make. (I would not try > building such thing anyway...) /Morgan -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist