About the same time frame I recall an instance where an electrolytic about the same size "poofed" in the night. There was only one operator on duty and his reaction was to get out and call security because the only symptom was that a door on a tape control unit sprang open with no one around. Of course there was the crash of the door flinging open. As it worked it was one of a dozen or so caps in parallel and the system never hiccupped! John Ferrell http://DixieNC.US ----- Original Message ----- From: "Howard Winter" To: "Microcontroller discussion list - Public." Sent: Sunday, December 25, 2005 9:13 AM Subject: Re: [EE]: Polarity of electronic capacitor when using both positiveand negative voltages > On 12/23/05, Spehro Pefhany wrote: >> At 11:00 AM 12/23/2005 -0500, you wrote: >> > > >> > > >> > > In my experience, ordinary electrolytics aren't as dramatic as >> > > tantalums when they go. The vent just opens and they sneeze out the >> > > electrolyte. A fizzle, not a bang. >> > >> > >> >Yeah, they've improved them.. They used to throw aluminum case and guts >> >all >> >over the place if properly abused. >> >> I think only large ones have a vent- the small ones will probably still >> blow up good. > > In the 70's we had a computer room (remember them? :-) which had automatic > CO2 extinguishing equipment, and > one night a large capacitor (think bean-can size) exploded, and took out > the terminal rack it was powering, > frightening the operators, and creating a small cloud of smoke. Everyone > left the room except the shift > leader who rang the operations manager to tell him bout it. A minute into > the conversation it went something > like: "What's that bell ringing?" "I've no idea, perhaps..." > "WHOOOOOOOOSH! Thump, Crash!" > > The bell was the fire system saying that it had detected smoke and was > about to trip the extinguishing system. > The Whoosh was the room being filled with CO2 *really* fast, the thump and > crash was the operator dropping the > phone, vaulting the handrail that divided off the ramp from the raised > floor down to the door, plus opening > the door with his body's momentum! :-) > > There was no actual fire, just the smoke from the demised cap, but > apparently the sprayed electrolyte and can > shrapnel was enough to write off the 6U-high PSU and some of the equipment > above it, so that plus the lost > computer time and refilling 8 CO2 tanks made it a very expensive > capacitor! > > Those were the days... > > Merry Christmas! > > > Howard Winter > St.Albans, England > > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist