In reply to Stephen A. Lawrence's message of Mon, 01 Oct 2007 13:49:42 -0400: Hi, [snip] >I've personally heard of two cases in which an ordinary incandescent >bulb failed by exploding (glass all over). Both were perfectly innocent >applications; one was a reading lamp over a bed, the other was a Luxo >lamp in an office. Didn't happen to witness either one. From >descriptions of the events, though, I understand that both were >functioning normally at the time, and what's more, neither exploded on >turn-on -- both bulbs burst after the lamp had been lit for some time. > >I heard more details on the Luxo lamp incident: It was stationary and >undisturbed at the time, when it suddenly sprayed glass all over a >keyboard which was beneath it. > >Dunno what made them let go like that, but it certainly was something a >little stronger than the usual "arc which vaporizes the filament" which >causes the blue flash and the "pop" sound when a filament breaks during >one of the AC peaks. (Filament breaks at a zero crossing => there won't >be an arc, and there won't be a blue flash, and there won't be a "pop", >of course.) [snip] My guess would be that in these cases the gas seal weakened enough to admit air, which suddenly oxidized the glowing filament. Usually the filament gives out before the seal weakens to that extent, but occasionally, you may get a combination of a strong filament with a weak seal. Regards,
Robin van Spaandonk The shrub is a plant.
