Weird Bulb

[Chaos Master]

Dave Cole seems to have posted this:

I have seen dozens of examples of 60-100 watt severe-service bulbs used in
'drop light' portable work light fixtures fall to the floor and suddenly get
much brighter for 5-30 minutes, then 'flash' out. I assume they are either
arcing, oxygen getting in and burning the filiment, or the filiment shorts
(literally) to itself. New bulbs won't do this; only ones used for several
hours. I guess I ought to do a postmortem on one to be sure.
HTH

I recently had this here at home... accidentally hit a lamp and it became much
brighter. After a while it burned.
I guess it's a short.

Chaos.
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Chaos MasterŽ | "I'm going under,
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---------------------. -- Evanescence, "Going Under"

 

[Don Klipstein]

In article <MPG.1b14c37f2dcb16cd9899a8@130.133.1.4>, Chaos Master wrote:

Dave Cole seems to have posted this:
I have seen dozens of examples of 60-100 watt severe-service bulbs
used in 'drop light' portable work light fixtures fall to the floor and
suddenly get much brighter for 5-30 minutes, then 'flash' out. I
assume they are either arcing, oxygen getting in and burning the
filiment, or the filiment shorts (literally) to itself. New bulbs
won't do this; only ones used for several hours. I guess I ought to do
a postmortem on one to be sure.

I recently had this here at home... accidentally hit a lamp and it
became much brighter. After a while it burned. I guess it's a short.

I have caused incandescents to get part of their filaments shorted by
tapping them hard and by dropping them a short distance while operating
them. This mainly happened to me with the V-shaped 1-support filament and
the compact multisupported filament style in nightlight bulbs. However, I
can see that some other filament styles, especially the unsupported
coiled-coil ones about an inch (25 mm) long, can get partially shorted if
they suffer the "right" jarring when in operation.

- Don Klipstein (don@misty.com)