Rather dramatic incandescent bulb failure.

I just went to turn on a light. The bulb emitted a bright blue flash, and its glass envelope separated from the base, bounced off the rear enclosure of the television and fell to the wooden floor.

Scared the bejeezus out of me. The only redeeming feature was that the bulb didn't shatter.

After fifty years and a few, that's a new one on me.

Sylvia.

Reply to
Sylvia Else
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We've had a few of those, last one the bulb exploded and sent glass over three metres, the still flaming filament landed on a leather chair. The box it came in said "Quality Checked". Hope the new high efficiency ones don't go the same way.

Reply to
M Phillips

On Mon, 17 May 2010 00:08:13 +0930, "M Phillips" put finger to keyboard and composed:

The box passed all its tests.

- Franc Zabkar

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Reply to
Franc Zabkar

On Mon, 17 May 2010 00:24:59 +1000, Sylvia Else put finger to keyboard and composed:

I've had Mirabella bulbs that did that.

- Franc Zabkar

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Reply to
Franc Zabkar

Mine was an Osram.

I'm a bit surprised, indeed somewhat concerned, that the circuit breaker didn't trip. It's rated at 10A, but the individual lamp sockets won't be. I'm wondering how I can safely test it.

Sylvia.

Reply to
Sylvia Else

Anyone know what the typical failure mode of a compact fluorescent is? (I assume that's the intent of "high efficiency").

Sylvia.

Reply to
Sylvia Else

Classic ordinary light bulbs are fused, usually both leads to the filament have fuses fitted. If you still have the lamp you would see the fuses welded into the wires on the inside of the glass filament holder.

So your 10A circuit breaker would not ber expected to trip as the lamp's overcurrent was over way to soon to trip a thermal breaker.

As for the lamp bulb jumping out of the base, was it a very old lamp?

Lots of thermal cycles possibly weakened the adhesove to the base.

As to failure mode of CFLs, I been using CFLs for a couple decades, and ones I see fail simply go out, or fail to start. Recently a matched pair of supermarket CFLs in the same light fitting quit within days of each othjer -- so I took the glass out of that ceiliung fitting to let the replacements run cooler.

I think CFLs suffer from the heat buildup inside some types of fittings.

Grant.

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Reply to
Grant

In this instance, the power wires are intact from the filament, through the glass seal, and about halfway towards the base - then they vanish - both of them, at about the same point. I suppose the fuses could have been fitted there, explaining why the wires terminate abruptly. When whatever was there, be it ordinary wire, or fuse, evaporated, it would have increased the pressure in the space between the seal and the base, both through the evaporation, and heating of the air in there.

Well, falling out, given that this was in a typical lamp holder suspended from the ceiling.

No, it wasn't old at all.

Perhaps, though it was a living room light, so I wouldn't expect it to suffer high cycles before filament failure.

Sylvia.

Reply to
Sylvia Else

My halogen work light died today, it came on then flashed a few times, gave out a loud buzzing sound, finally one very bright flash and then died. It stayed mechanically in one piece though.

Reply to
keithr

**I've heard about capacitor failures. I've never experienced any. I've been using CFLs for about 8 years. I presently have a couple of dozen around the place. All are Philips branded lamps, except four PAR38 CFL floods (which don't get used very much). Some are used from as little as 10 mins per day, to more than 4-5 hours per day. The two failures I've had were:
  • Possum sat/fell/brushed against one in the garage.
  • I installed one into a portable 'touble light' and dropped it. A rock penetrated the glass.

I am uncertain if an incandescent would have survived or not. I'm betting a definite maybe.

I don't much care for the colour temperature of the cheap brands, nor, it seems, their reliability. I've found the Philips lamps to have a pleasing colour temperature and have, thus far, been utterly reliable.

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Trevor Wilson
www.rageaudio.com.au
Reply to
Trevor Wilson

I've tended to opt for the higher colour temperature variants. OK, they look rather blue in comparison with incandescents, but in reality they are just a better white. One gets used to them, as well as having things look blue when they are, rather than black.

Sylvia.

Reply to
Sylvia Else

Bad Caps are very common in many China made things around my place. Here pictures of one of a few CFLs that spit the dummy on me:

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Note that not only had the Cap a short but also the connections to the actual tube where more than dodgy.

Tony

Reply to
TonyS

I wonder who it was decided that four diodes were optional. Looks like three were simply ommited, and one was replaced by a link.

Sylvia.

Reply to
Sylvia Else

Well that's where the fuses were, I remember them as being encapsulated, but perhaps that's a feature on some brands only. This is something I explored a long time ago.

Yes, any electric fireworks usually gives at least a pop, sometimes a bang :) The fuse is only a section (about one cm or 1/2") of smaller gauge wire spot welded between the wire from the filament glass to the wire from the lamp base. Sometimes the fuse is encapsulated in a long glass envelope, I don't think your lamp had the encapsulated sort.

Funny, I visualised the lamp being closer to ground level, thinking it dropped a small distance. Dropping from the ceiling and no broken glass is more amazing.

Ah well, maybe the modern glues are less sticky? Long time since I saw an old globe go pop, CFLs fail without fanfare here.

Grant.

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Reply to
Grant

Would you like my Phillips CFL that failed to work from new then? I've had dozens fail, including a few Phillips and many other brands. In fact I've

*never* had one last as long as claimed yet! (and very few are in enclosed fittings either)

MrT.

Reply to
Mr.T

one the bulb exploded and sent glass over

box

n't

Usually the tube fails, I have checked dozens of dead ones over the past few years. (Connect a normal tube to the terminals and it will work.)

Havent seen any electronics failures, but in our case they all have been operated inside ventilated equipment cabinets, the base to the bottom.

Others have had other experiences however, judging by stories and pics on some forums, though may have been used in hot areas, or sealed fittings with nil ventilation. Under these circumstances, I see no reason to doubt these reports considering some of the crap electronics around, and the common failure of electrolytics in most applications.

I recall hearing years back about a mirabella brand bulb "exploding" at switch on. It might have been on a consumer affairs program (that one on ABC years back probably), a current affairs type program or similar.

No details were given of the exact failure other than "big bang and bulb flew out of socket" or similar.

Another warning I read of a long time back was the use of certain incandescent (maybe QH or back reflected varieties of floodlight bulbs used) in shop window displays. They could shatter when they failed, dumping red hot filament pieces over clothing or other flammable display items beneath, starting a fire.

Reply to
kreed

Stem fuses in many bulbs. designed for moments like these :)

Reply to
kreed

"kreed"

Usually the tube fails,

** Yep - the filament at one end burns out and typically leaves a dark mark on the glass.

This is a direct result of makers running the filaments very hot in an attempt to get the lamp to produce full light output quickly even when the ambient temp is close to 0 degrees C.

The other common failure is the glass tube cracking during handling as it is impossible to install or remove a CFL in many light fittings without holding onto the glass.

You don't get to see many failures that originate in the electronics because the other failure modes come first OR else the tube loses so much light output is it no longer usable.

IME lifespans for CFLs quoted on the packaging as being 10,000 or even

15,000 hours are purest fantasy.

..... Phil

Reply to
Phil Allison

Well, not actually from ceiling height, because it was suspended. But I suspect that television saved the day, because the bounce off the rear housing probably caused the bulb to turn over so that it landed on its stem (which would be much stronger) rather than on the fragile spherical envelope.

Sylvia

Reply to
Sylvia Else

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