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Posted by RickH on September 18, 2007, 12:52 pm
> RickH wrote:
> > On Sep 18, 9:18 am, "dan" <> wrote:
>
> >>I posted a message earlier about light bulbs in my kitchen failing
> >>prematurely (lasting roughly 1 month). I received some good suggestions
> >>but did not find anything. Since then, I have paid particular attention
> >>to the lights (there are two on the same switch). When I turn them on,
> >>I have noticed a slight delay for the second bulb to light up. Could
> >>this be the issue? I would think both would instantaneously light up at
> >>the same time. I have not checked the connections, but will do so this
> >>weekend.
>
> >>--
>
> > I assume you switched bulb brands a few times to determine it's not
> > just a batch of bad bulbs. If you switch the two bulbs, does the
> > delay problem follow the same bulb? Are they ceiling cans? If so,
> > the thermal switch might be causing a delay due to carboned contacts.
> > Need more info. Temperature change is the hardist thing on a bulb,
> > thats why bulbs dont last long outdoors, especially in winter. Slow
> > start dimmers can extend bulb life a little.
>
> Rick, can you offer a cite confirming that temperature change is the
> hardest thing on a bulb.
>
> I'd think that given the huge difference between ambient temperatures
> and the bulb filament's white hot operating temperature less than a
> hundred degree swing in its starting temperature wouldn't mean diddly.
>
> Do automobile light bulbs fail more frequently in Minnesota than in
> California? I think not.
>
> Did you maybe mean to say that it's the outside weather conditions which
> cause bulb failures, stemming from moisture induced corrosion of sockets
> and bulb bases, which can cause all sorts of bulb failures?
>
> Jeff
>
> --
> Jeffry Wisnia
> (W1BSV + Brass Rat '57 EE)
> The speed of light is 1.8*10^12 furlongs per fortnight.- Hide quoted text -
>
> - Show quoted text -
By temperature change I mean sudden temp change, the sudden in rush
current to a cold filament going hot causes it to flex and eventually
break. Slow start dimmers bring the filament to temperature slowly
and avoid some of the sudden flex and resulting metal fatigue. For a
cite I would have to google around, but google for how slow start
dimmers help bulb life and that will probably explain more, I read it
myself years ago. My outdoor bulbs never lasted long, so I started
using CFL's outdoors in the carriage lights.
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