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Posted by Jeff Wisnia on September 19, 2007, 6:25 pm
willshak wrote:
> on 9/19/2007 3:28 PM Jeff Wisnia said the following:
>
>> willshak wrote:
>>
>>> on 9/18/2007 2:22 PM Jeff Wisnia said the following:
>>>
>>>> RickH wrote:
>>>>
>>>>>
>>>>>> 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.
>>>>
>>>>
>>>>
>>>> Thanks, the inrush current part I agree with. I mistakenly thought
>>>> you were referring to outdoor ambient temperature changes as
>>>> contrasted with the generally smaller range of indoor temperature
>>>> changes.
>>>>
>>>>
>>>>> 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.
>>>>
>>>>
>>>>
>>>> Ans did I. The lights on either side of our front door had three
>>>> candelabra based flame shaped bulbs in each of them when we bought
>>>> the place. I don't think we could go for more than a month without
>>>> one of those six bulbs burning out, and it required a stepladder and
>>>> some serious arm twisting to replace a bulb, usually accompanied by
>>>> my cussing when I dropped one of the little decorative nuts which
>>>> held the tops on those fixtures.
>>>>
>>>> Shortly after CFs became available I replaced the three sockets in
>>>> each of those fixtures with a single edison base one and stuck in
>>>> CFs. That was probably close to ten years ago now ant the original
>>>> CFs are still going strone here in Red Sox Nation.
>>>>
>>>> ***********
>>>>
>>>> I've seen "bulb life extenders" for incandescents which were just
>>>> NTC (negative temperature coefficient) thermistors housed in a
>>>> housing you could stick into a socket before screwing the bulb in.
>>>>
>>>> Don Klipstein's work describes that application thusly:
>>>>
>>>> http://members.misty.com/don/bulb1.html#ss
>>>>
>>>> Jeff
>>>>
>>> One of the complaints against using CFLs is that they are slow to
>>> start. The extender would cause the same complaints for an
>>> incandescent as a CFL, but using more energy than a CFL.
>>>
>>
>> The "extenders" I've see just slow the start by a second or two, no
>> where near as long as the CFLs in my outside front door lights take to
>> come up when it's cold outside.
>>
>> But you are correct on the energy usage.
>>
>> I can't wait for LED bulbs to get down to a reasonable price. From
>> what I've read they'll last nearly forever and won't be a serious
>> hazardous waste. LEDs seem to have already "taken over" in many of of
>> the traffic signals around here.
>>
>> Jeff
>>
> Yes, and the auto industry has been using them in taillights, but
> there's about 20 LEDs in each lamp. LEDs have to be used in large groups
> to be useful enough for home lighting. The light from one LED bulb is
> little better than a candle.
>
Yep, here's a place which sells screw-in LED bulbs, but it presently
costs nearly $70 to buy one which puts out about the same number of
lumens as a 50 watt incandescent, but consumes less than 10 watts.
When the price gets down to around $10 for an LED bulb comparable to a
75 watt incandescent you can bet I'll be standing in line to buy some.
Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.
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