Arfa Daily wrote:
>
> "Baron" <baron.nospam@[EMAIL PROTECTED]
> wrote in message
> news:g4lfhd$75u$1@[EMAIL PROTECTED]
>> Arfa Daily Inscribed thus:
>>
>>> For twenty odd years, I have had the same Terry's Anglepoise bench
>>> lamp in service. I have always used perfectly normal 60 watt
>>> incandescent lamps in it, without any problem at all. Although the
>>> metal shade used to get quite warm, it was never enough to actually
>>> burn you when your forehead accidentally connected with it.
>>>
>>> Recently, the light bulbs I've been seeing and buying, seem to have
>>> reduced in size from the old 'tennis ball' size, to something closer
>>> to a snooker or pool ball (but not as small as the established 'golf
>>> ball' types often used in multibranch ceiling lights and light / fan
>>> fittings.)
>>>
>>> I have noticed that these new smaller bulbs run a whole quantum leap
>>> hotter than the older larger size, and they hot up the shade on the
>>> bench light until it is unbearably hot to touch. Today, I left the
>>> workshop for a while, and when I came back, the air was full of that
>>> 'fishy' sort of smell you get when something like a wall socket or
>>> the plug that's in it, is burning. A hunt around for the source,
>>> brought me to the bench lamp, which was still alight. When I moved
>>> it, it went off. When it had cooled down a bit, I took the bulb out
>>> (a UK bi-pad bayonet cap rather than a U.S. edison screw type) and I
>>> was horrified to see that one of the solder pads had just about
>>> burnt away completely, and the black insulation material in the base
>>> had started to burn as well. Fortunately, the brass lampholder was
>>> undamaged.
>>
>> Don't count on the lampholder being undamaged ! The springs in the
>> holder that apply pressure to the contact pads on the bulb, weaken
>> with
>> both age and heat. It would be wise to replace the lamp holder.
>>
>>> So, has anyone else noticed how hot these smaller bulbs run ? Are we
>>> talking dangerous here if they are used in any fitting where they
>>> hang downwards ? Any suggestions as to why there is such a large
>>> increase in temperature ? Yes, I can see that the glass envelope is
>>> closer to the filament, and that it has somewhat less surface area
>>> to radiate the heat away from, but I'm not sure that either of those
>>> are enough to account for just how much hotter they seem to run. And
>>> why had one pad burnt away?Anything to do with the solder being
>>> lead-free and less malleable than before, reducing the spring loaded
>>> contact area maybe ?
>>
>> Yes the smaller glass envelope does increase the heat considerably !
>> The bulb produces a little more light as well. I don't know that
>> being lead free makes a lot of difference, the heat sure does though
>> !
>>
>>> A bit worrying as I'm sure that there will be many situations where
>>> a fitting that has previously been quite happy with a 60 watt bulb
>>> in it, will now overheat, with possibly catastrophic consequences
>>> ...
>>>
>>> Arfa
>>
>> Yes I agree, overheating is a problem. I enlarged the vent holes on
>> my
>> desk lamp for that reason. I used a nibbling tool that I bought at
>> Radio Shack when I was in the USA a few years ago.
>>
>> --
>> Best Reagrds:
>> Baron.
>
> The lampholder is ok. Oddly enough, I renewed the cable to the lamp a
> few weeks ago, as it had gone intermittent at one of the bend loops,
Yes ! The middle one. The original cable was fabric woven sheath over
rubber. I replaced it with "electric iron" cable but that didn't last
as long as the original one. I've now got a modern plastic insulated
cable in there. Its much thinner and more flexible. I used cambric
spaghetti over the wires at the bulb holder end just in case the heat
damaged the plastic insulation.
> and as the holder was original, and looking a little worse for wear, I
> put in a new one, and a new pressel switch as well, which had failed
> and been bypassed
> long ago ... :-)
>
> Arfa
That little push on push off switch went a very long time ago ! There
is just the hole now, adding to the ventilation !
--
Best Regards:
Baron.
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