Quote:
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Originally Posted by Dave
asalcedo wrote:
Lars Wrote:
Here in the UK many of the desk lamps I can buy nowadays take a bulb
with an Ediscon Screw fitting. Also many wall lights for outdoor use
(sometimes with a PIR detector) take an ES fitting bulb.
Until recently all I ever needed for a general purpose light bulb was
a bayonet fitting. Now ES fittings seem to be appearing!
Pictures: http://www.bltdirect.co.uk/base.htm
Is there a particular advantage of the ES fitting over the bayonet
fitting in these sorts of applications?
There is one situation where an ES fitting is clearly superior: Bulbs
subject to shocks and vibrations, like in a handheld inspection lamp.
The wobble of the BC fitting added to the shocks and vibrations will
reduce the life of the bulb to only a few days, if at all. With ES
fitting the bulb is more securely fastened to the lamp and will last
much longer.
But doesn't the fact that the bulb is so rigidly fixed add to its failure?
I would have thought that the wobble, you describe, would dampen the stress.
Dave |
I understand your point. The fact though is that the wobble is more like a free rotation, like a pendulum, rather than a damper.
My thinking about it goes like this: even if you rest the inspection lamp (bulb) carefully horizontally, just the weight of the bulb will make it swing within the BC fitting. If the bulb was swung on the other side this translates into a meaningful impact.
Let us say that there is no rotational friction in the bayonet, in this case, the tip of the bulb falls (rotates) with close to a 1g aceleration.
When you rest the inspection lamp in normal working conditions you don't drop it, perhaps 0.3g deceleration. Thus a BC bulb can get 1.3 deceleration versus only 0.3g for a ES bulb.