On 25 Jun 2008 07:05:28 GMT, wrote:

In alt.engineering.electrical Paul M. Eldridge wrote:
| On 24 Jun 2008 17:20:49 GMT, wrote:
|
|| Hi Phil,
||
|| Alternatively, if you don't require that much light, you could simply
|| opt for a halogen lamp of a lesser wattage; e.g., a 40-watt Halogen?
|| ES provides the same amount of light as a conventional 60-watt
|| incandescent and lasts up to four times longer.
||
|| If you're still contemplating a low-voltage solution, Philip's IRC
|| MR16 are some of the best available.
||
|| See:
|| http://www.nam.lighting.philips.com/...pdf/p-5758.pdf
|
|5000 hours? Not all that good. Half will be burned out in 3 years of
|regular use (about 5 hours a day).
|
|
| Hi Phil,
|
| In the context of a regular A19 incandescent lamp with a nominal life
| of 750 hours to 1,500 hours, 5,000 hours strikes me as pretty good
| (since our original conversation pertained to standard household
| incandescents, I limited our options to incandescent and halogen light
| sources).

If the ordinary bulb ratings are only that (I really haven't looked in
ages, since I rarely need to buy them), then the numbers are different.
What I read in the referenced PDF was that these 5000 hour ratings is a
50% remaining rate. That's NOT what I see for regular incandescent
bulbs at 750 hours. Oddly enough, the bulbs that seem to burn out the
most are the ones in various table lamps subject to lots of vibration.
All the bulbs in all the hanging lamps and all the ceiling cans have not
burned out in the 5 years I've been in this house (that my mother had
built and my father now owns). Most of them are on all evening.

Hi Phil,

As with the halogens I identified above, incandescent lamp life is
based on the same 50 per cent rule -- that is an industry-wide
standard. For a graphical representation of this, see page 2 of:

http://www.sylvania.com/content/disp...x?id=003694068


| If long life is important, some of the new Philips T8s fluorescents
| have a rated service life of up to 46,000 hours but, then, as you
| indicated in another thread you refuse to use linear fluorescents in
| your home due to potential concerns related to Hg. On that basis, I
| presume we can rule out metal halide as well.

That's not my primary concern. It is a concern, and one that _may_ limit
my use of them. My primary concern is the poor spectrum (not the color) of
every fluorescent light I have ever seen. What I am referring to is that
the spectrum is not as uniformly continuous as incandescent. These are
therefore ruled out for critical task lighting areas (especially kitchen
and shop).


Sorry for my confusion. When you said "What about long tube
fluorescent lights that I also refuse to put in my home for the same
reason?" in relation to our other discussion pertaining to Hg, I
understood the word "refuse" to be an absolute.

If your primary concern is good light quality, there are fluorescent
lamps with a very high CRI such as the Philips TL930 (95 CRI) and
TL950 (98 CRI), but if you require something better than that, it's
probably best to stick with an incandescent or halogen source. And if
you're concerned your access to these lamps may be restricted at some
future date, you can always stock up on whatever you use now as a
precaution.

Cheers,
Paul