Re: Season misconceptions in newspaper

[Brian Whatcott <betwys1@SBCGLOBAL.NET>]

> At 08:27 24/06/03 -0700, Roger Haar wrote:
> >...
> >         I have wondered if running  a halogen lamp very
> >dim would actually shorten its life because the
> >dissociation on the filament might be less
> >effective.

At 10:15 PM 6/24/2003 +0200, Mark Sylvester  responded:

> I can confirm that running on low voltage does drastically shorten the life
> of the lamp. To something like a few minutes in the case of the 12V halogen
> lamps we were using as variable light sources a while back.
>
> Another issue: there was a scare a while back about the combination of high
> temperature filament and quartz envelope resulting in the emission of
> significant levels of harmful UV. Has this been confirmed?
>
> Mark
> Mark Sylvester
> UWCAd
> Duino Trieste Italy


Talking about the distinct impact of voltage on life,
I see that another four pack of A-19 frosted incandescents
that Norma bought home, was billed as a 130 Volt pack
from Westinghouse.

I have a suspicion that there aren't many sources of 130 volts,
so the default data strip which shows
645 lumens, 60 watts, 5000 hours is not very helpful.

But on the side of the package is a table for 120 volt usage -
which looks remarkable:
485 lumens, 53 watts, 14000 hours (!).

This 4-pack cost us $1.49 plus 8% tax.
The luminous efficiency life product of 128,000 lumen.hours
per watt compares well with the  81,000 lumen.hours per watt
I found for the Phillips krypton fill traffic lamp bulb.
Using that rational merit parameter I mentioned earlier,
the  lumen. hours per watt.cent figure for the Westinghouse
130v Commercial pack  is 3180  @ 40 cents unit cost.

I take consolation in small bargains - and this seems to have
 been one. (Unless you talk to an accountant anyway: in that
quarter, the net present value of long life products can be
heavily discounted.)

Brian Whatcott    Altus OK