In article , # Fred # wrote:
"Paul M. Eldridge" wrote in message
.. .
Actually, lamp manufacturers generally rate fluorescent lamp life
based on three hour starts (3 hours on and 20 minutes off), in
accordance with IES LM-40-1987 testing standards.
Lamp life can be extended by increasing burn cycles but perhaps not as
much as you might expect. For example, a standard GE F32T8 has a
rated life of 20,000 hours based on 3 hours per start and a 24,000
hour life expectancy at 12 hours per start.
Source:
http://www.gelighting.com/na/busines...inear_fluo.pdf
A typical CFL would have a rated service life of anywhere from 6,000
to 15,000 hours, based on the aforementioned 3 hour testing cycle. By
comparison, a standard incandescent bulb has a rated life of just
1,000 hours.
More like 2,000 hours for an A-19 lamps
Full-light-output ones by USA "standards" are rated to have typical
life expectancy of 250 hours.
and if you believe the ad for the
Lite-Saver it will last 200,000 hours.
Sounds to me like a device that is a bit common, which will extend life
of an incandescent (non-halogen one, that is) lightbulb by a factor of
optimistically somewhere around 64 (can at least sometimes actually get
difficult to dispute that item),
while reducing power consumption by about 40% (not 50% since cooler
filament has less resistance due to resistance varying with temperature),
AND...
light output is reduced about 70% and energy efficiency is roughly
halved.
A 100W lightbulb with what I consider the usual such device consumes
about 60 watts while producing about as much light as a 40W lightbulb
(whose light output is more like 30% than 40% of that of a 100W one).
http://base.google.com/base/a/418661...80019568649787 (Somewhere in the
next town in a fire station there is an incandescent at reduced voltage that
is continuously on for over 100 years.)
That is the "Centennial Bulb" - where I have an impression of lasting so
long due to design/production variation/"noise". That one has brightness
close to that of high end of a 7 watt nightlight while having a few times
that in power consumption.
Please consider that usually most of the cost of incandescent lighting
is the cost of the electricity, so energy efficiency is a factor
significant enough to force some allowance for burnouts and replacements
due to shorter life incandescents being more energy-efficient than longer
life ones.
Anyway, I have no argument for your burn life data as I've seen them as
well. But those burn figures are as good as the EPA gas mileage rating for
hybrid cars. Are those tested average burn life done under ideal controlled
lab conditions with controlled temperature, super clean power conditioned
with perfect sine waveforms, zero switching crossover, etc.? None of my
fluorescent lamps (circle-lines and compacts) have lasted anywhere near its
rated burn life even with the ones not switched as often.
You may have junky ballasts. You may be using bulbs damaged by being
driven by 2-bulb ballasts that have spent time with a bad bulb downstream
of such ballasts - that can actually dfamage "bulbs"/"tubes"/"lamps".
Also, if you have starters, bad bulbs can damage starters, and bad
starters can damage bulbs.
Lets look at one case, not scientific, just my observation, where I have a
compact fluorescent above the staircase. This fixture is only turn on about
5 seconds most of the time which is just enough for me to go up or down the
staircase and once or twice we leave it on for about a minute or two but its
switched perhaps 20 times in a day
Strong candidate for incandescents! Such duty is a case for
incandescents (preferably non-halogen) and not fluorescents!
As suggested I'll look into the "cold cathode" CFLs.
However, the only cold cathode one that sense as being on the market
easily usable for such use is a 3-watt one that is a bit on the dim side
of "15-watt incandescent equivalence" and may be dimmer than that prior to
warmup. That is a candelabra base N:Vision brand one availabe at Home
Depot, at least some Home Depots. I forget whether or not it comes with a
medium-candelabra adapter. I do know that the hot-cathode nominally
4-watt similar ones usually have such adapters.
- Don Klipstein )