Long Live the Incandescent! - Page 2

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Re: Long Live the Incandescent!
Have you managed to get through Rod Elliott's article? It's quite well done
with excellent use of supporting data.


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Re: Long Live the Incandescent!
Yes, I finished the article.  It was a serious piece of work.  I was
disappointed that it was so heavily into the CFL with very little on
LED.  He did bring up some points about CFLs which I had not thought
about before.  All in all a good read.  I still like LEDs ;-)



On Jul 10, 7:25=A0am, nob...@whocares.com (Dave Houston) wrote:
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Re: Long Live the Incandescent!

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The notion that there is/will be a single 'winner' has always been -- and
will continue to be -- overly simplistic in my opinion.

As new technologies emerge, they in turn provide opportunities, increase
expectations, and create niche markets for what ultimately become 'must-have'
goods. For example, many of us can remember when dimmable electric lights
were not one of life's necessities ;-)

The lights in our kitchen are an example. There are now halogen incandescent,
CFLs and LEDs in the ceiling cans. The LEDs are purposely 'white' types that
complement well the natural daylight through the window. The CFL cans are
3200K and match the halogens at full brightness. 12vdc track lighting
provides task illumination and, when dimmed, warm lighting for ambience.

The mix is similar but different on the outside of the house. I still haven't
had to tie two ladders together to replace the halogen floodlights up at the
third floor eves. And maybe I won't have to because we changed our outside
lighting strategy to use  candelabra-base CFLs' in the existing yard-level
lamps and only turn on the floods as an emergency/security/special need. In
this way we save maintenance, electricity and, with our change in expectation
and behaviour, even better than before.

I also recently purchased an outdoor RGB LED wall-washer that is controlled
by DMX512. It's the cat's meow for outdoor lighting. The output of the
110VAC-> 24vdc power supply is externally accessible. so it will be simple to
power from the distributed DC power system in our house with its intrinsic
backup.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=250448983502

It can be 'infinitely' dimmed, the color changed subtly or garishly, and made
to strobe or flash or otherwise vary intensity or color systematically for
holiday lighting, or panic/emergency signaling or ambience, or whatever.

I've been experimenting with DMX in my house for a decade. The emergence of
RGB and RGBY lighting becomes a compelling reason to have the multi-channel
capability that DMX-512 provides. Eventually being able to change color
and/or color temperature may become as much a "must-have" as dimmers ;-)

... Marc
Marc_F_Hult
www.ECOntrol.org

Re: Long Live the Incandescent!
On Thu, 9 Jul 2009 07:33:28 -0500, "B Fuhrmann"


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To (hopefully) clarify, LEDs are in fact intrinsically "dimmable". Their
light output is conventionally dimmed by holding voltage more-or-less
constant and reducing current.  

But incandescent lamps are typically dimmed by reducing average voltage, not
current. So in practice, standard, conventional TRIAC-based dimmers are not
well suited for dimming LEDs because they dim by reducing average voltage and
current is held more-or-less constant (varies with filament temperature)
during conduction.

Another issue is the 'dimmer curve' of particular wall-mounted dimmer. One
description of a dimmer curve is the relationship between the rotation (in
degrees) of a physical dimmer knob to the phase angle (in degrees)of the
TRIAC conduction (output).
 
A typical household dimmer curve that is appropriate for incandescent lamps
may not be appropriate for an LED-based lamp. This issue is well addressed by
emerging electronic solutions as well as by some existing conventional
'professional'  dimmer consoles and panels such as those used in
entertainment venues using DMX (DMX512)

There is at least one IC  on the market that addresses both the
current-control and dimmer-curve issues by interpreting the complex "chopped"
waveform created by a TRIAC-based dimmer into the information needed by an
LED for continuous dimming with a useful dimmer curve and then providing the
appropriate current to the LEDs.

National's LM3445 detects the 0-180 degree phase angle of a conventional
TRIAC dimmer output and translates that information into a current output
with a 1:100 dimming range (about 6-1/2 f-stops of light).

http://www.national.com/analog/led/triac_dimming

Incorporation of this sort of smarter electronics into LED lamps will reduce
or eliminate the problem that Bill describes. I have a pair of dimmable LEDs
intended for ceiling cans in the kitchen which I can place on the same
circuit as halogen incandescents and CFLs in which they perform admirably.
Like CFLs, and unlike incandescents, they are not 'infinitely' dimmable, i.e,
they have an abrupt shut-off at about four to five f-stops below full
brightness.

HTH ... Marc
Marc_F_Hult
www.ECOntrol.org

Re: Long Live the Incandescent!
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Vendor, manufacturer, model numbers?

Thanks!

Steve

--
steve <at> w0x0f <dot> com
"Life should not be a journey to the grave with the intention of
arriving safely in an attractive and well preserved body, but rather to
skid in sideways, chocolate in one hand, chip shot in the other, body thoroughly
used up, totally worn out and screaming "WOO HOO what a ride!"

Re: Long Live the Incandescent!

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Mine are Cree LED Recessed Lighting Luminaire LR6C 6" Downlight Module and
are "Neutral Color 3500K" which provides daylight, i.e., cooler than
incandescent light..  As I recall, Cree also sells a warmer, 3200K version.

GooBing  " Cree LR6C " for FAQ, vendors and manufacturer site.

They are expensive -- ~ U$87

Among the claims on the LR6C box are:

    1) "Designed to last 50,000 hours"
    2) ' uses 85% less energy than conventional bulbs and 50% less
        than CFLs"

Note that CFLs and LEDs do not intrinsically put out warmer light when dimmed
as do incandescent lamps. I suspect that some bright manufacturer will
realize that part of the attraction of dimming incandescents is the resulting
reduction in color temperature. One can, of course create most any color with
a RGB or RGBY LED lamp using multi-channel DMX-512 (DMX512a) control.

I note that one web site cites specs of "dimming to 25%".  I'll remeasure.

HTH ... Marc
Marc_F_Hult
www.ECOntrol.org

Re: Long Live the Incandescent!

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Thanks for the reference. I'm looking a the can compatibility, and it
looks like they want most 6" cans, and the trims snap onto the lights,
not the cans. Also need to see if they're compatible with UPB dimmers.

Steve

--
steve <at> w0x0f <dot> com
"Life should not be a journey to the grave with the intention of
arriving safely in an attractive and well preserved body, but rather to
skid in sideways, chocolate in one hand, chip shot in the other, body thoroughly
used up, totally worn out and screaming "WOO HOO what a ride!"

Re: Long Live the Incandescent!


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Yes, The LR6/LR6C trim replaces the existing trim in a retrofit. My existing
ceiling cans were not among those listed by Cree as compatible, and as I
recall, it took a minor tweak to coax them to fit. Something I'd want to
avoid if building a house from scratch but near-trivial compared to many
other retrofit tasks.

My only complaint is the high price. I do also note that the LR6C "Neutral
Color 3500K" seems much cooler than the 3400K photofloods of yesteryear. This
is consistent with Cree's indicating that their LR6 "warm" lamp is 2700K, not
3200K as I mis-remembered/wrote in my previous post.

Cree readily agreed to exchange my LR6C's for LR6's at no cost, but once I
got used to actually seeing and using mixed-temperature lighting, I 'warmed'
to the notion and decided to keep them. They are directly in front of a
north-facing window and complement and extend and simulate daylight from the
window very well.

HTH ... Marc
Marc_F_Hult
www.ECOntrol.org

Re: Long Live the Incandescent!
I can see a relatively quick payback for these Cree LR6C lamps in a
commercial/industrial application, but for a home where they may not
be used more than an hour or two per day the payback would be many
years, unless they get the price down.

On my visit to the Cree website I didn't see any mention of dimming
capabilities.

And lastly, I hope they do a better job of living up to the claimed
life expectancy than CFL's did.

One place I would really like to incorporate LED lamps is under our
kitchen cabinets.  I presently use inc. rope lights above the cabinets
and halogen under the cabinets.  These new LED strips are interesting,
but they all have bulky power supplies to deal with.  Have you used
any undercabinet LED's Marc?

Re: Long Live the Incandescent!

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Our kitchen lights are not only the longest of any main interior light, they
had the highest power use before I switched to a mixture of incandescents and
LEDs ( 9 x 120watts = 1080 watts)

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Note that the company has both www.cree.com and www.creelighting.com sites
with limited linking between the two. Residential products are primarily at
creelighting.com not cree.com

Dimming is variously listed at 20% and 25% ; Also power factor > 0.9
http://www.creelighting.com/downloads/LR6.pdf
http://www.creelighting.com/downloads/LR5.pdf
http://www.creelighting.com/downloads/LR4.pdf

I use DMX/analog-controlled dimmers with large inductors (chokes) mounted in
a panel in the basement for the kitchen lights, but Cree lists compatible
conventional dimmers:
http://www.creelighting.com/downloads/Dimmer_Compatibility_Rev011608.pdf

Lutron also has tested and recommends many of their dimmers with Cree lamps:
http://www.creelighting.com/downloads.htm

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Time will tell but the signs are propitious. The vulnerability of LEDs is
similar to that of CFLs in that it appears that a common failure mode of CFLs
is for the electronic circuitry to be cooked and then die and LEDs also
require at least some electronic components when used directly with AC
sources.  Many of the failures of CFLs have been in base-up or enclosed
environments. (Remember the X-10 "socket rocket" and its short life when used
in base-up orientation ?) But Cree has designed their units for specific
orientation, geometry, and environment, namely 4", 5" and 6" ceiling cans and
so has theoretical  and empirical knowledge of the heat production and
temperature distribution in normal, code-compliant use.


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Funny you should ask.  ABIR, in decades of putting up with my HA experiments,
my better half has never actually made a specific request until recently --
namely to illuminate the dark space under the black steel shelf I installed
for the black microwave and touch screen where the black coffee-making
gadgets are stored next to the black soapstone back splash. (OK. So I created
this black hole and now have to deal with it ;-) No progress or decisions
yet. I am (unduly?) fascinated by the potential for RGB and RGBY LEDs.

... Marc
Marc_F_Hult
www.ECOntrol.org

Re: Long Live the Incandescent!
Dave Houston wrote:
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Don't bother. LED lighting is the future.

--
Dirk

http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.onetribe.me.uk/wordpress/?cat=5 - Our podcasts on weird stuff

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