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Ed Rodriguez

Cree 3-Way LED Bulb: Some Quick Observations

Ed Rodriguez
Ron Amok
Ron Amok
8/23/2014 4:17:56 AM
User Rank
Luminaire
Re:Curious, George-- WHAT WOULD STEVE jOBS DO?
When a company gets to a certain size, the risk averse people take over the organization and the entrepreneurs get tossed aside.Either that, or some idiot in marketing was wielding the "brand" requirement over the design.

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semiman
semiman
8/22/2014 10:24:44 PM
User Rank
Candle
Re:Curious, George-- WHAT WOULD STEVE jOBS DO?
At their volumes and complexity commonality at best makes pennies impact. There is no large tooling or engineering nre to recover.

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kdawson
kdawson
8/22/2014 11:22:54 AM
User Rank
Editor
Re:Curious, George-- WHAT WOULD STEVE jOBS DO?
In the specific case of Cree, we know that a guiding principle there is to build on a common platform whenever possible. Margery showed that the Cree A21 3-way rides on the same chassis as the 100W. They would have to develop a new and larger platform to do as you suggest. They couldn't do that any more economically than anyone else could. Their price leverage is the manufacturing efficiencies of common platforms.

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Ed Rodriguez
Ed Rodriguez
8/22/2014 10:22:29 AM
User Rank
Blogger
Re:Curious, George-- WHAT WOULD STEVE jOBS DO?
Speaking of Curious George-Can somebody give me some logical comment on the following, regarding three-way bulbs (a senior engineering mgr, back when I was a rookie out of college, was known for saying  to folks at meetings.. "there you go again, trying to introduce logic into an illogical situation"

We know--

1)  that the 3-way bulb market for 6o years has not only had 25/75/100 type bulbs but to a greater degree 50/100/150 types so that when in max setting, they were really bright, to overcome the attenuation always caused by lamp shades

2) atleast 95% of 3 way bulbs are used in table or floor lamps selling for over $25-30m with shades and 95% of those lamps have "harps" to attached the shade.

3) over 95% of such lamp/harp combinations will accommodate not only A-19 and the taller A-21 but will easily accommodate a 5.5" MOL 150 watt bulb--- but even more importantly will easily accommodate a lamp with even 6 inches MOL like some high wattage CFLs.

My info is not anecdotal but comes from detailed data from a a past client making  regular and 3-way incandescent lamp adapters for table and floor lamps.

 I have noted the fact that the Cree 3-way runs very hot (no surprise)--at temps which, in a commercial lumenaire,  or even a hardwired residential fixture, would be unacceptable.

It would be a no brainer for them to spend 50 cents to upgrade driver circuitry and  to add a few more LEDs to producea 3-way up to maybe 125 watts , genuinely matching more closely the historical 3-way market. lumen output  across he board via several models, Furthermore, with a 6" MOL they could provide far more cooling, drop the temp down 30 degrees, get better lumen output (less heat related dropoff), better reliability etc etc.

--ie be done with it.  The extra MOL, unlike as for one-way A-19's which might be screwed in anywhere and have height limits,  is non issue for the 3 way,which is virtuALLY  NEVER screwed into anything but a shaded floor or table lamp where there is no such height problem in 95% of situations.

Why keep forever nibbling around the edges on this, with agonizingly slow, marginally acceptable "improvements".  At this stage, this is not a technology or cost problem.  If Steve Jobs were running Cree bulb group, he would say "just do it !!!"

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semiman
semiman
8/22/2014 8:05:58 AM
User Rank
Candle
Re: Now you have me Curious, George
Ron just when I lose faith in you ... You speaks the truth :-). I certainly question the impartiality of her site ... Well and technical quality, detail, usefulness, her knowledge, etc.

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Ron Amok
Ron Amok
8/21/2014 9:04:39 PM
User Rank
Luminaire
Re: Now you have me Curious, George
No value I an add other than blowing one up.

Margery has already done a teardown on her Cree, er, Designingwithleds, blog site.

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Ed Rodriguez
Ed Rodriguez
8/21/2014 5:16:43 PM
User Rank
Blogger
Re: Numbers?--Lumen Measurements ?
I did not and cannot make actual lumen measurements. To do that one must have an integrating sphere, as is  used for LEDs or bulbs, or a goniometer,which is typically used for "lumenaires".  To take a lumen measurement, one must be able to record all the illuminated light from every direction as though the light source were an illuminated "sphere" with an infinite number of light rays shooting outward.

It is not possible to make a lumen measurement with a instrument's photodetector aimed at bulb.

So what I can do is take a light flux (ie footcandle) measurement, knowing it will rise or fall accurately  in proportion  to the "total" lumen change. So for a 3-way bulb I can take a "relative" lumen change with each setting. But I have no  away of knowing if the lamp's published lumens at any specific level are accurate to begin with.

What I sometimes do is take a footcandle measurement of, for example, a 100 watt incandescent,  trust the  lumens  labeling to be fairly accurate, replace it with LED bulb and compare. 

In last few years, with non Lighting-Fact bulbs, I have occasionally found that the LED bulb had a much lower foot candle reading in that condition if with similar spherical pattern, telling me the published lumen figure was bogus. THat for exampe was the case with a  new Sylvania 60 watt equivalent  LED bulb I measured 3 years ago.

So I have concluded that by using an incandescent bulb of known lumens I can use it as a reference to get a ballpark number for an LED bulb but I did not do that for the Cree bulb since I did not have a 100 watt incandescent handy (and its packaging, with lumen number ) as a reference

If anybody out there thinks he has a way to accurately measure "lumens", without a costly integrating sphere  or goniometer setup, I'm all ears.

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kdawson
kdawson
8/21/2014 2:03:38 PM
User Rank
Editor
Numbers?
Ed, did you record lumen numbers for the three levels?

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Ron Amok
Ron Amok
8/21/2014 8:30:00 AM
User Rank
Luminaire
Now you have me Curious, George


I'll see if I can pick one up at HD on Friday.

My bandsaw hasn't been fed for a couple of weeks....

 

image: wikipedia

 

 

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