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Re: [RFI] Cree LED Light Bulb

To: "EDWARDS, EDDIE J" <eedwards@oppd.com>
Subject: Re: [RFI] Cree LED Light Bulb
From: "Dale J." <dj2001x@comcast.net>
Date: Mon, 11 Aug 2014 15:41:02 -0500
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
The glass part of the CFL gets very hot, too hot to touch and that's where the 
heat is.

Dale, k9vuj

On 11, Aug 2014, at 14:25, "EDWARDS, EDDIE J" <eedwards@oppd.com> wrote:

> I have to admit my experience with CFL bulbs has been very limited until the 
> last few years.  So I might be and probably am missing something in this 
> discussion.
> No one seems to be accounting for the heat generated by the ballast base of a 
> CFL bulb where there is usually a small circuit housed inside.  This may even 
> vary for each manufacturer.
> 2 things I haven't pinned down yet:
> What is the normal amount of heat generated by the ballast of CFLs?
> Is ballast heat included on the CFL wattage rating?
> I have heard some CFLs have warnings they should not be used inside enclosed 
> fixtures (open fixtures only), and others warn against using them mounted 
> upside down.  I assume this is due to ballast heat.  But I could be wrong.
> 73, de ed -K0iL
> -----Original Message-----
> From: RFI [mailto:rfi-bounces@contesting.com] On Behalf Of Charlie Gallo
> Sent: Monday, August 11, 2014 1:05 PM
> To: Peter Laws
> Cc: rfi@contesting.com
> Subject: Re: [RFI] Cree LED Light Bulb
> On 8/11/2014 Peter Laws wrote:
>> On Mon, Aug 11, 2014 at 10:25 AM, Kim Elmore <cw_de_n5op@sbcglobal.net> 
>> wrote:
>>> That's interesting as in their on-line FAQ, Cree says they approve of 
>>> installation in can fixtures. We've had 42 W CFLs in there for the last 8 
>>> years and never seen evidence of overheating. However, the light is cycled 
>>> a lot and I suspect the failures we've seen are related to that. Cree again 
>>> states that power cycling is harmless to their LED bulb. I guess I'll get 
>>> to find out!
>> Lumens, gentlemen, please!  IMHO, bulbs should also receive a rating
>> based on how much heat they generate.  Clearly, there is a difference
>> in the heat output of an Edison bulb that consumes 60 W of power and a
>> CFL that puts out the equivalent light (at considerably less power
>> consumption).
> Actually, we know this:
> The TYPICAL 60 Watt soft white edison bulb generates 800 lumens.  Now,
> if  there  was  100% luminous efficiency, you get 683 lm/W, so you are
> getting 1.17 watts of actual light, and 58.83 watts of heat
> The cree bulb I have sitting here, which claims 75 watt equivalent and
> 800 lumens..(Interesting, eh) draws 14 watts
> Again,  you're  looking  at  1.17  watts of light, and therefore 12.83
> watts as heat
> Pretty  much,  if  you  think  about  any lightbulb, assuming it isn't
> giving  off  massive RF, or sound, anything not out the front as light
> is going to be heat
> -- 
> 73 de KG2V - Charles Gallo
> Quality Custom Machine-shop work for the radio amateur (sm)
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