Guest
On Tuesday, 28 May 2019 20:23:16 UTC+1, pf...@aol.com wrote:
that [partially] applies to the higher power lamps only. 3w reflector lamps are good in any position, and are of course mostly used facing downward. Partially means lamp life is affected, but it still works.
> b) The driver (what is in the base) emits heat. Approximately 80% of all the heat generated by the lamp. The other 20% is spread throughout the emitters and in terms of 'feel' will be negligible.
No. The LEDs are the load, the driver is somewhere vaguely in the 90% region of efficiency, therefore the LEDs emit around 10x as much heat as the driver. Some lamps couple the LED heat to the base as a way to get some more heat out, a lot don't. Your belief would require 25% efficient SMPSUs! Even a crude 1 transistor smpsu using a screw for an inductor core can beat that..
> c) Keep in mind that an LED lamp, on average, makes about 150 - 200 lumens per watt. Let's use 200 for this discussion.
15w for 1500 lumens is currently typical for domestic lamps, or 100lpw.
What in your opinion is the problem with a 100w equivalent 15w LED in an open ventilated 20w rated lampholder?
NT
Some basics:
a) ALL LED lamps should be used base-down unless otherwise marked. Yes, there are LED lamps designed for horizontal, vertical, base-up and base-down applications. But if UNMARKED, base-down only.
that [partially] applies to the higher power lamps only. 3w reflector lamps are good in any position, and are of course mostly used facing downward. Partially means lamp life is affected, but it still works.
> b) The driver (what is in the base) emits heat. Approximately 80% of all the heat generated by the lamp. The other 20% is spread throughout the emitters and in terms of 'feel' will be negligible.
No. The LEDs are the load, the driver is somewhere vaguely in the 90% region of efficiency, therefore the LEDs emit around 10x as much heat as the driver. Some lamps couple the LED heat to the base as a way to get some more heat out, a lot don't. Your belief would require 25% efficient SMPSUs! Even a crude 1 transistor smpsu using a screw for an inductor core can beat that..
> c) Keep in mind that an LED lamp, on average, makes about 150 - 200 lumens per watt. Let's use 200 for this discussion.
15w for 1500 lumens is currently typical for domestic lamps, or 100lpw.
d) This lamp will make very roughly 6,400 lumens, and about 26 watts in heat at the base. Note that the 10,000 lumens advertised is what is known in the industry as "Flash" lumens - the first 3 seconds that power is applied to the LEDs for the first time - and then only.
e) A typical incandescent lamp produces about 17 lumens per watt these days. But heat is emitted across the entire envelope, not concentrated in the base as with CFL or LED lamps.
f) Hence, ladies and gentlemen, boys and girls, and children of all ages - BASE DOWN unless marked otherwise. AND!!! the lamp base rating should be observed as compared to actual light delivered.
g) Meaning - if a base is rated for "60 watts", an ~1.100-lumen lamp should be pretty much the limit of what is installed in it, whether incandescent, CFL or LED.
Peter Wieck
Melrose Park, PA
What in your opinion is the problem with a 100w equivalent 15w LED in an open ventilated 20w rated lampholder?
NT