On Tuesday, 13 March 2018 12:40:55 UTC, The Natural Philosopher wrote:
On 13/03/18 10:27, Scott wrote:

Very helpful. Mind is in a globe (bathroom light) but it is quite a
big globe. I won't go overboard with output..

Short engineering dissertaion on heat dissipation.

What kills incandescent lamps is "hours on".

What kills lampshades is peak temperature. That why they have lamp
wattage ratings. 90% of an inmcandescent is heat so to a first
approximation a '60W lampshade' can take 60W of heat in its middle
without going brown or catching fire..

What kills LEDs is the product of life and of temperature. The hotter
they run the shorter they run.

However most LED *CHIPS* will stand to run at 100C or more.

What this means is that *NO* LED is going to scorch that lampshade. To
get 60W of heat you probably need 80W of LED, and that probably will
not fit in the lampshade. And would blind you!

I've just grabbed a candle LED that is about 40W equivalent, and its
about 40C. That is par for the envelope of a LED bulb.


Ergo the only critical factor is whether the lampshade will overheat the
LED.

so far so good

Frankly if it's designed for an incandescent the answer is hell no!.

I've even put LEDS in enclosed cooker hoods and fully enclosed
luminaires and they have been FINE. For several YEARS.

yes, with limited use. You've got 15k or 25k hour life lamps, a year on 24/7 is only 8760rs. If you're willing to live with much reduced life, great, go for it.


As usual tabbypurr is pontificating from limited armchair theory and
zero real understanding.

whoosh.


NT