First, we start with a heatsink which we can spin, vaguely similar to this one [link].

Then, we give it a very thin coat of thermally conductive white paint.

Next, instead of putting the heatsink on top of something needing cooling (such as an IC), we put our components which need cooling (our LEDs) on top of the heat sink.

The spinning of the heatsink creates air flow, which keeps it (and the LEDs attached to it) cool.

By operating at a lower temperature, the rate of decrease of the luminous efficiency of the LEDs is reduced... or in other words, they last longer.

Perhaps equally important, if the heatsink is spinning fast enough, each LED will appear to be a circle of light, instead of a dot of light. This makes the light appear more diffuse.

If each LED is mounted at a different radius, the spinning, lit up, heatsink will appear to have several concentric rings of light on it. This makes the light even more diffuse.

There will be a certain amount of noise, but if the motor is quiet, and the heatsink fins are the right size and shape, and the LEDs don't produce excessive turbulence, then the noise level will be relatively low.
-- goldbb, Mar 29 2013

Sandia's spinning heatsink https://share.sandi...ws_releases/cooler/
Who'd've thunk that air bearings would have such a high rate of heat transfer? [goldbb, Mar 29 2013]

Sulfur Lamp http://en.wikipedia.org/wiki/Sulfur_lamp
Uses rotation to assist heat distribution. [spidermother, Mar 31 2013]

Some of you might be wondering, why LEDs need cooling, when they supposedly "don't produce heat."

The answer is simple: Although LEDs produce much much less heat than the incandescent lamps they replace, they are not completely heat-free.

For example, GE's upcoming LED-based replacement for a 100W incandescent lamp uses 27W, and it will make at least as much heat as a 23W incandescent lamp.

Since LEDs are extremely sensitive to heat, not having enough cooling could drastically reduce the lamp's operating life... which would be very "not cool" when the lamp could cost as much as $100.
-- goldbb, Mar 29 2013


Seems like the weak link would be the commutator- how many hours can those last?

You would tap into the motor commutator, I imagine.
-- Kansan101, Mar 30 2013


Just make it an induction motor: no commutator and it runs natively off of AC. Typically the conductors in a squirrel cage rotor are high current low voltage already which is good for powering the LEDs. I suppose the design would be quite different that an induction motor in existance since that would need to be an extremely small motor (probably much less power than a pager vibrator motor), yet the coils would have to transfer extra power to the rotor to power the LEDs.
-- scad mientist, Mar 31 2013


// Seems like the weak link would be the commutator- how many hours can those last?  //

The bearing is a weak link. How often do cooling fans fail, or hard-disks don't start up?
-- Ling, Mar 31 2013


In [scad]'s configuration, the induction motor would also act as ballast for the LEDs.
-- spidermother, Mar 31 2013



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