To what temperature can a radiator safely heat up?

Question

Cooling systems

Good afternoon!
I assembled a lamp on powerful 6-watt LEDs, they are fixed with hot-melt adhesive on a radiator with longitudinal ribs. During operation, according to the datasheet, they heat up to 100 degrees. The radiator also heats up seriously over time. I want to understand if it will heat up so endlessly until it heats up to the temperature of the diodes at all and can not cool them? How to check?

Answer 1

https://electronics.stackexchange.com/questions/30...
There are a bunch of other links.
In short, the way you are trying to figure it out is not considered. And 100 degrees for LEDs is fucked up. So that they do not degrade faster than incandescent lamps, they must not be hotter than 70 degrees.
I'll add some details.
- "According to the datasheet, they heat up to 100 degrees" - incorrect. This is the maximum allowable, not the nominal operating temperature.
- It is impossible to judge the efficiency of a radiator only by its temperature, because the thermal resistance of the junction between the LEDs and the radiator is an unknown value. With high resistance, the LED may, conditionally, already burn out, and the radiator will still be barely warm. You can judge the cooling efficiency by temperature only if you measure the temperature of the LED. This temperature is the only baseline that matters.
- Since the scenario of using the lamp is not described in the question, it is not clear how to consider the situation at all. Because, for example, for a short-term switching on mode, it is a radiator (a device that performs intensive heat exchange with the medium through convection and radiation) is not needed. I made several illuminators for macro photography and microscopy for such a mode, where a piece of metal with a high heat capacity, but low heat dissipation (it was corny cheaper and faster) served as a heat sink. But for a situation of constant operation, such a trick would not work, because the heat sink would heat up quickly enough and cease to provide a low temperature for the LED case, since heat dissipation from its surface would be clearly insufficient.

Answer 2

The heatsink will try to warm up to the temperature of the LEDs. Endlessly. But since it will dissipate at least some heat, with sufficient fins and dimensions, the temperature will be slightly lower than the current one for the diodes.
To check, use two thermal sensors, one on the side wall of the LED, the second in the base of the radiator.
Then turn on the LEDs at 90% of the planned power. Well, then look at the temperature difference. As soon as it exceeds 80 on the diode, it is desirable that the radiator be 70 or less.
PS Usually the heat dissipation is indicated in the specs. You can calculate the required radiator in special calculators

Answer 3

Is there a simple solution to make the power open when a certain temperature is reached?
Apparently, this is done using a thermostat. But I don't know which one to choose. I have 2 6 watt diodes