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I need to source a very small thermal switch that would fit beside a peltier and open at approx 50 C. Answered

This is to prevent someone from getting a burn. I was thinking of the small battery cut offs but I do not know if they reset once opened.  The smaller the better as it would be ideal if it was flush with the peltier. I would like to wire it to the power source as a simple mechanical thermostat. 
Power supply ranges from 5V, 500ma to 13V, 1A.
It needs to be simple as there is no logic board.

Thanks,

Paul

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messyworkbench

7 years ago

This is for my son's science fair project. He is making a USB beverage cooler/heater. Current designs heat/cool air inside an insulated container but at a maximum 2.5 watts from a USB they are pretty ineffective.
He will have the pop can/cup sit directly on the peltier, which is on top of a heat sink, which is on top of a fan, which sits on a fan guard. Even at 2.5 watts this can actually cool down a warm pop and heat up a cup of coffee. An on-off-on rocker switch is used to reverse the polarity to the peltier to make it heat or cool down beverages. I would like to see him have some sort of safety feature. The link to Selco is much appreciated, I prefer to support those that support this site. The UP72 looks like what he needs but I do not know if this would reset by itself for numerous cycles or is it a "one shot" as with a thermal fuse, or limited switch cycle life? I assume you order them with the temperature range you want and they are preset for you?
Usually a switch such as steveastrouk suggested is used but they are too bulky.
Thank you very much for all of your help, I appreciaete your answers and I believe I am getting close to what is needed.
Paul

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steveastroukmessyworkbench

Answer 7 years ago

The second item I suggested isVERY small, and we use them in our own Peltier systems.

Steve

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messyworkbenchsteveastrouk

Answer 7 years ago

Man, I should slow down sometimes. Yes, that looks very promising. Funny that they are/were made in Canada.
Could I attach the tab to the peltier with epoxy and have the heat transfered to the device by the tab or is the tab used for fastening?
I would prefer not to have to put on a section of copper to distribute the heat as we have to keep the device light. When in use it will be attached to pop can/coffee cup.

Thank you again, this is wonderful help.

Paul

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lemonie

7 years ago

Heated-seats?

L

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kelseymh

7 years ago

Thermal cutoffs (also called thermal fuses) are single use devices. They're wired in for personnel and equipment safety. It sounds like you're looking for something like a resettable circuit breaker which can be triggered on temperature.

Ah, ha! Do a Google search for "thermal circuit breaker". One of the sponsored links (blech) is Selco Products. Check out their "thermal protectors" line, which I think is what you want.

Once you've got a useful set of keywords and/or part numbers, you can try searching Google, or other electronics suppliers directly, to get a good price.