Worth doing cheap "thermal protection fuses" in hot amps? - diyAudio
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Old 13th June 2008, 05:10 PM   #1
cfcubed is offline cfcubed  United States
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Default Worth doing cheap "thermal protection fuses" in hot amps?

Searched around here & didn't see anyone saying they use them, but is there any benefit to strapping "thermal protection fuses" to your heatsinks, etc.?

Feel its a noob kind of question, but I've now got a Mini-A awaiting boxing (based on BrianGTs nice black PCBs - thanks Nelson & those involved!) & planning to tackle an F1 clone for my HornShoppes...

BTW, I've two of these nice power switch driver boards that can incorp real thermal protection... Don't want to place another mouser order & wait for the parts

I *think* I read around here that these designs are not subject to thermal runaway, so maybe these steps are unnecessary...

TIA for any thoughts.
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Old 13th June 2008, 08:19 PM   #2
Magura is offline Magura  Denmark
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At 128C on the heatsinks, I think you will rather need a fire extinguisher


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Old 13th June 2008, 08:42 PM   #3
cfcubed is offline cfcubed  United States
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Quote:
Originally posted by Magura
At 128C on the heatsinks, I think you will rather need a fire extinguisher
Magura
Good point. Perhaps on the MOSFET mounting screw/washer itself? Like w/a metal mount...
Thinking only something sensing temp on the device itself could prevent something like I saw around here where a loose MOSFET rotated & fried speakers. BUT probably not a great idea to bring A/C that close to it anyway.

Guess there's no gain here w/thermal fuse... Going w/real thermal sensing circuit (& maybe 70 deg. C or so thermistors) is the way to go if thermal protection is wanted.
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Old 15th June 2008, 12:08 AM   #4
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Consider using a thermal switch such as the Cantherm. It's normall closed and operates up to 10amps. Attach one to each heatsink, and wire it in series with the hot side of your AC supply. The devices opens above it's specified temperature, thus turning off power.

The part linked below opens at 60 degrees C.

Cantherm part #: B1206025AEDA0GE

http://search.digikey.com/scripts/Dk...me=317-1395-ND

Others here might have a better part or idea to contribute.

-David
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Old 15th June 2008, 03:27 AM   #5
cfcubed is offline cfcubed  United States
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Quote:
Originally posted by dw8083
Consider using a thermal switch such as the Cantherm. It's normall closed and operates up to 10amps. Attach one to each heatsink, and wire it in series with the hot side of your AC supply. The devices opens above it's specified temperature, thus turning off power.

The part linked below opens at 60 degrees C.

Cantherm part #: B1206025AEDA0GE

http://search.digikey.com/scripts/Dk...me=317-1395-ND

Others here might have a better part or idea to contribute.

-David
Thanks David... That is more along the lines of simple device I had in mind
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