Thermal Fuse Effectiveness

[TurboXS]

I posted this in the Mechanical Engineering section but perhaps it should have been in here as I haven't seen much response to it.

thread391-156025

regards
Pete

 

[zappedagain]

That sounds easy enough to prototype... especially if you don't mind potting a thermocouple in the Sylgard so you can measure the temperature.

Some rusty thoughts...

The question doesn't really seem like how hot will it get, but how long will it take to trip? What is the spec on your fuse (1 hour at 150C, 1 minute at 160C, 1 second at 170C, etc.). You'll have to determine a useful response time first.

From the EE perspective a more meaningful question seems like 'how much power will the resistor dissipate before it trips the fuse?'. Then you can work with thermal conductance (watt/C).

A quick look on the web shows a thermal conductivity of 0.85 watt per (meter degree Kelvin).

http://www.dowcorning.com/applicati...sp?l1=009&pg=00001122&prod=M0001578&type=MRKT

(caution - I also see lots in the Sylgard family so make sure you get the right material)

http://en.wikipedia.org/wiki/Thermal_conductivity

At this point I'd have to hit the heat transfer books too to figure out how to convert the thermal conductivity into a thermal conductance for your package.

I hope that gets you started.

 

[zappedagain]

If you don't get any additional activity on this post you might try forum391 Heat Transfer & Thermodynamics engineering