Thermal Protection

Discussion in 'Electronics Resources' started by craigfoo, Jul 1, 2013.

  1. craigfoo

    Thread Starter New Member

    May 16, 2013
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    I have a heating element that I crank up to 230 C but I don't want to exceed 250 C. I have a thermistor to give me temperature feedback but I want a backup in case the thermistor fails. It needs to be small (0.25" W x 0.5"), resettable, and have the ability to wired in series with my heater element so it can break the circuit if it exceeds 250 C. A Bi-metallic switch would be perfect but I can't seem to find a small one. A thermal fuse would work if I didn't have to remove it when it tripped. Anyone have a part in mind? I've been searching around the webs and the googles for awhile.
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,028
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    What is the heater current?
     
  3. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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  4. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
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    I think you are pushing it a bit close with the 230 / 250 'C values.

    A typical resettable thermal fuse might have a 15'C range where it trips off, and maybe 20 to 25'C hysteresis.

    Normally the resettable thermal fuse needs to be at least 40-50'C above the regulated operating temperature. You might be able to cut it a bit closer, but risk getting issues.
     
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