Thermal Protection

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

  1. craigfoo

    Thread Starter New Member

    May 16, 2013
    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


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

    AAC Fanatic!

    Feb 5, 2010
  4. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    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.