On 09/11/2015 18:36, John Robertson wrote:
On 11/09/2015 8:40 AM, Ivan Vegvary wrote:
Replacing thermal fuse in wall oven power supply.
Does fuse measure temperature of ambient, or, temperature based on
current through fuse?
I ask because I would like to attach wire leads to fuse since I
screwed up soldering directly to the board.
Thank you.


Thermal fuses are supposed to open when their temperature rises above
their design failure point.

Certainly if you pass too much current through it will fail! Most
thermal fuses are on heat sinks or fans and open at relatively low
temperatures to indicate that the fan or cooling system has failed and
this helps to protect the electronics from heat failure.

Due to their sensitivity they are hard to solder without opening
internally! You MUST heatsink the leads to protect the element inside
the thermal fuse from getting too hot. A heatsink can be the jaws of
needle nosed pliers or similar clamp with lots of metal to absorb the
heat of soldering. I'm not certain that all types of thermal fuses can
even be soldered - most I've seen have metal clips clamping them to the
wires. You may have to experiment. You probably should get more than one
in case of failure...

Pigtail screw-on clips might work fine.

John :-#)#


Another tip is to freezer spray the body of the thermal fuse before
pre-tinning the wires and then repeat freezing before soldering proper.