Thermal cutoff (Caution to be observed when designing for use of thermal cutoffs)

Principle of Thermal Cutoff: About Thermal Cutoff; Types and Characteristics of Thermal Cutoff; Performance of Thermal Cutoff; Utilization Technology; Technology Trends

Application Instruction: Thermal cutoff (Caution); Thermal cutoff (Caution to be observed when designing for use of thermal cutoffs); Thermal cutoff (Caution to be observed when installing thermal cutoffs); Thermal cutoff (Other caution); Thermal cutoff/resistor assemblies (Caution); Thermal cutoff/resistor assemblies (Caution to be observed when designing for use of thermal cutoffs); Thermal cutoff/resistor assemblies (Caution to be observed when installing thermal cutoffs); Thermal cutoff/resistor assemblies (Other caution); Thermoprotector with resistor (Caution to be observed when designing for use of thermal cutoffs); Thermoprotector with resistor (Caution to be observed when installing thermal cutoffs); Thermoprotector with resistor (Other caution); Thermoprotector （Cautions to be observed when designing for use of thermoprotector）; Thermoprotector (Cautions to be observed when installing thermoprotector); Thermoprotector (Other caution)

When designing, make it sure to secure as much longer lead wires as possible, and put lead wires and body to the nearest place where heat generates in order to ensure the thermosensitive functions. When using thermal cutoffs in equipment with winding functions　such as transformers and motors, install the thermal cutoffs in places with good heat conductance, which will allow them to most directly sense the heat of the windings. Design equipment so that the bodies and both lead wires of thermal cutoffs are evenly heated.
Appropriate insulation distances (clearances and creepage distances in accordance with IEC 60664-1) need to be kept between lead wires of the thermal cutoffs and other conductive materials.
When designing end products, be sure that thermal cutoffs are not installed in locations where they would be subject to severe or continuous vibration.
Design end products so that, after a thermal cutoff functions due to abnormal heating of the equipment, the thermal cutoff does not reach a temperature above its maximum temperature limit owing to overshoots.
Install thermal cutoffs so that their function is triggered only by abnormally high temperatures.
Although thermal cutoffs are highly reliable, there are limits to the abnormal states with which a single thermal cutoff can cope. Further, if a thermal cutoff is damaged for some reason, it is possible that it will not break a circuit under abnormal conditions. If there is a possibility that personal or property damage would arise if a circuit is not broken during abnormal equipment operation (i.e. when there is a high required safety level), it is effective to add one or more thermal cutoffs with different temperature ratings.
The mechanical strength and rigidity of the hardware used for mounting the thermal cutoff shall be adequate. Brackets, clamps or screws used for mounting the thermal cutoff shall withstand thrust and tensile forces, torques, vibrations and cyclic temperature changes expected during normal operating conditions of the equipment.
The mounted thermal cutoff shall be adequately protected from harmful effects produced by possible spillage of liquids from the equipment, for example by covers.
For sealing-in with impregnating fluids or use of cleaning solvents, investigation (trial tests) with prototypes and initial products is required to ensure that intended sealing or cleaning does not affect marking and function of the thermal cutoffs for each individual application.