ST07 Series Thermal Protector Working Principle：

When the circuit works normally, the contact is in a closed state. When the rated operating temperature is reached, the bimetal discis deformed by heat and snap rapidly, cut off the circuit. After that, the device begins to cool down. When it reaches the defined reset temperature, the bimetal disc and the spring disc snaps back intoits start position, the contacts will close again, and the device startsworking again.