The thermo switch O operates independently from any power supply. The temperature is detected through a bimetal disk specified in accordance with the required switch-on temperature TE. When this fixed switch-on temperature TE is reached, this bimetal disk will snap over, closing a contact system thus closing the electric circuit of the device to be started. After cooling down and reaching the cut-off temperature TA, the bimetal disk will automatically return to its original position and open the contact.
The electric circuit is opened again.