Commonly used in low temperature zone thermocouple is a kind of temperature detector, has the characteristics of high measuring accuracy, stable performance, widely used in industrial temperature measurement. Due to the difference of the material, thermocouple has many types, such as end thermocouple, thermocouple, ordinary type thermocouple, flameproof thermocouple. End the working principle of thermocouple by special processing wire end thermocouple element ( Copper or platinum wire) Winding, fastening them in the thermometer front-end, compared with general axial thermocouple, end thermocouple can more correctly and quickly reflect the actual temperature condition of the end face being measured, the method of making it a lot, varieties of forms, suitable for power plant steam turbine and motor bearing shell or other body surface temperature measurement. Some end thermocouple installation because it fuses with the resistance element is connected, so will lead to end surface thermocouple synchronous rotation, such ability make sure end thermocouple in the installation is not artificial damage, but the actual installation process to avoid appear this kind of circumstance. Due to the emergence of this situation, face thermocouple outside the installation time only need to twist the screw is ok, don't need to lead and end surface thermocouple synchronous rotation. Know how end thermocouple works, we are end surface thermocouple installation would be easier, but need to pay attention to the thermocouple and the index number of the display instrument must agree; And in order to eliminate the influence of the connection wire resistance change, must use three wire connection.