Can ordinary connectors be used for thermocouples?

    Ordinary connector, here we refer to the common connector that transmits electrical signals or power. The contacts of this connector are made of copper alloy, because copper and copper alloy have excellent electrical properties. As for the thermocouple connector, we refer to a connector specially designed to transmit thermocouple signals. We have found that many people just use ordinary connectors because they don’t understand the working principle of thermocouples, or because of the simplicity of the cost-saving diagram. In fact, this is a very inappropriate approach and has greater hidden dangers.

    We know that the positive and negative electrodes of the thermocouple are made of special metal materials, and the composition ratio of each element in the material is strictly required, and it generates extremely weak electrical signals. In order to signal accuracy, thermocouple temperature measurement wires and extension wires are made of thermocouple special materials or materials with matching characteristics. Then why can't you use ordinary connectors to transmit thermocouple signals?

    According to one of the four major laws of thermocouples, the law of the middle conductor, a third conductor (intermediate conductor) is connected to the original thermocouple loop. As long as the temperature at both ends of the middle conductor is the same, the connection of the middle conductor has no effect on the temperature measurement results. If the temperature at both ends of the copper connector we use is inconsistent, then measurement errors will be introduced. This temperature difference cannot be taken for granted that it will be small. We have done experiments, using a heat gun at one end of the copper connector to increase the temperature difference between the two ends of the copper needle. As a result, the temperature measurement error of the thermocouple is as high as tens or even hundreds of degrees Celsius, while the length of the copper connector is only about 2cm. The impact of inaccurate temperature measurement data can be fatal.

    Since the principle of thermocouple temperature measurement is closely related to the material, the selection of the material is required. Generally, special wires and connectors with a specific index number are used.

    In the thermocouple vacuum connector developed by Huipu Technology, the electrode lead-in parts inside are strictly made of thermocouple special material, especially when there is a temperature difference between the vacuum chamber and the outside, it can accurately transmit the temperature signal.

(Huiputech)