Regarding the issue of inserting a section of copper wire in the middle of the compensation wire for hot junctions
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If a regular copper wire is connected in between the thermocouple compensation wires, will the measurement error be larger or smaller? What will be the deviation if a compensation wire with the same division value is connected in between? What should be done in practical applications if the compensation wire is too short? Or if the compensation wire is broken, is there nothing that can be done?
If it’s broken, it can be repaired; using copper wire to make connections will definitely result in incorrect measurements.
If a regular copper wire is connected in between the thermocouple compensation wires, will the measurement error be larger or smaller? It depends on the temperatures at both ends of the copper wire. If the temperatures at both ends are the same, it has no effect on the measurement. When an intermediate conductor (a third conductor) is inserted into the thermocouple circuit, as long as the temperatures at both ends of this intermediate conductor are the same, its inclusion does not affect the total potential of the thermocouple circuit. This is known as the intermediate conductor law for thermocouples.
What will be the deviation if a compensation wire with the same division value is connected in between? It has no impact on the measurements. What should be done in practical applications when the compensation wire is too short? Or if the compensation wire is broken, is there nothing that can be done? Compensation wires with the same division value can be used for connection; if the ambient temperature remains constant, copper wires can also be used. It is essential to handle the joints properly during connection, with welding being the best option.
For example, a junction box is used for the compensation wire; the terminal connections are made of copper, and the temperature inside the box remains relatively constant, so that’s how it’s used. I’ve seen terminals made of compensation wire material, with graduation marks. @jiaguoyun
What a waste of time! Thank you to the original poster and the thread moderator!
If the compensation wire is broken, you can connect another one. . . . This way, there will be no errors
It mainly depends on what type of gauge is being used; if low error levels are required for measurements, it’s best to use extended compensation wires, while T-type wires can be made of copper