Instruments: [Weekly Question] Week 33 of 2011: Questions on the thermoelectric properties of compensation wires and thermocouples
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This post was last edited by siena2008 on 2011-9-9 18:10. Are the thermoelectric properties of the compensation wire exactly the same as those of the thermocouple it is matched with? Answer: Compensation wires are cheaper than thermocouples. Within the range of 0–100 degrees, their thermoelectric properties are identical to those of the thermocouple they are used with. Therefore, using a compensation wire is like extending the thermocouple’s cold end to a control room or another location where it is convenient to take readings, and which is far away from the heat source ； However, strictly speaking, the compensation wire and the thermocouple potential are not exactly the same. For example: the compensation wire made of copper-constantan has a potential of 4.27 mV at 100 degrees, while the corresponding K-type thermocouple has a potential of 4.095 mV ； The compensation wire is copper-nickel-copper; its potential at 100 degrees is 0.643 mV, whereas that of the matching S-type thermocouple is 0.645.
This post was last edited by denghl on 2012-12-21 at 21:49. Compensation wires are cheaper than thermocouples; within the range of 0 to 100 degrees, their thermoelectric properties are identical to those of the associated thermocouple. Therefore, using a compensation wire is like extending the thermocouple’s cold end to a control room or another location where reading is convenient, away from the heat source； However, strictly speaking, the compensation wire and the thermocouple potential are not exactly the same. For example: the compensation wire made of copper-constantan has a potential of 4.27 mV at 100 degrees, while the corresponding K-type thermocouple has a potential of 4.095 mV ； The compensation wire is copper-nickel-copper; its potential at 100 degrees is 0.643 mV, whereas that of the matching S-type thermocouple is 0.645.
This post was last edited by denghl on 2012-12-21 at 21:50. Compensation wires are cheaper than thermocouples; within the range of 0 to 100 degrees, their thermoelectric properties are identical to those of the associated thermocouple. Therefore, using a compensation wire is like extending the thermocouple’s cold end to a control room or another location where reading is convenient, away from the heat source； However, strictly speaking, the compensation wire and the thermocouple potential are not exactly the same. For example: the compensation wire made of copper-constantan has a potential of 4.27 mV at 100 degrees, while the corresponding K-type thermocouple has a potential of 4.095 mV ； The compensation wire is copper-nickel-copper; its potential at 100 degrees is 0.643 mV, while that of the corresponding S-type thermocouple is 0.645
This post was last edited by denghl on 2012-12-21 21:51. It doesn’t need to be exactly the same. Since compensation wires are cheaper than thermocouples, it is sufficient that their thermoelectric properties remain the same as or similar to those of the associated thermocouple within the 0–100 degree range. Compensation wires serve to extend the thermocouple, moving its cold end to a control room where the environmental temperature is relatively stable and far away from the heat source.
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The two are not exactly the same; they generally operate within a temperature range of 100 degrees, and their thermoelectric properties are relatively similar
This post was last edited by denghl on 2012-12-21 21:52 – not exactly the same
This post was last edited by denghl on 2012-12-21 at 21:54. Reply 1#: Baghdad – The thermoelectric properties of the compensation wire should be the same as or similar to those of the thermocouple it is used with; compensation wires are employed due to factors such as lower cost. But strictly speaking, they’re not exactly the same. For example, the potential of an S-type thermocouple at 100 degrees is 0.645 mV, while the potential of its matching compensation wire, copper-copper-nickel, at 100 degrees is 0.643 mV.
This post was last edited by denghl on 2012-12-21 at 21:54. It’s not exactly the same, but it’s similar; the degree of similarity is likely over 90%
It’s different; it’s basically the same within 100 degrees