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Rusty thermocouple connector 1

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circuit1952

Electrical
Aug 1, 2003
28
Will rust on a type J (Iron-Constantan) thermocouple affect the temperature measurement?
 
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It will if it is at the junction. If just somewhere along the wire, no. If it is at the connector it can also cause problems.

Keith Cress
Flamin Systems, Inc.-
 
itsmoked is correct. Thermocouples deal in millivolt potentials. Any resistance at the junction or interconnection is bad. It was common with the ceramic bead style thermocouples for the iron wire to rust if the tip of the temperature element was above 100 degree C and the head at ambient. This is less common with sheathed elements.
 
I concur with itsmoked and JLSeagull;
If the rust is on the surface it won't matter (within reason).
If the thermo-couple current must pass through the rust, in theory you have complementary junctions that should cancel.
In practice the added resistance is probably going to cause inaccuracy or complete failure.
yours
 
You need to have all the wire connections clean, any rust at the connections affect the temperature measurement
 
If it is a contact thermocouple rust could directly effect the measurement if it is a t the point of contact. I've seen this before on mild steel linework with surface mount thermocouples.

Obviously all the above are correct also. Generally rust on any connection is never a good thing.
 
The connectors must be of the same thermal couple materials if you need to replace them
 
One thing i have done is place the connector(any type tc) in a ziplock bag with a gob of silicone in it. then form the silicone around the connector. Leave sit for a few days. Then remove the bag.I have done this with many different mfg connectors. I have some that have been in direct weather for years and still look new.

Simple fixes for my simple mind

good luck,Joe
 
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