without color coding, without nameplate, without multimeter
how can you find the type of thermocouple???



without color coding, without nameplate, without multimeter how can you find the type of thermocou..

Answer / carl_ellis

Let's assume base metal elements only, since noble metal
elements are so expensive that they are under lock and key;
adequate protection from loss of identification.

For types T, J and K, (and by exclusion, E) the options are

-a spectropscopic assay which will positively reveal the
alloys' composition, but given that the cost of an assay is
proabably 20x times the value of a base metal element, it's
not likely to happen.

- visual identification of a type T by the copper color of
its positive leg which is copper. The alloy leg is a shiny
'metallic' color.

- testing Types J or K with a magnet.
The Type J positive leg is made of iron which has a very
strong magnetic attraction.
The Type K negative leg is made of a nickel alloy which is
mildly magnetic.
Type E is non magnetic, but so are other types.
It can be tricky to distinguish mild attraction on thin
gauge wire.

Testing with a multimeter can be very misleading, because of
the difficulty in determining both the hot junction AND the
cold junction temperatures. Without accurate temperature
values, of what use is a mV reading?

Carl Ellis
Measure First

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