1. Home
  2. Electronics Repair
  3. thermocouple ID

thermocouple ID

I have come across a thermocouple that I can't identify. From other factors, I suspect it is a type K, but that's what I want to confirm (because if it's not, the temperatures will be wrong).

All insulation is glass fiber, or something just like it (makes you itch). The sheath is woven but not varnished and appears to be all white. The positive wire is white with a blue (or black??) tracer, and is not magnetic. The negative is white with a red tracer, and is magnetic.

I've looked at a lot of documents on line that list a whole lot of color combinations, but nothing I've found matches what I have.

Any ideas?

Isaac

Reply to
isw
Loading thread data ...

Put one end in icewater, the other in boiling, and expect type J: 5.26 mV type K: 4.09 mV type E: 6.32 mV type T: 4.28 mV

T, at least, is very unlikely; neither wire ought to be magnetic. Type J definitely has one wire magnetic. It's usually red vs white.

Reply to
whit3rd

** Where you found it is a big clue.

** You don't have a K-type pre-amp/adaptor or a DMM with one to try it out ?

Then how do you propose to use the thing?

BTW you will need a K-type two pin plug, normally yellow colour.

.... Phil

Reply to
Phil Allison

Came with the meter -- both from eBay.

Sure do. But how can the meter part tell me what the thermocouple materials are, if I'm not sure about the calibration of the adapter?

As I said, it was represented to be a type K, but the color codes don't match anything I can find.

Isaac

Reply to
isw

** That's a big clue.

** Then it is high time you did.

** What does it read at room temp or when immersed in boiling water ?

** As you must have found, thermocouple colour codes vary from country to country. It don't matter a hoot.

... Phil

Reply to
Phil Allison

To what?

Dead nuts at 100C, about 3-4 C high in a water-ice slurry.

From what I read, it would be easy to use, say, a type J t-couple and do a two point calibration that would seem OK (there are two pots in the meter) but other temperatures would be incorrect, and the cold-junction compensation would be wrong.

And that's why I'm trying to find out what the colors mean.

Isaac

Reply to
isw

** That the two items are matched.

** If the negative wire is slightly magnetic, you have a type K made with Nickel Aluminium alloy.

Type Js have a strongly magnetic iron positive wire.

.... Phil

Reply to
Phil Allison

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.