thermocouple ID

[isw]

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

[whit3rd]

On Wednesday, June 3, 2015 at 9:35:43 PM UTC-7, isw wrote:
> I have come across a thermocouple that I can't identify....

> 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.

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.

[Phil Allison]

isw wrote:
>
> I have come across a thermocouple

** Where you found it is a big clue.

> 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).

** 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

[isw]

In article <38f5b7b5-fc2e-4d61...@googlegroups.com>,

Phil Allison <palli...@gmail.com> wrote:

> isw wrote:
> >
> > I have come across a thermocouple
>
> ** Where you found it is a big clue.

Came with the meter -- both from eBay.

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

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

[Phil Allison]

isw wrote:


> > >
> > > I have come across a thermocouple
> >
> > ** Where you found it is a big clue.
>
> Came with the meter -- both from eBay.

** That's a big clue.

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

** Then it is high time you did.

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

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

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

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




... Phil

[isw]

In article <eaa92ec0-0f8d-48f4...@googlegroups.com>,

Phil Allison <palli...@gmail.com> wrote:

> isw wrote:
>
>
> > > >
> > > > I have come across a thermocouple
> > >
> > > ** Where you found it is a big clue.
> >
> > Came with the meter -- both from eBay.
>
>
> ** That's a big clue.

To what?

> > > > 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).
> > >
> > >
> > > ** You don't have a K-type pre-amp/adaptor or a DMM with one to try it
> > > out ?
> >
> > Sure do.
>
>
> ** Then it is high time you did.
>
> > But how can the meter part tell me what the thermocouple
> > materials are, if I'm not sure about the calibration of the adapter?
>
>
> ** What does it read at room temp or when immersed in boiling water ?

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

[Phil Allison]

isw wrote:

> > > > >
> > > > > I have come across a thermocouple
> > > >
> > > > ** Where you found it is a big clue.
> > >
> > > Came with the meter -- both from eBay.
> >
> >
> > ** That's a big clue.
>
> To what?

** That the two items are matched.

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

** 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