Temperature Sensor

Oowww that's a tricky one. I assume as the wire is so small and its moving so fast 18 metres a second?!! that you can't have any contact with the wire?

Also, what temperatures are you expecting to find?

Its possible to do using a miniature infrared sensor, but it would have to be calibrated in-situ...

John.

Only thing that makes sense to me is either an infrared camera or infrared thermometer which are used for indirect measurement of point (thermometer) or area (camera) temperatures. The response time may be a problem with your fast moving target, looks like about 500ms for thermometer (not sure about the camera).

Camera may be the better option. What temperature and temperature changes are you expecting? That will help narrow down the options a bit.

Do you know what is commonly done in the industry?

I agree with ELectroman it would have to be calibrated in-situ.

Interesting concept used by MAF (mass air flow) sensors: A wire is heated (by electricity) controlled by the engine's computer. It tries to keep it a certain temperature, but as the air passes around the wire it cools, making the ECM increase the electric flow to keep the set temperature. The computer monitors the increase and decrease.

I wonder how those wires are heated? Could you have a a few rollers or "whiskers" contact the wire and induce a small current and then measure the difference with other rollers along the way (after calibration)?

How about passing the wire through a very small diameter metal tube that was insulated on the exterior? You could then measure the surface temperature of the tube with a thermocouple placed under the insulation. The tube should be as long as possible to reduce error from heat loss to the atmosphere. This wouldn't give you an accurate enough answer for tight control purposes, but would certainly reflect the wire temperature. I'd try thermocouples at several different locations to check error. You might be able to calibrate this with a stationary heated wire.

I only guess that this wire comes out of a copper conductor drawing machine.

If so your best bet might be IR non contact measurements, as has already been suggested, but due to the high relative speed I foresee calibration and pulling problems.

Why don't you think about spectrophotometry, done inside a light proof enclosure That will allow you more accurate measurements, without the problem pulling affect you may encounter with point measurements. What level of accuracy are you looking for? By using interchangeable orifices, you will be able to measure practically any size wire coming out the drawing process. Take heed! this IS an expensive solution...

Wangito