I have a small transformer with a load applied...how do I measure the temp from the wiring/windings?

Answer 1

Funny you should ask, I'm doing exactly that at the moment. I have 2 thermocouples on each transformer, one touchng the windings and another taped to the core. I have a Fluke 2-channel digital thermometer, and every few minutes, I'm taking reading. I have loads equivalent to what they will see in the system, and the goal here is to get the new version of the transformer UL approved.

Thermocouples, that's the ticket.

Answer 2

If this is a practical problem, the only realistic solution is probably going to be a thermocouple type probe inserted under the winding.

If it is an academic exercise, then you could suggest trying something like this:

Measure the d.c. resistance of a winding when the transformer is at room temperature,

Measure the room temperature.

Measure the d.c. resistance when it is still hot from being on line.

Use the temperature coefficient of resistance of copper to estimate the change in temperature.

In practical terms, you would have to be able to measure the resistance incredibly accurately, but it's the sort of suggestion that goes down well with people who do not have to actually do it.