I have a big toroidal transformer that I removed from an old navigational simulator. (Image)
There's a label on the side, Ulveco N12981 EMI 1271 but I can't find any datasheets.
It weighs about 8Kg (18 pounds) and with a 220V AC input I measured:
Green - Yellow : 112V
White : 277V
Gray : 337V
Black - Green : 112V

What would be the best use of this transformer?
Would it make any sense to rewind this thing?

 

I have a big toroidal transformer that I removed from an old navigational simulator. (Image)
There's a label on the side, Ulveco N12981 EMI 1271 but I can't find any datasheets.
It weighs about 8Kg (18 pounds) and with a 220V AC input I measured:
Green - Yellow : 112V
White : 277V
Gray : 337V
Black - Green : 112V

What would be the best use of this transformer?
Would it make any sense to rewind this thing?

Be careful how you mount it - a surprisingly large number of people create a shorted turn strapping them to the chassis.

 

They are my choice as you can wind on any secondary configuration you need very easily, within the (K)va rating.
Max.

 

You could make a healthy-size DC power supply with it.

 

Ulveco made good quality transformers. I believe the company was swallowed by another. Many of their products were custom made so finding data may be impossible. You can estimate power rating from weight in comparison with other iron-core toroids, but ratings of individual windings require access to the wire. Some of their transformers simply brought out the winding wire as the leads. From the photo the leads appear to be stiff, so that may well be the case. Typically windings with the same voltage could be connected in parallel or series, but some care is required to verify they can be connected in parallel.

One or two turns of heavy welding cable as a secondary would make a pretty capable spot welder.
You might connect the 112 volt windings in series and use it as an isolation transformer.

 

Question: are they in phase? If not, what is the phase shift? Do you have a scope?

 

"Question: are they in phase?"

Of course they are in phase or 180 degrees out of phase, which means they are brought into phase by reversing the leads on the winding in question. How on Earth could they be otherwise? (ignoring the very small shifts that do occur in iron core transformers due to magnetic hysteresis)

 

Maybe there could possibly be some weird wiring with additional series inductance or something. I guess it was kind of a stupid question.

 

You could probably make a reasonable estimate of each winding's current capability by measuring the winding resistance and assume something like a 5% drop in voltage at the maximum current.

 

Do you have any kind of remote thermal imaging thing? A laser thing or thermal camera? If so, try gradually increasing the load and stopping when it gets really hot. If it is not hot, then it can probably handle the power being dissipated.

 

Going by the picture and Toroidal purchases I have made over the years, I would put it at 1Kva easily.
Max.