The nameplate sometimes will tell you if it is an aluminum winding.
A transformer that contains $30K of copper would have to have at least 10K lbs of copper in it. I'm thinking your transformers will yield maybe 30% of their weight in copper....as a "SWAG" guess. So you might see 10K lbs of copper out of all three.
You will have to "de tank" them to pull out the internal windings--nip the row of bolts around the top with a torch and lift out the
core and coils.
You will now be able to tell for sure if it is copper or aluminum windings. I've heard that some transformers can be aluminum for one winding and copper for the other, so check both the primary and secondary windings.
I'm assuming you have already checked them for resale as transformers? There is a market for large transformers--lots of big outfits take them out of service a fair length of time before they need to for reliability reasons.
Hope this helps,
Jon.
Bookmarks