To identify whether a transformer winding is made of copper or aluminum, you can use a few different methods:

  1. Visual inspection: Copper windings are typically reddish or brownish in color, while aluminum windings are silver or gray.
  2. Weight comparison: Copper is much denser than aluminum, so a copper winding will be heavier than an aluminum winding of the same size.
  3. Conductivity test: Copper has a higher conductivity than aluminum, so you can use a conductivity meter to test the conductivity of the winding material.
  4. Magnet test: Copper is not magnetic, while aluminum is slightly magnetic. You can use a magnet to see if it is attracted to the winding material.

It’s important to note that these methods may require some expertise and caution, especially when dealing with high-voltage transformers. If you’re unsure, it’s best to consult with a professional or a qualified technician.