How to distinguish whether a dry-type transformer is a copper core or an aluminum core?

1. The model number on the transformer inscription.

If it is an aluminum coil transformer, there should be an L symbol, but a copper coil transformer does not have this symbol.

2. From the appearance.

Aluminum coil transformers are slimmer (taller), while copper coil transformers are chunkier and larger overall.

3. Weight.

Because aluminum has a specific gravity of 2.7, while copper has a specific gravity of 8.9.

4. In addition, from a technical point of view, there is no problem with aluminum coils for dry-type transformers cast with epoxy resin, but they are better. Because the expansion coefficient of aluminum is closer to the expansion coefficient of epoxy resin than copper, the reliability of the transformer is better. Therefore, in Europe, most epoxy resin cast transformers use aluminum coils.