Why do people keep comparing copper and aluminium in transformers?
For many years, copper was regarded as the benchmark material for transformer manufacture, thanks to its excellent electrical conductivity and reliability. However, with the evolution of production technologies and manufacturing processes, aluminium has also established itself as a high-performance solution, and is now one of the most widely used materials in the manufacture of dry-type transformers. The choice between copper and aluminium continues to be a subject of debate today, from both a technical and an economic perspective
Is copper more efficient than aluminium?
The efficiency of a transformer does not depend solely on the material used for the windings, but on the overall design. Copper and aluminium have different physical properties that require specific design approaches, but both allow for the production of highly efficient transformers.
For example, an aluminium winding requires a larger cross-section than a copper one, whilst copper generally allows for a more compact design. However, these differences are already taken into account during the design phase, by optimising the geometries, dimensions and characteristics of the magnetic circuit to achieve the required performance objectives.
For this reason, given the same technical specifications, both a transformer with copper windings and one with aluminium windings can guarantee equivalent levels of efficiency.
Do safety and electrical performance differ?
From the point of view of safety and electrical performance, there are no substantial differences between transformers with copper and aluminium windings. In both cases, it is possible to manufacture equipment capable of guaranteeing high levels of reliability, efficiency and continuity of service.
As with energy efficiency, the electrical behaviour and the maximum temperature reached during operation are also essentially equivalent. In modern cast-resin transformers, it is the design of the windings, the quality of the insulating materials and the manufacturing technologies employed that determine most of the performance, rather than the conductor material used.
What is the real difference between copper and aluminium in terms of operational performance?
Which type should I choose?
In light of the characteristics analysed, there is no single material that is universally superior to another. Both copper and aluminium can be used to produce efficient, reliable and durable transformers.
The choice depends on various factors, including the application, operating conditions, any overload requirements, the space available and the project’s cost considerations.
At TMC Transformers, we design and manufacture medium- and low-voltage power transformers using dry-type technology, assessing on a case-by-case basis the design solution best suited to the customer’s needs. Our design expertise enables us to identify the most efficient, reliable and cost-effective configuration for each specific application