This white paper focuses on the two metals that offer high electrical conductivity at economically viable prices: aluminium and copper. It points out that silver is a superior conductor, while gold isn't. In any case, the high prices of silver and gold makes their use in cables, wires, conductors and electrical machines uneconomical.
The author – Stefan Fassbinder from the German Copper Institute – makes a careful analysis of the requirements of different electrical applications such as low- and medium-voltage cables, overhead high-voltage cables, transformers, busbars and rotor cages. For each one he analyses the suitability of both aluminium and copper in terms of technical performance and financial considerations.
The paper presents and discusses some pertinent questions. Why in Western Europe is aluminium hardly ever used in the manufacture of electrical machines? Why are electrical machines using copper lighter and more compact than aluminium designs (for the same efficiency)? Why do European standards not permit the use of aluminium conductors with cross-sections up to 16 sqmm (or in some cases) up to 10 sqmm? Thankfully the author provides comprehensive and well thought-out answers.
Also considered – although more briefly – are the merits of non-metal conductors. Leaving aside semiconductors like germanium and silicon, the paper describes the relevance of carbon for carbon brushes, liquid conductors for electrochemical applications, electrically conducting polymers, superconductors, and even the rather futuristic concept of nanotubes.
“Practical applications of electrical conductors” will provide clear and useful guidance to electrical engineers, design engineers and electrical engineering students struggling with the question “Copper or aluminium – Which one to use and when?”