Armour wires have different coaxial metallic layers to improve electrical return efficiency

摘要

The cable 50 includes an electrically conductive cable core 41 for transmitting electrical power and at least one layer 54, 55 of a plurality of armour wires surrounding the cable core. At least one 51 of the armour wires is a bimetallic armour wire having a coaxial inner portion and a surrounding outer portion. The inner and outer portions are formed of different metallic materials and the bimetallic armour wire provides a return path for the electrical power transmitted through the cable core. The inner metallic material may be chosen from copper, aluminium or beryllium-copper; the outer metallic material may be chosen from the alloys MP35N, HC-265, Inconel, Monel or Rene.