Cables, electrical copper/aluminum

Calcium has a number of practical uses—as a deoxidizer (substance removing oxygen) for iron and steel and for copper and copper alloys, as a constituent of lead alloys (metal for bearings, or the sheath for electric cables) and of aluminum alloys, and as a reducing agent for making other metals from their oxides. 

Metals are unique in that they can conduct electric current in the solid state. (Examples include aluminum high voltage transmission cables and copper... 

Even though aluminum doesn t conduct electricity as well as copper, it costs less to use aluminum than copper for transmission of electricity. Aluminum cables are much lighter than copper cables, so fewer support towers are needed to hold the miles and miles of cable that span the country. Fewer support towers means lower cost for all consumers of electricity. 

Metals such as copper and aluminum are good conductors of electricity, but they do possess some electrical resistance. In fact, up to about 20 percent of electrical energy may be lost in the form of heat when cables made of these metals are used to transmit electricity. Wouldn t it be marvelous if we could produce cables that possessed no electrical resistance ... 

The electrical resistance of aluminum is 1.5 times that of copper however, its density is only 2700kgm compared with 8900kgm for copper. Hence the conductivity of aluminum is twice that of copper per unit weight. It is therefore used widely for power transmission cables. Aluminum is in general more resistant to corrosion than iron and steel owing to the formation of a well-adhering coating of aluminum oxide. 

Indium has many industrial uses for electronics and electrical applications [9] indium metal in germanium transistors indium alloys for soldering and glass sealing of electronic devices indium antimonide, arsenide, and phosphide in infrared detectors and semiconductor applications indium-silver alloys for brazing and electroplated indium metal for electrical connectors. For underground telephone cables, indium has been used to plate copper-to-aluminum connectors. About 2-5 tons of indium alloyed with silver and cadmium has been used annually in nuclear reactor control rods. 

There are alternative materials with which copper has to compete. Aluminum substitutes for copper in electrical power cables and in refrigeration tubing. Titanium and steel are alternatives in heat exchangers. Plastics substitute for copper in water pipes, and optical fibers in telecommunication apphcations. 

For electrical wire and cables, the combination of conductivity and low weight is very important. In the metallurgical industry, aluminum is used as a deoxidation agent in steel manufacturing (see Chapter 8 Iron) and as an alloying element in magnesium, titanium and copper alloys. 

The estimated consumed power of reclaim water pumps and booster slurry pumps is supplied to the electrical engineer. Power is brought to the mining site using 10 kV or 14.6 kV overhead or underground lines. Overhead transmission lines may be of an aluminum conductor, steel reinforced (ACSR). Underground cables may be made of aluminum or copper. On-site power generation is sometimes considered. 

PCAD mass is dominated by the cabling from the alternators to the spacecraft bus. Table 4-3 shows estimates of the PCAD cabling for the various system architectures. In each case, the cabling mass was calculated assuming a 3% electrical loss. Conductors are copper and the mass excludes insulation. Use of aluminum conductors is estimated to reduce these conductor masses to approximately 41% of the mass shown in Table 4-3. 

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