Copper Contributes to Big Engines that Can
Copper is helping the railroads gain market share from long-haul truckers. More than eight tons of copper in each of the latest, most-powerful locomotives enables them to pull longer trains faster up steeper grades.
The latest advance in this use of copper is the substitution of AC-induction drive motors for DC drive motors. To gain higher efficiency and tractive effort, fabricated copper conductor bars are specified for the rotors of these three-phase motors instead of aluminum. (The rotors of the vast majority of induction motors for all uses are made by die casting aluminum.) The stators (stationary part) of all motors are wound with copper wire.
These technically advanced locomotives are also more reliable, more efficient and more resistant to environmental extremes than the prior generation of locomotives with DC drive motors. America's two manufacturers of locomotives, General Electric and General Motors, developed AC-induction drive motors several years ago. Today, this technology is enabling them to introduce units with six drive motors that will generate 6,000 or more horsepower, 50% more powerful than prior models with DC drive motors. GE still offers smaller locomotives with DC propulsion systems.
AC Motors Last Longer
Besides ensuring greater tractive power on the order of 30% and more, the new AC-induction drive motors are expected to last much longer than DC drive motors, according to N. Richard Dunteman, general director, Advance Technologies & Locomotive Systems, GM Electro-Motive Division, LaGrange, Illinois. The six one-hp AC-Induction motor in the latest GM locomotives are powered by big AC alternator in turn driven by a single 16-cyclinder diesel, which also drives a smaller auxiliary generator. All the copper in GE's and GM's drive motors, main and auxiliary generators and cabling is high purity, electrolytic tough pitch copper, C11000. In the GM locomotives, each rotor contains 330 pounds of copper and each stator uses 410 pounds. The copper in the main generator weighs 2,550 pounds while that in the auxiliaries weighs 525 pounds.
Five Miles of Copper Cable
In addition to all the copper in the propulsion system, there's more than 27,000 feet of copper power and communications cable in each GM locomotive, including the heavy duty cables linking the induction motors to the braking system. About the same amount is in GE's largest locomotives, according to Bruce Colton, product planner for GE Transportation Systems, Erie, Pennsylvania. The crew compartments are equipped with refrigerators, hot plates, air conditioning and heating, which require more copper.
The 16-cylinder diesels in both GE and GM locomotives are water cooled with big radiators made of copper tubing (silver-bearing tough-pitch C11300 for GM) cooled by fans with copper-wound electric motors. The radiators in GE's locomotives are made of an alloy containing 80% copper and weigh between 3,000 and 5,000 pounds each, depending on the model.
In each of the next few years, the nation's railroads are expected to buy some 800 of the new GE or GM locomotives, which cost about $2 million apiece. That translates into an annual requirement of 12.8 million pounds (6,400 tons) of copper or high-copper alloys.
... and to Small Engines that Can
Copper in many forms is also used in the fabrication of model trains. Locomotives and rolling stock in all scales are cast in solid brass. Such models are highly prized by model railroaders and collectors. The motors are wound of copper wire as are the transformers that reduce the voltage applied to the tracks to a low, sage level.
Model railroad tracks are made of either brass or nickel silver, another alloy of copper. How much copper is consumed each year in the manufacture of toy and model trains? It's likely to be no more than the 8 tons in each of the latest electric locomotives from GE of GM.
GE Transportation Systems: 814/1875-2234
GM Electro-Motive Division: 708/1387-6000
Also in this Issue:
- Copper Contributes to Big Engines that Can
- "Old Ironsides" Still Protected by Copper
- More Copper Makes More Space
- Copper Clues to Golden Treasure