World's First Full-Scale High Temperature Superconductor Degaussing Cable for Military Ships

American Superconductor Corporation, WASHINGTON: American Superconductor Corporation, a leading energy technologies company, today announced at the annual U.S. Navy League Sea-Air-Space Conference — the premier gathering for presenting new naval technologies — the successful demonstration of the world's first full-scale superconductor-based degaussing cable. 
 
Degaussing cables are utilized in most navy ships to reduce their magnetic signature, thereby making them much more difficult to be “seen” by magnetic sensors and specifically by magnetically activated mines. The HTS degaussing cable that was demonstrated — a proprietary AMSC design that incorporates AMSC's high temperature superconductor (HTS) wire — is 142 feet (40 meters) long. The cable produced 4,100 Amp-turns — a typical level of performance of conventional copper-based degaussing cables deployed in military ships today — with a significant decrease in operating voltage to less than 0.5 volts, or 1000 times lower than copper-based systems. 
 
Importantly, the HTS degaussing cable is only 20% of the weight of conventional degaussing cables. The substantial reductions in weight, size and number of terminations are expected to yield a reduction in total installed cost of 40% compared with degaussing systems based on copper. In addition, because of the zero electrical resistance of HTS wires, less energy is required to run HTS degaussing systems. 
 
According to Mr. Brian Fitzpatrick, Project Engineer at the U.S. Naval Surface Warfare Center (NSWC), in a paper he delivered at American Society of Naval Engineers Day 2005: “Replacing the copper conductor cabling in a typical degaussing system with a superconducting cable offers the potential benefits of both reduced conductor weight and reduced number of conductor turns. The reduction in cable size that is possible with the superconducting cable will provide additional benefits since, for most degaussing loops only one physical turn of its flexible cryostat is required. Installation benefits are also achieved with reduced power supply electrical requirements and reduced size and weight of power supply system.” 
 
AMSC produces HTS wires today that conduct more than 150 times the electrical current of copper wires of the same dimensions. For a typical military ship such as the U.S. Navy's LPD 17 class amphibious warship, this “power density” advantage means the HTS degaussing systems will weigh 20% of the weight of an advanced copper-based degaussing system — yielding not only a significant reduction in system weight, but also in installed cost. 
 
Degaussing cable systems currently represent a worldwide annual addressable market of $100 million. They are utilized in virtually all of the world's naval vessels. 
 
“Our HTS wires are a platform technology that are creating product opportunities in multiple markets and industrial sectors around the world because of their distinct advantages in power density and electrical efficiency,” said Greg Yurek, AMSC's chief executive officer. “In addition to lighter weight and lower cost degaussing cables, we have also been developing much lighter weight, smaller volume, much more energy efficient HTS ship propulsion motors for the U.S. Navy. We expect to deliver the first 36.5MW HTS ship propulsion motor to the Navy in September 2006.” 
 
The 142-foot (40 meter) long HTS degaussing loop developed by AMSC is based on a proprietary cabling technique that allows the wires to remain flexible within their containment jacket and conform to installation requirements for integration into typical naval ships. The cables are housed in commercial cryostats that provide the necessary thermal insulation to allow the cable to operate at needed temperatures. The cable is cooled by AMSC's patented gas circulation system utilizing a commercial refrigerator. In addition to its physical advantages, an HTS-based degaussing system will offer significantly lower reactance relative to equivalent copper cable systems. This characteristic, in turn, will offer improved performance relative to current systems in use today.  
 
AMSC is the world's principal vendor of high temperature superconductor (HTS) wire and large rotating superconductor machinery, and it is a world-leading supplier of dynamic reactive power grid stabilization products. AMSC's HTS wire and power electronic converters are at the core of a broad range of new electricity transmission and distribution, transportation, medical and industrial processing applications, including dynamic reactive power grid stabilization solutions, large ship propulsion motors and generators, smart, controllable, superconductor power cables and advanced defense systems.