February 20, 2002
ONR orders HTS superconducting propulsion motor
American Superconductor Corporation has been awarded an $8 million contract by the U.S. Navy's Office of Naval Research (ONR) to build and deliver a 6,500 horsepower (hp) high temperature superconductor (HTS) motor designed for ship propulsion. The contract represents the fourth ONR contract with American Superconductor focused on developing HTS motor technology for future Navy electric warships.
Under the ONR program, American Superconductor will deliver a factory-tested AC synchronous HTS motor, integrated with a commercially available power electronic drive system that will be suitable for shipboard at-sea trials. The 6,500 hp motor developed under this contract will operate at 230 revolutions per minute (rpm) providing a ten-fold increase in torque over a 5,000-hp, 1,800rpm HTS motor AMSC built and tested during 2001 (
The low-speed, high-torque 6,500 horsepower HTS motor is seen as a critical development milestone on the path to 20,000-hp and 35,000-hp motors, which are the power ratings expected to be utilized on electric warships and on large cruise and cargo ships. HTS motors of these power ratings are expected to be as little as one-fifth the volume of conventional motors.
"This is the first HTS motor designed specifically for ship propulsion,'' said Greg Yurek, chief executive of American Superconductor. "The increased power density and efficiency of our proprietary HTS motors allow ship designers to create new types of ships not possible with conventional motor technology. Our previous HTS motor projects have brought us to the point where we believe the technology is ready to demonstrate in an actual ship installation. The contract calls for delivery of the motor to the Navy in the summer of 2003, enabling sea trials before the end of that year. We believe we are on track to be producing similar HTS motors for commercial sale in 2004.''
Diesel-electric LNG tanker
There are a number of innovative features in an LNG ship ordered by Gaz de France this month. The order for the 74,000 cu m LNG carrier was placed with Chantiers de l'Atlantique and includes an option for a second vessel.
The ship will have the following dimensions
Overall length : 219, 5 m
Breadth : 34,5 m
Total installed power : 19,000 kW
Speed : 18.5 knots
It will fly the French flag and will be operated by Gaz de France affiliate Gazocean.
It will have four membrane-type cargo tanks utilizing a new insulation system developed by Gaztransport and Technigaz (GTT), in which Gaz de France has a 40% ownership stake.
Classification society Bureau Veritas helped develop the concepts for the vessels, and developed unique new rules to allow the yard and owners to break new technological frontiers.
"BV has consistently been the world leader in LNG carriage, since development of membrane LNG carriers was first begun," says Bruno Dabouis, commercial manager of BV's marine division. "Now we will class these new vessels, which are a quantum leap forward in cost-effective LNG transportation. The innovative features in these ships will set the benchmark for the rest of the world to live up to."
The ships have two key innovations. The traditional steam turbine plant will be replaced by a low-pressure dual fuel diesel electric system, and the cargo gas will be carried in the new GTT CS1 membrane system.
BV developed the safety concept for the low-pressure dual fuel diesel/gas engine, and has issued new rules for such engines. These are unique, and set new standards for this type of machinery plant.
BV's consultancy division, Tecnitas, worked with GTT on the complex calculations and modelling needed to develop the cost-effective CS1 containment system. CS1 was granted BV concept approval earlier this month.
The dual fuel diesel electric propulsion system offers several advantages. As a more compact installation, it allows the shipyard to maximize cargo space in the hull. It will reduce gas consumption compared to the conventional turbine installations. Operators will have more flexibility with respect to crewing, as engineers familiar with turbine installations are now in short supply.
Maintenance is simplified as generator sets can be taken of line and maintained on passage. Machinery redundancy is enhanced, cutting the risk of a power failure.
The CS1 containment system combines the best features of the proven Mark III and NO96 membrane systems. It offers increased strength, faster fabrication, and a cost reduction of 15 per cent compared to existing systems. Partial loading conditions are also possible, improving operational flexibility.