Permanent Magnet Motor Steering Gear for DDG 51 FLT IIA

Permanent Magnet Motor (PMM) technology, already used in demanding applications by the U.S. Navy and by the oil drilling industry, may be expanded to replace electro-hydraulic steering gear on DDG 51 class ships. PMM steering can potentially provide suchbenefits as improved dynamic performance, reduced noise emissions, lower maintenance, higher reliability, and lower life cycle cost.The challenge in using a PMM as a rudder actuator is the requirement for very high torque at very low rotational speeds. This proposal describes three alternative PMM steering gear configurations that will meet this requirement. Each of theseconfigurations will be evaluated on the following criteria: technical feasibility, dynamic performance, development cost, production cost, environmental standard compliance, power consumption, maintainability, and reliability. This evaluation will leadto recommendation of a PMM steering gear configuration for the DDG 51 FLT IIA. Commercially viable PMM steering gear will be of great interest to commercial and military shipbuilders. This research could also lead to improvements in PMM propulsionsystems and other high torque PMM applications.