American Superconductor Corporation recently announced the successful completion of factory acceptance testing for the world's first 36.5 megawatt (49,000 horsepower) high temperature superconductor (HTS) ship propulsion motor at Northrop Grumman's facility at the Philadelphia Naval Business Center. This is the final milestone before the Navy takes possession of the motor.
The motor was designed, developed and manufactured under a contract from the U.S. Navy's Office of Naval Research (ONR) to demonstrate the efficacy of HTS primary- propulsion-motor technology for future Navy all-electric ships and submarines. The power and torque of this HTS motor is comparable to the requirements for the Navy's new Zumwalt class of destroyers, known as DDG 1000. In comparison with the conventional copper motors being used on the first two DDG 1000 hulls, the HTS motor is less than one-half the size and weight, and is more efficient over a much wider range of ship speeds. This results in weight and space advantages, enabling an increase in payload capacity for both naval and commercial vessels.
Why HTS?High Power Density: The HTS field winding produces magnetic fields higher than those of conventional machines resulting in smaller size and weight.High Partial Load Efficiency: HTS motors have higher efficiency at part load (down to 5% of full speed), that results in savings in fuel use and operating cost. The advantage in efficiency can be over 10% at low speed.Low Noise: HTS motors have lower sound emissions than conventional machines.Low Synchronous Reactance: HTS air-core motors are characterized by a low synchronous reactance which results in operation at very small load angles. Operating at a small load angle provides greater stiffness during the transient and hunting oscillations.Harmonics: HTS motors generate voltages free of harmonics.Cyclic load insensitivity: HTS motor field windings operate at nearly constant temperature unlike conventional motors and, therefore, are not subject to thermal fatigue.Maintenance: HTS motors compared to conventional motors will not require the common rotor overhaul, rewinding or re-insulation.(Source: American Superconductor)