American Superconductor Corporation has completed a no-load factory testing for the world's first high temperature superconductor (HTS) electric ship propulsion motor. The company's ultra-compact HTS motors are as much as half the weight, one-third the size, operate with higher fuel efficiency and have lower maintenance costs than equivalently priced copper- based motors at the same power and torque rating. The patented 5 megawatt (MW), 230 rpm HTS propulsion motor was designed by AMSC's SuperMachines(TM) business unit under contract to the U.S. Navy's Office of Naval Research (ONR). Its power and speed rating are typical for copper-based electric propulsion motors that are currently used in ferries and small cargo ships around the world. This class of superconductor motors also is expected to become a standard for certain military ships.