American Superconductor (AMSC) has recently announced the successful completion of 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 under contract to the US Navy’s Office of Naval Research (ONR). Its power and speed rating are typical to copper-based electric propulsion motors that are currently used in various commercial ships. This new class of superconductor motors is expected to become a standard for certain military ships. AMSC built the superconductor rotor assembly, including the rotor refrigeration system, for the 5 MW motor. The company’s subcontractor on the project, ALSTOM’s Power Conversion Business, designed and built the copper-based, liquid cooled stator and assembled the motor in its Rugby factory (UK), where the motor has successfully undergone no-load testing. The next stage of testing, which will be under full load, is expected to be completed in June. The 5 MW motor is now being integrated with an ALSTOM VDM 5000 commercial power electronic drive and a dynamometer for load testing. This test will confirm full torque and full speed under load.

According to industry experts, the current annual global market for electric motors and generators utilised for electric propulsion in commercial cruise and cargo ships is over $400 million. The market for ship propulsion motors is expected to grow rapidly to over $2 billion per year by 2010 because electric drives are becoming the propulsion system of choice for both commercial and military ships.