The Hunt for Compact Power

This article explains features of a ship propulsion motor with superconducting coils that hushes machinery noise and hollows out confined engine rooms. American Superconductor Corp. of Westborough, MA, announced plans to build a high-capacity manufacturing plant for its superconducting wire. This will move the company’s high temperature superconductor (HTS), wire from a developmental phase into large-scale production. IPS is exploring more than just propulsion motor technology. Engineers are evaluating the entire shipboard electrical system, from ship’s service power, to dc distribution, to power electronics—as well as the propulsion motor itself. The Navy, having decided upon electric drive for its next warship, has left the door open for superconducting motors. Superconducting motors can develop the same torque and horsepower within a motor frame that is nearly a third the size of a comparably rated conventional motor. The main factor leading to an HTS motor’s smaller size for a given horsepower output is the magnetic field strength that superconducting magnets create. Iron teeth, used to enhance magnetic flux in conventional rotors and stators, are not needed by superconducting motors.