Superconducting Synchronous Motors for Electric Ship Propulsion

This paper develops a notional design for a 36 MW, 120 rpm motor for ship propulsion. The design exhibits high torque density (66 Nm/kg) and high efficiency (99%). This synchronous motor uses LTS (low temperature superconducting) field coils to create a minimum of 2 T magnetic field in the air gap of the motor. The motor is substantially lighter, more compact, and far more cost effective than other compared approaches. A significant feature of the LTS motor is reduction in radial forces between the field and armature by two orders of magnitude compared to a conventional motor. The motor promises significant cost and performance improvement. Conductor requirements, options, and electromagnetic features such as quench protection and cryogenic support options are discussed.