Additively Manufactured Polymer Composites for Superconducting Motor Coil Structures

The Robinson Research Institute at Victoria University Wellington is building a series of superconducting motors over the next six years to demonstrate technology pathways for the transport industry, including aviation. Our target topology for these machines uses rotor-mounted superconducting field coils and a superconducting stator in an air-core configuration. To avoid eddy current heating in the stator cryostat, electrically conductive materials must be eliminated. At the same time, heat generated due to AC losses in the stator must be transferred efficiently and evenly from the superconductor to the cryo-coolant, in order to avoid localised film boiling. And finally, the coil structural support needs to closely match the thermal expansion characteristics of the superconductor wires and likely other G10 structural pieces to avoid debilitating stresses and lost support.In this study, we investigated the opportunity to use additively manufactured (AM) polymers with a range of filler materials as the structural support for a motor coil. A range of commercially available candidate materials have been identified and test coupons manufactured using either Selective Laser Sintering (SLS) or Fused Deposition Modelling (FDM). The material properties of the test coupons have been measured from room temperature down to cryogenic temperatures. This data was used to design, analyse and manufacture the support structure for a stator saddle-coil, and the coil wound with aluminium wire to simulate Conductor on Round Core (CORC) cable. Initial thermal cycle testing has been carried out to assess the performance of the composite.