Homopolar machine with shaft axial thrust compensation for reduced thrust bearing wear and noise

A homopolar machine comprising:

• a shaft;
• an armature assembly, coupled to the shaft, that includes a plurality of armature conductor turns;
• and
• a plurality of stator-current collector arrays that encircle the armature assembly, each stator-current collector array including a plurality of current collectors that maintain substantially constant contact pressure with the armature conductor turns in the presence of a high magnetic field to provide a sliding electrical current interface with the armature conductor turns;
• wherein the plurality of stator-current collector arrays is oriented such that the high magnetic field is substantially parallel to a direction of current flow in a region where at least one of the plurality of stator-current collectors contacts one of the armature conductor turns to reduce induced magnetic forces that may deflect the current collector.

A method of operating a homopolar machine, comprising the steps of:

• rotating a plurality of armature assemblies that include a plurality of armature conductor turns;
• creating a magnetic field through the plurality of armature assemblies;
• providing a plurality of stator-current collector arrays that encircle the plurality of armature assemblies, each stator-current collector array including a plurality of current collectors which provide a sliding electrical current interface with the armature conductor turns;
• reducing induced magnetic forces that may deflect the current collectors by directing magnetic field lines substantially parallel to a direction of current flow in a region where at least one of the plurality of current collectors contact the armature conductor turns;
• and
• maintaining substantially constant contact pressure between the plurality of current collectors and the plurality of armature assemblies in the presence of the magnetic field.

A method of operating a homopolar machine, comprising the steps of:

• energizing superconducting field coils in the homopolar machine to create a magnetic field through a plurality of armature assemblies, each of the plurality of armature assemblies including a plurality of armature conductor turns;
• supplying current to a plurality of current collectors that provide a sliding electrical current interface with the plurality of armature conductor turns;
• and
• maintaining an orientation of the plurality of current collectors and the magnetic field so that magnetic field lines are directed substantially parallel to a direction of current flow in a region where at least one of the plurality of current collectors contact the armature conductor turns to reduce induced magnetic forces on the plurality of current collectors.

An apparatus that includes a homopolar machine, the homopolar machine comprising:

• a shaft:
• an armature assembly coupled to the shaft;
• and
• a plurality of superconducting coils configured to produce a magnetic field asymmetry for generating an axial force on the shaft to compensate for an external axial force imposed on the shaft.

A method of operating a homopolar machine comprising:

• rotating an armature assembly coupled to a shaft wherein the shaft rotates with the armature assembly;
• energizing a first field coil in the homopolar machine to a first excitation level to generate a first magnetic field through the armature assembly coupled to the shaft;
• and
• energizing a second field coil in the homopolar machine to a second excitation level to generate a second magnetic field through the armature assembly wherein the second excitation level is different than the first excitation level for producing a magnetic field asymmetry that generates an axial force on the shaft to compensate an external axial force imposed on the shaft.