Integral motor pump or turbine with sensorless monitoring of axial bearing wear

A pump system or turbine system, comprising:

• an integral motor pump module (IMP) or motor turbine module (IMT) comprising:
• a module housing configured to enable a fluid to pass from an input thereof to an output thereof;
• a stator housing contained within and fixed to the module housing;
• a shaft extending axially and proximally from the stator housing;
• an impeller;
• a bearing fixed to the impeller and configured to enable the impeller to rotate about the shaft;
• a plurality of induction coils or permanent magnets fixed to a distal face of the impeller and configured to pass in proximity to a proximal face of the stator housing when the impeller rotates about the shaft;
• a plurality of stator coils contained within the stator housing and configured to be proximate the induction coils or permanent magnets as they pass in proximity to the proximal face of the stator housing, the induction coils or permanent magnets and stator coils being axially separated by a rotor-stator gap as the induction coils or permanent magnets pass in proximity to the proximal face of the stator housing, and thereby in proximity to the stator coils;
• a magnetic thrust limiter fixed to the stator housing and configured to resist a distally axial magnetic thrust of the impeller induction coils or permanent magnets toward the stator coils by applying an opposing mechanical force to the bearing, the magnetic thrust limiter thereby maintaining and defining the rotor-stator gap when the magnetic thrust is greater than a hydraulic thrust of the impeller;
• a power source or power load electrically cooperative with the stator coils;
• and
• a controller configured to:
• determine a magnitude of a back EMF generated by the passage of the induction coils or permanent magnets in proximity to the stator coils;
• determine a rotation rate of the impeller;
• estimate a magnitude of the rotor-stator gap according to a specified relationship between the rotor-stator gap, the rotation rate of the impeller, and the magnitude of the back EMF;
• and
• estimate a wear status of the magnetic thrust limiter according to the estimated magnitude of the rotor-stator gap when the magnetic thrust is greater than the hydraulic thrust.