Abstract: A modular permanent-magnet electric motor assembly having a predetermined maximum power output for a submersible pump assembly, a stator having a plurality of electric coils adapted to be energized to create a magnetic field, and a rotor assembly disposed about a rotor shaft. The rotor assembly comprises a predetermined number of rotor modules sufficient to achieve the predetermined power output and a pair of bearing carriers separated by the rotor modules. Each rotor module comprises a rotor core and a plurality of magnets disposed about or otherwise associated with the rotor core. The magnetic field between the coils and the magnets causes rotation of the rotor modules, the rotor assembly, and, thus, the rotor shaft. The rotor assembly desirably also includes a protective sheath to prevent fluid from entering the rotor assembly and contacting the rotors. The predetermined number of rotor modules are installed on the shaft during the process of manufacturing the motor.

Abstract: A thrust bearing assembly for a submersible motor assembly of a submersible pump assembly comprising first and second bearing members or plates and first and second bearing holders contained within a housing. Each bearing plate is in the form of a disk having a bearing surface, and the first and second bearing plates are disposed between the first and second bearing holders with the bearing surfaces in face-to-face contact. The first bearing holder is in the form of a thrust bearing holder, and the second bearing holder is in the form of a gimbal plate. The first bearing plate is adapted to rotate with a rotor shaft of the submersible pump assembly and to impose a thrust load on the second plate, and the second bearing plate is adapted to remain stationary relative to the rotating first bearing plate. Grooves are defined by one or both of the bearing surfaces to allow fluid from a fluid supply to enter between the bearing surfaces to create a fluid film to lubricate and cool the bearing surfaces.