SUBMERSIBLE ELECTRIC MOTOR FOR WELL Russian patent published in 2006 - IPC F04D13/10 H02K9/19 

FIELD: oil industry.

SUBSTANCE: electric motor comprises housing, stator with winding, and rotor provided with permanent magnets and mounted on the shaft by means of sliding bearings. The cylindrical shell define a pressure-tight space together with the housing. The space receives the axial magnetic bearing. The rotor is multi-polar and made of ferrite magnets. The area of the cross-section of the tangential magnets decreases toward the axis of the rotor. The radial magnets have the constant cross-section. The shaft of the rotor is hollow. The labyrinth pumps with screws are mounted on both sides of the rotor. The inlet of the first pumps is connected with the space of the rotor shaft, and the outlet of the first pump is in communication with the space between the rotor and shell. The inlet of the second pump is in communication with the space between the rotor and shell, and the outlet of the second pump is connected with the space of the rotor to define a cooling circuit.

EFFECT: enhanced efficiency.