Integrated motor and fluid pump

An electric pump powered by an electric motor having a stator disposed within a hollow rotor is provided. Impellers on the rotor outer surface extend into a fluid flow path defined by the pump. One or more torque-producing rotor sections are driven by a plurality of independently controllable stator sections disposed within the rotor cavity. The relative positions of the rotor and stator are maintained by a plurality of bearings configured to allow rotation of the rotor and defining a bearing span. The pump is configured such that the stator and rotor share the same bearing span. Such an arrangement reduces motor windage losses relative to conventional motors in which the rotor is disposed within the stator, owing to a reduction in the diameter of the air gap between the stator and the rotor. In addition, the peripheral speed of the pump is increased owing to an increase in the rotor diameter.