Hermetically sealed motor blower unit with stator inside hollow armature

A description is given of a hermetically sealed motor blower unit comprising, in combination, a sealed housing having a thrust plate and a re-entrant wall forming a central cavity, a rotor comprising an impeller, a hollow shaft, and a thrust collar, journal bearings for supporting the radial load of the shaft, and an electric motor for rotating the rotor. A motor-stator is located within the cavity and is adapted to cooperate through a portion of a re-entrant wall with a motor-rotor mounted within the hollow shaft. The portion of the re-entrant wall located between the motor-stator and the motor-rotor is made relatively thin to reduce electrical losses. A fluid pumped by an impeller lubricates the bearing surfaces