CENTRIFUGAL COMPRESSOR UNIT AND ELECTRIC MOTOR Russian patent published in 2000 - IPC

FIELD: air conditioners and refrigerators for industrial and domestic application. SUBSTANCE: compressor unit has two compression stages with impellers, diffusers, collecting chambers, inlet pipe running to first compression stage, and outlet pipe running from second compression stage. Electric motor placed between compression stages has its rotor mounted on shaft also carrying compression-stage impellers. Cooling ducts are provided on external side of stator. Collection chamber of first compression stage communicates with second-stage inlet. Motor frame interior communicates on one end with inlet pipe and on other end with coolant outlet pipe which is connected to inlet of second compression stage. Coolant flow path is formed in frame by cooling ducts provided between stator and frame and by stator-to-rotor air gap. According to invention, first-stage collecting chamber communicates with second-stage inlet directly through motor frame interior. Motor stator is built up of toroidal laminated core and circular winding. Rotor is assembled of isolated permanent magnets made in the form of thin high-resistivity rings and non-conducting banding. Radial stator-to-rotor air gap is at least 1.5 mm. EFFECT: improved reliability and operating efficiency of compressor and motor. 15 cl, 2 dwg