Electrical sub-fractional motor with encapsulated rotor

Claim 1

A sub-fractional electrical induction motor adapted for use in the presence of magnetic contamination of a non-explosive nature comprising: an open magnetic stator frame of electrical steel laminations defining a main flux path for the motor and having an opening for receiving a rotor, said stator frame affording at least one pair of pole pieces distributed equally around said rotor opening; the portion of said stator frame encompassing said rotor opening being integrally molded into a plastic sealing block completely sealing all sides of the rotor opening except two axially aligned open ends; an electrical coil magnetically coupleD to said stator frame; a pair of bearing brackets, affixed to said stator frame and extending across the opposite open ends of said rotor opening, each bearing bracket being tightly sealed to said sealing block to define an enclosed rotor space; two sealing gaskets, individually interposed between said sealing block and respective ones of said bearing brackets; and a rotor, positioned wholly within said rotor space, said rotor being mounted on a shaft supported in said bearing brackets, at least one of said bearing brackets having an axial opening through which said shaft projects to afford an output for the motor.