DEVELOPMENTS IN ALTERNATING CURRENT INDUCATION MOTORS

摘要

1465268 Centrifugal pumps SEALED MOTOR CONSTRUCTION CO Ltd 8 May 1974 [14 May 1973] 22909/73 Heading F1C [Also in Division H2] An A.C. induction motor comprises a wound energized flat-face stator 32, a non-energized flatface annular magnetically permeable stator yoke body 44, and a rotor 34 comprising a thin web 40 of highly conductive material in the air-gap between the body 44 and the stator 32, the rotor 34 both having thicker hub and peripheral portions 38, 36 projecting axially to define an annular channel in which the body 44 is received, and also carrying a small amount of magnetic material arranged to produce a magnetic force towards the stator 32 which relieves axial force on the rotor away from the stator 32. In the centrifugal liquid-circulating pump shown, the magnetic material on the rotor is in the form of a layer 42 on the web 40, and is of such thickness that the magnetic attraction on the layer 42 towards the stator 32 just balances the repulsion on the web 40 away from the stator 32, and also the hydrostatic force on the impeller 10 away from the stator 32, under normal operating conditions. The impeller 10 comprises two faces 11, 13 and a plurality of sandwiched vanes 15, the face 11 having an intake aperture bounded by an axial sleeve 17.