GB1391957A - Air-cooled rotary alternating current machine - Google Patents

Abstract

1391957 A.C. machines ALLMANNA SVENSKA ELEKTRISKA AB 13 July 1972 [14 July 1971] 32791/72 Heading H2A In an air-cooled rotary A.C. machine, e.g. an asychronous motor, comprising a rotor having a cooling channel 5 and a shaft 6 mounted in bearings 7 and surrounded by a laminated stator core 3 in turn surrounded by a sheetmetal casing 10 corrugated to constitute a plurality of axially directed hollow cooling ribs 15 and a plurality of integral intermediate sheet-metal parts 16 of which the latter are in heat-conducting contact with the outer surface of the stator core whilst the inner surfaces of the former define individual axially disposed cooling channels 17 which communicate with the rotor cooling channel 5, feet 11 for attachment of the machine to a machine base are mechanically connected to the stator core 3 by the intermediary of the cooling ribs 15, and the casing is fastened by each of the intermediate parts 16 to the stator core by a plurality of fastening points each being a small zone in which the core and casing materials are melted together such points together providing sufficient mechanical connections to transfer the full machine torque between the core and the casing. The melting is by arc-welding with protective gas. In the enclosed motor shown, an internal fan 12 circulates a coolant, e.g. hydrogen, or air through the broken arrow circuit the coolant passing between the ribs 15 whose ends 21 are axially sealed by circumferentially pressing together and are radially inwardly sealed by plastics cylinders 18 leaving inlet and outlet openings 19, 20; an external fan 13 having a guide cover 14 impels the unbroken arrow flow externally over the ribs. In another embodiment Fig. 3, not shown, the interior and exterior air flows intermingle and the stator core has radial cooling channels. The Specification discloses various shapes and proportions of the cooling ribs.