GB1266622A - - Google Patents

Abstract

1,266,622. Brush gear for dynamo-electric machines. GENERAL ELECTRIC CO. Ltd. 4 Aug., 1970 [4 Aug., 1969], No. 38961/69. Heading H2A. In an arrangement for transferring current between the stator and rotor of an electrical machine, a brush member skates on a thin film of liquid formed on an annular surface. The liquid may be mercury, or an NaK or Gain alloy, and is retained on the annular surface by centrifugal or surface tension forces. In Fig. 1 metal brushes 2 are carried in slots 4 in the periphery 5 of the rotor 1 and are urged against an annular surface 7 centrifugally. The liquid is supplied through channels 8, 9 in the rotor and brush, and the lower brush surface 6 is chamfered from the leading to the trailing edge to ensure laminar liquid flow in the layer 10. In modifications, the rotor periphery 5 may fit inside a slot in the brush, or member 1 may be the stator and annulus 3, the rotor (Fig. 2, not shown), in which case a spring (15) urges the brush towards the surface 7. In a further modification (Fig. 6, not shown), the brush 34 comprises a bundle of flexible metal or carbon fibres fixed to the rotor. In Fig. 3 a ring of arcuate brushes 19 are each pivotally mounted (20) on an annular stator part 18, and skate over a liquid layer on an annular surface 22 of the rotor. The pivots 20 may be spring-loaded, and two such rings of brushes may be provided. In Fig. 4 brushes 26 are carried at the ends of resilient strips 25 mounted on the stator or rotor 24. Alternatively, the strips 25 may be used alone, without the brushes 26. In another version (Fig. 5, not shown) resilient fingers (31) extend in the axial direction from, and are formed integrally with, the rotor disc (30), the fingers terminating in brush portions (33) which are thrown outwards, centrifugally, towards the annular surface carrying the liquid layer.