GB1038011A - Improvements in or relating to fractional horse-power two-phase or multi-phase dynamo-electric machines - Google Patents

Abstract

1,038,011. Dynamo-electric machines. A. KALTENBACH and E. HOFFMEISTER. July 8, 1963 [July 9, 1962; May 30, 1963], No. 27024/63. Heading H2A. In a two- or multi-phase F.H.P. dynamoelectric machine, e.g. a dental handpiece motor or a generator, having arranged in slots in a laminated stator core 7 rod-like stator winding conductors 8, the conductors of each phase are connected together in groups at both ends by connecting parts 9 ... 11 extending about the stator axis, the conductors and the stator core radially outer surface are so synthetic plastic, e.g. cast resin embedded that only the stator base and those parts for connection to a current source are free of the embedding material 12, and the connecting parts at one end are arranged for connection to the source by resiliently mounted connecting pins 14 carried by a closure cover 3. In the motor shown, the rotor 5 is of either the squirrel-cage or permanent magnet type, and the three-phase source is fed through a cable 13, springs 15, and the pins 14, to three contact segments 11 whence the current flows through three groups of the uninsulated (L.V.) conductors 8 to respective short-circuit rings 9 and back through other conductors 8 to contact segments 10 which are short-circuited by the cover 3 to form the star point; an alternative cover 3 provides a delta connection. The slots may be closed or semi-open, and contain more than one layer of conductors 8 in which case their individual cross-sections are supplementary to fill the slot. For V.H.F. operation the core 7 may be of ferrite.