GB800613A - Improvements in or relating to stator cores for dynamo electric machines - Google Patents

Abstract

800,613. Dynamo-electric machine core constructions, casings and cooling. WESTING- HOUSE ELECTRIC INTERNATIONAL CO. June 20, 1956 [June 29, 1955], No. 19036/56. Class 35. A dynamo-electric machine stator core 7, e.g. for a turbine-driven generator and having a plurality of teeth spaced about the inner surface of an annulus, comprises at least one annular assembly 60 which, or each of which, comprises a plurality of layers of orientated magnetic sheet laminations including segmental core laminations 41 having an arcuate span which embraces a plurality of the teeth and a grain orientation approximately in the circumferential direction of the core, and short tooth laminations 42 and long tooth laminations 43 having radial lengths respectively equal to those of the teeth and of the radial depth of the assembly and both having a grain orientation approximately in the radial direction of the core and being so located as to provide the plurality of teeth, with circumferentially spaced winding receiving slots 11 therebetween. Layers of the long tooth laminations 43 are provided at and between the ends of each laminar assembly 60 to assist in holding the laminations 41, 42 together. Adjacent layers of segmental laminations 41 have their radal butt joints 44 staggered. and each laminar layer has a circumferential extent of either 360 degrees, or slightly more or less than 360 degrees so that successive layers overlap each other. In a modification, not shown, long tooth laminations 43 may be interposed in layers of segmental and short tooth laminations 41, 42. The laminations have ventilating holes 40, clamping bolt holes 38, building bolt notches 37, and notches 14 to receive wedges 15 for retaining the coil sides of a, e.g. H.V. polyphase, winding 12, directly cooled by ventilating ducts 13. Preferably instead of the usual insulating coating the laminations have applied thereto during assembly a fluid non-electrically conducting bonding material which subsequently is hardened under heat and pressure to bond the layers together into an integral assembly 60 of which there may be many, as shown in Fig. 6. The assemblies 60 are keyed on to building bolts 16 carried by axially-spaced inner frame rings 21...24 resiliently spaced by springs, not shown, from an outer frame comprising axially-spaced rings 31...35 and a hermetically pressure-tight enclosure 29 filled with hydrogen under pressure. To decrease heating due to end leakage flux the end core assemblies 60a ... 60d have bore diameters which progressively increase towards the ends.