GB863073A - Improvements in or relating to dynamo electric machines - Google Patents

Abstract

863,073. I)ynamo-electric machines. WESTINGHOUSE ELECTRIC CORPORATION. March 14, 1958 [March 21, 1957], No. 8258/58. Class 35. In a dynamo electric machine, such as a turbine driven generator, having a stator core 5 divided into two or more groups 51, 5<SP>11</SP> of laminations 15 spaced axially apart to provide one or more radial ventilating spaces 11 and a stator winding 18 inner cooled and insulated by a fluid e.g. oil or hydrogen circulating through longitudinal channels 28 formed in the winding ground insulation 23, the fluid is conducted from the channels 28 to the spaces 11 by insulating diverter members 14 formed as a ring and fitting within toothless laminations 12 bounding the space 11 and having a bore of diameter greater than that of the radially outer parts of winding slots 16 in the laminations 15. As shown, the winding comprises substantially bare end portions 21 and slot portions 20 whose ground insulation 23 includes an outer sheathing 30 and stiff spacers 27 defining the channels 28 which are open to the light by insulated strands 22 of the winding; the strands may be transposed in the slot or end portions or both. Within the diverter, Fig. 9, openings 36, 37 in the ground insulation permit fluid flow through transverse and radial ducts 38, 39, Fig. 7, to the spaces 11, whence it is circulated by a pump P through a heat-exchanger 10 back to end bell spaces 46, 47 for re-entry into the channels. Two multi-stage axial-flow fans 55, 56 circulate a fluid e.g. hydrogen through respective coolers 57, 58, a D.C. field winding 52, radial holes 53 in a solid rotor core 50, and the air gap 54, a cylindrical electrically insulating partition 3 and flexible diaphragms 7 being provided between the rotor and stator; alternatively, the partition may be omitted and a single cooling system provided for both rotor and stator. The cooling fluid is chosen to have the same dielectric constant as the ground insulation 23, which may be graded. Specifications 722,151, 722,152 and 753,114 are referred to.