GB1146912A - Electrical machine with liquid cooling of a stack of laminations - Google Patents

Abstract

1,146,912. Jointing. LICENTIA PATENTVERWALTUNGS-G.m.b.H. 25 March, 1966 [26 March, 1965], No. 13249/66. Heading B3V. [Also in Division H2] In an electrical machine having a liquid cooled laminated part 10, e.g. the stator core of a turbo generator, the laminations are secured together by tension rods 12 contained within bores 11 formed in the part 10, which are lined with an insulating layer 13 such as a plastics material and between at least one of the tension rods 12 and its insulating layer 13 there is at least one passage 17 for the flow of the cooling liquid. The core is constructed by assembling a metal tube 14, 0-ring seals 30 and bellows seal 31 around the ends of each tension rod and applying a layer of insulation to the walls of the bores 11 and/or the metal tube 14. Each metal tube 14 and tension rod are then positioned within each bore 11 and plastics material is poured, forced or injected into the gap remaining between each tube 14 and bore 11, this gap being preferably evacuated before the plastics is applied. As shown the laminations are clamped between end plates 19 arranged in a star formation (Fig. 6, not shown), the radially inner parts of which may be forked so as to pass between two winding slots. The end plates 19 are compressed by plate springs 34 and nuts 32 secured to each end of the tension rods, each being surrounded by a magnetic shield 37. The tension rods may have spiral cooling passages instead of the axial passages 17 shown or the tension rods may be spaced from the insulating layer 13 to form annular cooling passages. Radial cooling passages (38, Fig. 3, not shown), may be formed by metal rings (39), welded or riveted between the laminations for the removal of cooling gas, which may be forced into the gap between the rotor and stator by fans mounted on the ends of the rotor. Cooling liquid flows through the stator conductors (46, 47, Fig. 5, not shown), in the same direction as through the passages 17. In an alternative assembly of the core (Figs. 7 and 8, not shown), the tension rod is surrounded by a flexible tube (62) of polytetrafluorethylene which is inserted into and pressed against the wall of the bore 11 in the presence of heat. The end of the tube (62) is bent to form a sealing flange (71).