Patent GB-285845-A (GB)
Title: Improvements in or relating to cooling arrangements for dynamo electrical machines
IPC: H02K9/19
Filed: 1927-08-22
Abstract: 285,845. Blathy, 0. T. Feb. 23, 1927, [Convention date]. Armature and field magnets, cooling and ventilating.-In a machine in which both liquid and air are employed for cooling, liquid cooling- elements are interposed between and in thermal contact with groups of the stator laminae, while air gaps for cooling the cooling air are located between the liquid-carrying elements and the stator laminae. The air ducts may, alternatively, be formed entirely within the elements. Fig. 1 shows the general arrangement in the machine, and Figs. 2, 3, 6 and 8 are details of the liquidcarrying elements. Between the groups of the stator laminae b, Fig. 1, hollow cooling-elements c are placed, these being approximately of flattened ring form and communicating with distributing and collecting conduits d, c and with the cooling-liquid inlet and outlet at f and g. The liquid, which may be condensate-water, may flow from the outlet to a cooler and thence, in closed circulation, to the inlet again. The elements c may be made of two sheet walls h, Fig. 2, welded together at their outer edge h<3> and furnished at their inner edge with extensions h<1> shaped to fit the stator teeth and welded or soldered to a correspondingly shaped U-sectioned insertion h<2>. Resistance to axial pressure is given by insertions i, arranged concentrically, as shown in Fig. 1. The position of these stiffeners may be determined by welded radial ribs j shown in Fig. 3 which is a section on the line 3, 3, Fig. 2. These ribs are in recesses k formed in one or both of the plates h and serving the dual purpose of conducting heat from the stator iron to the liquid and defining air ducts between the liquidelements and the iron through which the cooling air from the rotor passes. This air is also cooled by the liquid and mav flow back to the rotor in a closed path. The ribs k may be formed as solid projections integral with the plates h, or, as shown in Fig. 7, the plates may be deformed so as to give air ducts and plate portions in contact with the stator laminae. Fig. 6 shows a form in which superposed rectangular tubes c<1> are employed with portions projecting at intervals in contact with the stator iron, as shown, and Fig. 8 shows a form in which the air passages m are formed within the liquid-carrying ducts c in addition to the external air passages l in contact with the laminµ. The machine casing is provided with recesses p, Fig. 1, for the liquid inlet and outlet connections and the concentric passages of a single cooling element are preferably connected to the conduits d, e in such a manner that individual passages may be closed off. The inlet and outlet points may be spaced apart by a greater or smaller angle than the 180 shown in Fig. 1. In another arrangement, Fig. 9, water-cooling elements c<2> are interposed between groups of stator laminae k alternately with radial air gaps or passages l. In this case, the warm air is water-cooled both by direct heat transmission through the walls k to the water outside the air headers l<1> and by transmission through the laminae and the walls k to the water in the passages c<2> between the groups of laminae.