GB938180A - Improvements in and relating to the cooling of dynamo-electric machines - Google Patents

Abstract

938,180. Cooling dynamo-electric machines; securing coils for dynamo-electric machines. C. A. PARSONS & CO. Ltd. May 10, 1961 [May 10, 1960], No. 16439/60. Class 35. In a dynamo electric machine having its rotor liquid cooled, further cooling is provided by a series of columns of cooling fluid, each column having a portion of its length in a conductor slot to receive heat generated in the conductors and another portion of its length cooled by the liquid circulating through the rotor, the columns being positioned to make use of centrifugal forces acting on portions of fluid in the column of different density to produce circulation within the column. As shown in Fig. 1 a turbo-generator rotor 1 cooled by water or oil circulating through passages 2 formed in the rotor teeth between conductor slots 3, is provided with a series of columns 7 containing a cooling fluid for effecting the transfer of heat from conductors 6 embedded in the rotor slot 3 to the rotor 1. Circulation of the cooling fluid in the two limbs 7a, 7b of each column is caused by centrifugal forces and is in a direction indicated by the arrows. The cooling fluid may be liquid or a gas such as hydrogen, helium or air, and the system may be closed or open. In the embodiment of Fig. 2 (not shown) and Fig. 3 each column is constituted by a passage 7a in the conductors, a radial passage 7b formed in the rotor face forming a side of the slot 3 and passages 7c, 7d interconnecting 7a and 7b and passing on the underside of slot wedge 9 and the underside of a supporting pad 10 respectively. In the embodiment illustrated in Figs. 4, 5 (not shown) a spacing member having radially extending passages formed therein, constituting the limbs of the cooling columns, is interposed between the faces of the rotor forming the sides of the slot and the insulation of the conductors in the slot. The cooling columns, Fig. 6 (not shown), and Fig. 7 may open into the rotor surface and by suitably shaping the inlet and outlet openings of the column to and from the rotor face, impact heads and suction heads can be produced. In a further embodiment, Fig. 8 (not shown), and Fig. 9, a passage 2 through which cooling fluid circulates to cool the rotor is located underneath the slot 3 and has a radial extension 2a which extends into the slot between two stacks of conductors 6a, 6b. The columns 7 for the cooling fluid are formed by partitions 13 which extend in the axial direction in zig-zag fashion. Passage 7a of a column is formed by a space 14 formed between partition 13 and the conductor stacks, whilst a passage 7b is formed by a space 15 between the partition and extension 2a. Connecting passages 7c, 7d are formed by slots 13a, 13b. The surfaces over which the cooling fluid flows may be finned or machined to increase the surface area. Specification 16986/1914 is referred to.