GB1034962A - Improvements in liquid cooled electrical machines - Google Patents

Abstract

1,034,962. Centrifugal pumps. LICENTIA PATENT-VERWALTUNGS-G.m.b.H. March 8, 1963 [March 10, 1962; June 28, 1962], No. 9358/63. Heading F1C. [Also in Division H2] An impeller directly coupled to the shaft of an alternator serves to pump cooling water through the cooling passages of both stator and rotor. As shown, the pump impeller has two radial pumping passages 1A, 1B. Water or oil is drawn from tank 3, and part of it is directed by impeller 1A via outlet 11A and pipe 12 to the stator 13 and thence back to the tank, while another part is drawn through the rotor by ducts 8 and 9 by impeller 1B and returns via outlet 11B to the tank. In a modification (Fig. 1, not shown), the pressure chambers 10A, 10B of the two impellers are joined together to make a single delivery to the stator. A single, double-way impeller (Fig. 3 and 4, not shown) may be used to feed both circuits. Passages 22 (corresponding to impeller 1B of Fig. 2) draw water from the rotor while passages 21 (corresponding to impeller 1A) deliver the main body of water to the stator, the outputs of both impellers being delivered to the stator in this case. The blade-angle for impeller 1A is modified by blade-thickening, as shown. In another modification (Fig. 5, not shown) the water is forced rather than drawn through the rotor to avoid cavitation. Impeller 1 draws water from inlet 5, forces it into a stationary guide member 33, from whence it passes to the rotor by annular passages 34, and also through a by-pass 36, to feed the stator at 37 in combination with the returning rotor water at 35. The same effect may be achieved by pressurizing the whole system by putting the tank 3 above the machine, e.g. on its casing, or by means of a head of nitrogen in tank 3. Alternatively, (Fig. 6, not shown), the pump may comprise two ports, a main pump which delivers water under pressure to both the stator and rotor circuits, the flow division being adjustable by valves, and an auxiliary pump which draws the used water from the rotor. Reference has been directed by the Comptroller to Specification 916,762.