GB787519A - Improvements in devices for ensuring an electric contact between rotary parts of an electric machine - Google Patents

Abstract

787,519. Liquid collecting-devices for dynamoelectric machines. COMMISSARIAT A L'ENERGIE ATOMIQUE. March 16, 1956 [March 30, 1955], No. 8357/56. Class 35. A homopolar generator comprises a shaft 1 driven by pulley 2 and field windings 3, 4, cooperating with armatures 5, 8, which are insulated one from the other. The brushes of the machine comprise annular members 13 mounted on the shaft and fixed together by bolts 41 which apply them against sleeve 14. Fixed annular elements 16, 17 surround the members 13 so as to provide a gap 15 sufficient for the passage of mercury or other conductive liquids. Each element 16 has a groove 19 which is filled with liquid when the machine is to be started, an edge 20 projecting into groove 21 in the member 13 preventing leakage of liquid along the shaft. Liquid is fed into the gaps 15 through conduits 23 and passages 22 in the upper elements 17, and also through conduits 25 and passages 24 opening into grooves 19. The outflow of liquid from the gaps takes place through spaces 26 and conduits 27. Externally of the machine, the conduits 23, 25, 27 are connected with a heat-exchanger for cooling the liquid and with valves for adjusting the flow-rate as well as with flow meters. Current is collected from the brushes by means of bars 31, 32 connected to a squirrel cage 33. The chambers 11, 12 are gas-tight and filled with nitrogen, the windings 3, 4 being separately housed and cooled by forced draught. The liquid-conduits are emptied when the machine is not in use, means being provided for filling the liquid-circuit quickly upon starting the machine. For this purpose a tank is provided at the lower part of the machine and the liquid is drained into this tank by opening a valve and placing the tank under atmospheric pressure, Fig. 2 (not shown). To fill the liquid-circuit, nitrogen under pressure is supplied to the tank so that the liquid rises into conduits 23, 25 and tends to fill gap 19. If the machine is then started, the liquid is gradually projected by centrifugal action through the conduit 27 so that the whole circuit is eventually filled with liquid and circulation takes place through the heat-exchanger with the circuit cut off from the tank.