Liquid-cooled electric machine, particularly turbo-generator

Claim 1

A liquid-cooled electric machine having a three-phase stator winding in simple Y connection, such as a turbo-generator, with a stator having a multi-phase double-layer lap winding composed of winding portions, main current feed-throughs, six of said feedthroughs being associated in pairs with each one of said stator winding circuits, and circuit connectors which form electric circuit group connections between said winding portions and which connect said winding portions with said feed-throughs, said stator comprising a liquid-coolant system having two hydraulically parallel connected branch groups of coolant ducts of which a first one extends through said multi-phase winding, the second branch group extending through said feed-throughs and said connectors, insulating hose members forming part of said second branch group and fluidically bridging each two of said connectors that have different instantaneous electrical potentials respectively, a plurality of hydraulically parallel cooling branches of said second group being formed by said hose members of those of said connectors that are electrically located between each two of said feed-throughs, said connectors forming a ring conductor arrangement, each of said cooling branches between two respective ones of said feed-throughs having a portion extending through the geodetically topmost region of said arrangement, at least one insulating coolant discharge line connected to said topmost portion, a coolant collector tank with a gas cushion space mounted geodetically above said topmost ring conductor portion, said coolant discharge line forming a riser communicating from below with said tank so that said riser conducts into said tank not only coolant but, due to buoyancy, also entrained undissolved gas, said circuit connectors comprising external terminal connectors which establish the electrical connection between said feedthroughs and an end of the winding circuit, and internal circuit-group connectors which electrically series connect respective parts of said windings, said second cooling branch group forming six hydraulically parallel flow paths through the cooling ducts of the connectors, each individual one of said six paths extending through the series-connected cooling ducts of a feed-through, a circuit connector, an insulating hose section fluidically bridging the phase jump to the group circuit connector of another circuit of the winding, and thence through part of said topmost portion of said ring conductor to the cooling discharge line.