Abstract: A liquid cooling method for a hydroelectric generator which cools the winding of the rotor via a primary cooling liquid circuit, the cooling liquid being maintained in the circuit by the produced centrifugal force. The dissipation of the thermal energy takes place via a secondary cooling liquid which flows once vertically through the system. Accordingly, the thermal exchange takes place via a co-rotating heat exchanger in the center of the rotor. A device for carrying out such a method is also disclosed.

Abstract: The invention relates to a liquid cooling method for a hydroelectric generator which cools the winding of the rotor via a primary cooling liquid circuit, said cooling liquid being maintained in the circuit by the produced centrifugal force. The dissipation of the thermal energy takes place via a secondary cooling liquid which flows once vertically through the system. According to the invention, said thermal exchange takes place via a co-rotating heat exchanger in the center of the rotor. The invention also relates to a device for carrying out such a method.

Abstract: A cooling system for bushings of an electric generator, which includes a casing housing a stator and a rotor connected to a rotor shaft activating at least a fan defining at least a high pressure zone and a low pressure zone. The generator has a plurality of phases electrically connected to hollow phase rings that are electrically connected to bushings supported by the casing and having cooling circuits to let a cooling medium pass through them to cool them. The outlets of the bushing cooling circuits are housed in the high pressure zone and are connected to inlets of the hollow phase rings. A method for cooling the bushings of an electric generator is also provided.

Abstract: A method for manufacturing a rotor by welding a plurality of elements together is described. The elements have a body with cavities and surfaces to be welded to surfaces of adjacent elements. According to the method, the elements are vertically stacked one above the other to form a pile with facing surfaces to be welded together defining slots. The cavities of adjacent elements define bores that extend within the pile. Then, adjacent elements are welded together within the slots. The bore is purged with an inert gas or mixture during welding. The slots are welded at an upper part of the bore before the slots at a lower part of the bore, and a slot at the upper part of the bore is welded last.

Abstract: A cooling system for bushings of an electric generator, which includes a casing housing a stator and a rotor connected to a rotor shaft activating at least a fan defining at least a high pressure zone and a low pressure zone. The generator has a plurality of phases electrically connected to hollow phase rings that are electrically connected to bushings supported by the casing and having cooling circuits to let a cooling medium pass through them to cool them. The outlets of the bushing cooling circuits are housed in the high pressure zone and are connected to inlets of the hollow phase rings. A method for cooling the bushings of an electric generator is also provided.

Abstract: A method for manufacturing a rotor by welding a plurality of elements together is described. The elements have a body with cavities and surfaces to be welded to surfaces of adjacent elements. According to the method, the elements are vertically stacked one above the other to form a pile with facing surfaces to be welded together defining slots. The cavities of adjacent elements define bores that extend within the pile. Then, adjacent elements are welded together within the slots. The bore is purged with an inert gas or mixture during welding. The slots are welded at an upper part of the bore before the slots at a lower part of the bore, and a slot at the upper part of the bore is welded last.