Overflow ducts of a generator with direct induced-draft cooling

摘要

In a generator which is operated according to the induced- draft- cooling principle and in which a main fan (11), attached to the rotor shaft (12) of the generator, draws cooling medium, which is heated by the heat-generating elements of the generator, out of the generator and transports it essentially perpendicularly to the axis of this rotor shaft (12) to a cooling arrangement (23), the drawn-in cooling medium, which is expelled with a swirl at high velocity by the main fan (11), being received by a cooling-duct casing (33), which directs the cooling medium to the cooling arrangement (23) via at least one fluidic constriction (41) , the directing of the cooling medium, while efficiently avoiding vortices and pressure drops, is achieved in that the cooling-duct casing (33) has at least one overflow duct (66), which receives the cooling medium, expelled into the cooling-duct casing (33) by the main fan (11), via an inflow zone (58) upstream of the constriction (41), diverts the cooling medium around the constriction (41) and directs it to an outflow zone (59) lying downstream of the constriction (41) in the direction of flow, where the cooling medium flows into the cooling-duct casing (33) again.