Electric machines, particularly turbogenerators, having liquid cooled rotors

In an electrical machine having a housing, a shaft extending through the housing, a rotor mounted on the shaft within the housing, electrical conductors disposed within the housing, electric generating means mounted on the shaft externally to and to one side of the housing, and a coolant water distribution chamber located on the shaft at the one side of the housing, a coolant water receiving chamber surrounding the rotor, means for conducting coolant water in heat transfer relationship with the electrical conductors in the housing from the coolant water distribution chamber to the coolant water receiving chamber, axially extending channel means at the surface of the shaft connecting said coolant water receiving chamber to a collecting chamber located adjacent thereto, contact-free sealing means comprising labyrinth sealing rings sealing said collecting chamber from surrounding space within said housing, means for supplying hydrogen as cooling gas to the housing, and blower means for moving a flow of said hydrogen cooling gas as a barrier gas into said labyrinth sealing rings so as to block contamination of the coolant water in said collecting chamber by ambient oxygen in said surrounding space within the housing, both said collecting chamber and said labyrinth sealing rings being disposed within the housing.