An improved ventilation system has been developed for the rotors of large conductor-cooled turbine generators which employ the gap-pickup principle. Retaining the operational advantages of the original gap-pickup design,1 low ventilation power, very uniform temperature distribution, and a simple generator assembly, the new construction requires less excitation power, has higher capability, and is mechanically simpler. Tests and operating experience indicate that the operating reliability will match the excellent record compiled by the original gap-pickup design.