Continuous Scavenging System for Hydrogen-Cooled Generators

This paper describes a new method for the operation of the hydrogen system of hydrogen-cooled generators which permits the use of untreated oil for supplying the shaft seals, thereby eliminating the need for the vacuum treating equipment formerly supplied with these generators. The new method provides for the removal of most of the air and moisture brought into the generator through the shaft seals by a system of continuous scavenging, through which the purity and relative humidity of the hydrogen in the generator are maintained at substantially the same values as are obtained with the vacuum treating system, and with a hydrogen consumption not significantly greater. Operating experience over a 4-year period with 24 generators of small and medium size, has demonstrated the reliability of the new system, and this system now is being applied quite generally to generators in all sizes except the very largest.