Hydrogen as a cooling medium for electrical machinery

This paper presents the results of a large amount of theoretical study and a large number of tests to determine the advantages of hydrogen as a cooling medium in electrical machiney. The conclusions fall into two classes, some definite and some speculative. In the former class are: 1. For the same operating temperature a steam turbine-driven generator of a given size will have a capacity at least 30 per cent greater when operated in hydrogen than when operated in air. 2. The efficiency will be 1 per cent or more higher. 3. There will be no danger of fire destroying the insulation. 4. The detrimental effects of corona if present will be greatly reduced. 5. The machine may be protected by suitable devices from the formation of an explosive mixture of hydrogen and air. 6. The frame can be made sufficiently strong to resist an explosion. This is additional security in case of failure of the protective devices or negligence in operation. 7. The cooler for removing the heat from the hydrogen may be considerably smaller than a cooler for removing heal from air. In the speculative class are: 1. A hydrogen pressure of several atmospheres will result in still greater possibilities provided a sufficiently gas tight enclosure can be developed. 2. The insulation may be made thinner and still have as long a life as the present insulations operated in air.