Outdoor hydrogen-ventilated synchronous condensers

Hydrogen is an excellent cooling medium for high-speed rotating electrical machinery. When it is substituted for air, a machine can be operated at a higher load with the same temperature rise and the windage loss is decreased to one-twelfth. Furthermore, since no oxidation can take place in this type of machine, the life of the insulation is increased and short circuit and corona troubles are very materially reduced. The machine is especially quiet, and it can be placed out of doors without increased expense. The first commercial application of hydrogen cooling for electrical machinery was made on a 12,500-kv-a. outdoor synchronous condenser. Another outdoor hydrogen-cooled condenser designed along these lines rated 20,000 kv-a., is also in operation. Both condensers were placed in service in 1928 and their performance has been very satisfactory. This paper describes the construction of the machines and reviews the advantages and disadvantages of hydrogen cooling.