The Application of Hydrogen Cooling to Turbine Generators

Hydrogen has many advantages over air when used as a cooling medium for rotating machines such as reduction of windage losses, increase in available output for a given amount of active materials and the absence of corona effects on the insulation in high-voltage machines. The paper describes a liquid sealing gland developed for use with turbine generators to prevent escape of gas along the shafts. Two 7,500-kv-a., 3,600-rev. per min. generators with hydrogen cooling have been built and tested. The second machine with the control apparatus is described in detail, and the operating performance over a period of 3½ months is given. With the development of suitable sealing glands and control apparatus to the point where reliable operation can be expected over long periods, the use of hydrogen cooling for turbine generators appears to be desirable at the present time in ratings of 30,000 kw. and up.