Multiple system of cooling large turbo generators and an experimental study of ventilation of turbo-alternators

S. L. Henderson: The papers of Mr. Fechheimer and Mr. Bratt are of primary interest to the designer; particularly to those designers of large machines which require more than the usual air gap entrance for the admission of cooling air. To others, the papers will indicate the amount of research work which is being carried on to enable the manufacturer to build larger and better machines. To the designer the methods for calculating the air circuits may appear complicated and not easy of application. However, when the importance of the proper ventilation system is considered, the designer may well spend considerable time in laying out this part of his design. When it is realized that the construction cannot be changed once the machine is built and that the design of the machine must stand or fall on the ventilation system as laid out, too much time and care cannot be spent in its layout. In the application of the methods put forth in these papers, as in all designs, a first approximation must be made of the relative widths of the different intake and outlet belts and the pressure drops required in the different paths. When once this is done, the designer can readily see how the proportions need to be changed so that the pressures in the various paths will balance up and also so that the proper velocity distributions may be obtained.