Some problems of the turbo-alternator

Abstract

The paper is divided into sections as follow:-1. General2. Materials(a)Stator.(b)Rotor.3. Tests for flows.— The following methods are dealt with:-(a)Clink detection.(b)Optical tests.(c)Chemical tests.(d)Overspeed tests.(e)X-rays.(f)A successful potential-drop tests development by the G.E.C. Development Department. The results are published for the first time.4. Mechanical design.—This is considered from the point of view of the variation of the strength of the forging with radial depth and the efficiency of ventillation. Wedges and end-bell stresses, factor of safety, methods of test, and the available materials are dealt with. In the case of the rotor the best methods of determining the strength of the steel at the tooth root are fully discussed and methods of improving the strength of rotor forgings generally are suggested.5. Ventilation and liquid cooling.—Comparison is made between:-(a) Liquid and air cooling.(b) Wet and dry air filters and closed air systems.(c) High-speed and low-speed separately driven fans.Results of experiments on the effect of core spacers and wedges on volume and pressure of air are given.6. Insulation and temperature distribution.(a) Measurement of temperature by thermo-couples.(b) Recommended methods of insulating.(c) Maximum temperatures.7. Balancing.—A method is suggested whereby it is possible to move the balance weight at full speed. This may be worth while developing.