Design and Analysis of T-Shape Dovetail for Improvement in Peripheral Velocities

From the olden days in synchronous machines for attaching mechanically pole windings to the shaft dovetails are used. In general T-shape or Hammered head section is used as type of dovetail. Hammered head dovetail is a modification of T-section. Now a day there is a lot of demand for the Steam turbo generators. These synchronous generators require high runaway speed. High speeds can be achieved by using the forged shafts or by using high strength material for the punched spiders. Forged shafts are economically not preferable due to reason of more lead times and costly machining processes etc. Laminated spider type shafts are used in some cases. It is limited by the strength of the material, i.e. limitation in getting high strength material economically is difficult. To overcome above constraints Modification of dovetail section could be the one of possible solution to overcome above constraints for a high peripheral velocity. This is explained step by step in this report, from developing base line for the T-section dovetail model to possible modifications into new geometric models. Percent of improvement in peripheral velocities are calculated with respect to base model.