Large Synchronous Machines

The inclusion of electromagnetic and mechanical forces is a very important topic in design and construction of synchronous generators.Therefore,the mechanical stress distributions at the slot wedge and the slot bottom of a large turbo generator are analysed for various operational states.Characteristic stress peaks inside the material structure obtained from the analytical Calculation are compared with values obtained from numerically solutions.All investigations are carried out for several mechanical material properties typically used in industry.The ever increasing burden of economy narrows the possibilities of design engineers with respect to damper winding construction in turbo generators.Therefore criterions of its dimensioning are not only a functional design,but also cheapness.In order to meet these design conditions we need detailed knowledge of the current in each damper bar during all operating states of a turbo generator.Usually this knowledge is gained from fundamental flux wave linkage and some correction accounting for the deficiencies of the magnetic circuit as well as the windings.To get deeper insight the damper currents are measured.Two methods are applied.First the measuring signal is the voltage drop of the ohmic resistance of the damper bar and on second the damper current is exciting a specially built transformer and the secondary voltage used for measuring.The paper gives an overview of the used measuring sensors,the transmission and signal proc.system.