A Study on Damper Bar and Integrated Rotor Slit of a Field Winding Synchronous Machine

This study focuses on the loss reduction and as a consequence efficiency improvement of a synchronous machine by designing a damper bar. The damper bar position is one of the important design parameters to reduce the electromagnetic loss of the salient pole synchronous machine. The total loss of a synchronous machine with a properly designed damper bar and integrated rotor slit can be even lower than the machine without any damper bar or slit. A parametric study has been conducted to study the influence of the damper bar position and dimension of the damper bar integrated rotor slit by rotor bar slot opening height and width. The generator has been modeled and simulated with a re-designed damper bar and integrated rotor slits, without any damper bars or slits, as well as with slits but without any damper bar, thereafter a quantitative comparison has been conducted. The study has been carried out using 2D finite element method on a Multi-MW range field winding synchronous generator. To investigate the accuracy of the simulation results, the influence of the finite element discretization (FED) has been studied by varying the number of nodes and elements.