Stator Bar’s and Winding:-
Stator bar design incorporates the use of thermosetting epoxy mica insulation conforming to class “F” The bars/coils during manufacture are provided with conductive coating wrapping tape for minimisation of corona discharge semiconductive varnish/tape is applied a uniform temp distribution in operation double-layer lap winding with half Rebel / multitier type/diamond shaped coil employed in stator winding over-hang is robustly designed to withstand stress in operation resistance Thermometers/Thermocouples are mounted in stator core stator teeth stator winding air inlet and outlet zone of the stator frame their lead are suitable brought out to a terminal board mounted on the stator frame.
In the case of air cooled Turbo generators fire detector relays are mounted over the winding over hang for alarm and automatic injection of in case any fire this arrangement is provided for generators of 5mw capacity and above and for lower rating based on customer requirement.
Brush gear is robustly designed with radial type brush holders brushes of natural graphite composition with low efficiency of friction and self-lubricating properties are used which ensure smooth and trouble-free operation. The brush type gear is either fixed on to the end of the stator and cover or bearing or is mounted separately on a pedestal depending on requirements generator’s are provided with on load brush changing gear for generator brushes the advantages of this arrangement are
– constant spring tension over the entire brush wear.
– brush change over without stopping the machine.
– safety of personnel due to a provision of an insulated handle.