A new emergency lubricating-oil system for steam turbine generators: Final report

A positive-displacement pump, powered by a turbine-shaft driven permanent magnet generator (PMG) can be used to provide lubricating oil over nearly the entire turbine generator speed range. The concept offers high reliability through its simplicity; switchgear, batteries and other auxiliaries are eliminated by hard-wiring the PMG to the pump induction drive motor. In this study, an existing PMG supplying power to the electrohydraulic control (EHC) system was evaluated as the power supply for an induction motor-driven screw pump running in a ''wafting'' mode as a backup to a conventional dc emergency oil system. The screw pump rotates all the time that the turbine shaft turns; check valves allow it to deliver oil instantly if the system pressure falls. It was found that the pump drive motor would start and run reliably with no adverse effects on the PMG or the electrohydraulic control (EHC) system. 6 refs., 23 figs., 11 tabs.