A special instrumented pad was installed at hydrodynamic
thrust bearing of 125 MW pump turbine in one
of Polish power plants. “Spring mattress” type thrust
bearings of these machines are quite heavily loaded
and have caused many problems so far. It was intended to
assess bearing present state more thoroughly
than with the use of standard monitoring system and to assist in bearing research and development
attempts. Instrumentation of the pad comprises 16 thermocouples for measurements of temperature
distribution in the pad and 3 proximity probes to evaluate the pad position and film thickness. The pump-turbine with an instrumented bearing was tested at various operating conditions including steady state and
transient conditions. One of the examples of the research carried out with the use of the described
instrumentation was the research into the influence of hydrostatic jacking pump operation period on
bearing performance in transient states which is presented in the paper. The results showed that current
practice of pump operation is far from optimum, and that
bearing reliability could be improved by
changing the current start-up and coasting procedures.
The results also showed that pad position during
operation is not satisfactory and also some improvement
could probably be achieved by rearranging the
support of the bearing pad.