Onsite Diagnostics and Condition Evaluation of Rotating Machines

In this paper the focus is laid on the diagnostic methods for rotating machines with respect to condition evaluation. In an overview the diagnostic measurements were presented and discussed. The most important factors for evaluation criterions were insulation resistance, dissipation factor, partial discharge and voltage withstand test. Some of these test results deliver absolute parameters and some have to be evaluated relatively. For the condition evaluation the absolute parameters deliver the information about the compliance of threshold values (passed/failed) to guarantee save operation within the next service interval. The relative parameters are helpful to find weak points in the electric insulation system, e.g. with PD pattern
recognition the source of failures can be detected. In dependence of the maintenance strategy the results of the measurements and condition evaluation give helpful information for the decision of the further operation or if there have to be done any measures as overhaul, servicing or repair.