The article presents selected problems related to an analysis of damage to wind turbine planetary gear. It is the most vital element installed in wind turbines, affecting the operational costs (prolonged downtime), and costs of repairs and servicing including delivery of required components. The authors have analyzed the wear/failure of planetary gear. The process initiating fatigue wear, different from similar devices in other industries, can be easily observed in wind turbine gear. This establishes a specific direction of research into the causes, and early detection of ‘gas spots’ on gear teeth as they seem to trigger fatigue wear.

This article presents an original method of using elastic waves of acoustic emission (AE) to assess the technical condition of nozzles in marine diesel engines. The developed method makes it possible to detect the early stages of wear by friction of the needle-nozzle pair. The phenomenon of AE and the possibility of its use in evaluating the condition of marine diesel-engine injectors are discussed. Experiments are presented in which the AEs were used to evaluate the condition of both a new injector and an injector where galling of the needle-nozzle pair is developing. The measurements were processed by time–frequency analysis and wavelet transformation.

Although mud pumps are vital components of a drilling rig, their failures are frequent. The identification of technical condition of these high-pressure piston pumps is difficult. There are no reliable criteria for the assessment of mud pump condition. In this paper, faults of the pump valve module are identified by means of acoustic emission (AE) signals. The characteristics of these signals are extracted by wavelet packet signal processing. This method has been verified by experiments conducted on a NOV (National Oilwell Varco) -made triplex 14-P-220 mud pump (mounted in the drillship). The results show that the wavelet packet signal processing method can effectively extract the frequency band energy eigenvalues of the signals. Besides, some operational problems associated with high pressure piston mud pumps are presented. A non-invasive method for diagnosing the technical condition of such pumps is being developed at the Maritime University of Szczecin.

The article draws attention to the problems of maintaining fuel injection pumps of marine diesel engines in the conditions of the use of residual fuels in which the quality is steadily deteriorating. The analysis of tribological processes occurring in hydraulic precision pairs of fuel injection pumps, such as a barrel-plunger, is presented. Problems occurring regarding the operation of injection pumps and the possibilities of their avoidance on board are discussed. The means of condition monitoring, including the application of thermography methods, are characterized. The authors have done research concerning diagnosing injection systems of high and medium power engines by using acoustic emission (AE) signals. The experiment results obtained with the use of acoustic emission and wavelet analysis confirmed the dependency of the frequency components contained in the acoustic emission signal on the condition state of the injector pumps’ tribological pair.

The article describes research into the use of acoustic emission elastic waves (AE) for diagnosing insulated-gated bipolar transistors (IGBTs). Currently used in many modern shipboard power electronic systems, IGBTs are crucial components required to operate with extreme reliability. The acoustic emission elastic waves method was used to determine the acoustic signals of switching transistor and can be used to monitor early stages of damage. Transistor diagnostics makes use of selected frequency descriptors of AE and appropriate signal analysis.