Upgrading gates drives in the hydroelectric power plant. The paper describes the nature of the modernization gates drives in small hydroelectric power stations. It has been pointed out the benefit of the application of hydraulic drives with digital control systems.

Using a series of Renard in the design process of hydraulic and pneumatic components. The article presents a series of Renard preferred numbers, recommended by ISO 3 to use in selecting the size for geometric elements of the design hydraulic and pneumatic systems. The manner of determination and application, as well as examples of use have been described.

Upgrading of electro-hydraulic control systems of power units. The paper presents a steam turbine control method for active power generation. The upgrade level of the system for power control has been described. The need for modernization as well as the advantages of the new solution has been pointed out.

Research of hydraulic leg with gas accumulator. The measurements of deviations of selected parameters of the hydraulic leg with gas accumulator on the test rig have been carried out. Numerical model has been developed and FEM analysis has been performed. The results of the experimental and numerical tests have been compared.

Design of cycloidal gears made of plastic which are used in gerotor pump. The article presents the analysis of stresses and displacements which occur in the cycloidal gears working in the gerotor machine. The authors considered a possibility of using plastic (polyoxymethylene POM) for manufacturing the cycloidal gears. The analysis has been conducted by means of the finite element method. Determining the maximum value of pressure which can be applied in the gerotor machine featuring plastic gears is the result of the analysis.