Experimental Characterization of Vibrations on Bucket Wheel Boom of Excavator on Thermal Power Plants “N. Tesla”-B

The paper presents the most important measurements related to the vertical vibrations characterization of the bucket wheel boom (BWB) of excavator in the coal delivery system at Thermal Power Plant Nikola Tesla"-B. The position of the BWB was measured, as well as the pressures above and below the piston on the hydraulic cylinders for his vertical movement. Based on this measurements, vibration analysis was performed and the dominant oscillation modes were detected with frequencies of 0.5 [Hz] (for the case of the BWB operating mode when is performed being coal grip) and 0.59 [Hz] (for the case with the BWB when rising in the air). Based on these values and the known speeds of raising and lowering the BWB, the vibration amplitudes were determined. Among other things, the analysis and determination of the period of damped oscillations of the BWB proved to be very important for determining his equivalent moment of inertia. Based on the obtained measurements and analysis of vibrations, all the lacks of the existing system were noticed and a new solution of the BWB electro-hydraulic drive was designed, which was at the end successfully realized. The results presented in this paper are part of the project "Reconstruction of the electro-hydraulic drive of the BWB on TPP Nikola Tesla -B", which was done in August 2017, system implementation, commissioning and exploitation testing the BWB electro-hydraulic drive were done in mid-December 2017, since when the complete system has been in use at the coal delivery system.