Abstract
Vibration monitoring is an important part of predictive maintenance to assess the mechanical condition and reliability of rotating machinery in power plants. This study aims to evaluate vibration characteristics, identify potential causes of excessive vibration and give recomendation how to reduce the excessive vibration in the HP/IP Feedwater Pump at a Combined-Cycle Power Plant. Vibration measurements were conducted using a VIBXpert vibration analyzer at the Drive End (DE) and Non-Drive End (NDE) in horizontal, vertical, and axial directions while the pump operated at 2,970 rpm. Measured vibration velocities were evaluated against ISO 10816-3 standards, while Fast Fourier Transform (FFT) spectrum analysis and phase analysis were performed to identify dominant vibration characteristics. Motion Amplification techniques were subsequently used to visualize and validate abnormal mechanical movement. The results indicate that the NDE side exhibited the highest vibration levels, reaching 5.56 mm/s in the horizontal direction. FFT analysis shows a dominant component of 1× running-speed accompanied by several harmonics, while phase analysis shows a phase difference of 201° with a coherence value of 0.93. Motion Amplification revealed relative movement between the pump and its support structure, indicating potential structural looseness. Corrective actions—including tightening foundation bolts, repairing or replacing isolators, and re-leveling pump mounts are recommended to restore structural integrity and improve equipment reliability.