Condition Monitoring of a Compressor Motor Unit: An Investigation of Abnormal High Pitch Noise

摘要

Condition monitoring of machinery through the use of vibration analysis and modal identification is a cost effective techniques involving the continuous assessment of machinery components in order to identify any changes in the system dynamics, e.g., changes in the dynamic characteristics of the system, detect early stages of component degradation and prevent catastrophic failures. However, condition monitoring by itself can only pinpoint the root causes of failures but fault interpretation such as poor design, poor assembly, wear and tear, imbalance and misalignment due to bad manufacturing processes, is mainly triggered by the user. In this paper the condition monitoring of a compressor motor is examined for continuous high pitch noise. Analyse technique used in the investigation includes machine maintenance history, trending, and sound intensity analysis to determine the noise source location and side bands around the dominating high pitch frequency components in the noise spectrum. Due to the amplitude modulating effect on the characteristic frequencies of the compressor motor, a Fast Fourier Transform (FFT) frequency spectrum of the modulating signal have been considered to record the dominant impulsive force at the dominating high pitch frequency. Strong frequency components due to a gradual increase in the vibration at specific running speed of the compressor motor rotor bars have been observed.