Rotating machinery in industrial applications requires accurate vibration measurement for fault diagnosis and maintenance decision-making. IEPE sensors provide high accuracy, their cost limits large-scale deployment. This study evaluates the frequency, amplitude, harmonic, and noise performance of low-cost MEMS accelerometers in comparison with a reference IEPE sensor. Three MEMS accelerometers and one IEPE sensor were mounted on a vibration shaker and excited by sinusoidal signals in the 10–100 Hz range, with data simultaneously acquired at a sampling rate of 2 kHz. FFT-based analysis was applied to assess frequency tracking accuracy, narrowband RMS amplitude, harmonic detectability, noise floor, and signal-to-noise ratio (SNR). Additional experiments examined an electric motor under unbalanced conditions to examine practical applicability. The results indicate that the MEMS sensors achieve consistent sub-bin frequency tracking, with peak deviations remaining well below the theoretical FFT resolution (Δf = 0.2 Hz) for both fundamental and harmonic components. However, the narrowband RMS amplitude shows frequency-dependent deviations of up to approximately ±50–70% relative to the IEPE reference, and the SNR of the MEMS sensors (25–35 dB) is lower than that of the IEPE (>40 dB). These findings demonstrate strong potential for frequency-based condition monitoring, while accurate amplitude evaluation requires calibration.

Keywords

MEMS accelerometer, Vibration analysis, Induction motor, FFT, Condition monitoring