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Machine Vibration Analysis

Vibrations in machines can cause equipment failure, down-time in production, and poor manufacturing of materials.  These failures cost industry billions of dollars every year. Discovering causes and sources of these vibrations can save money and lead to increased productivity. 

Key Settings:
Mode   Recorder/Post-Processing
Views   3-D surface, Spectrum
Sampling rate  11050 Hz
FFT size   depends on test length (15 min. test use 32k)
FFT overlap percentage As detailed below.
Decimation   15 for low frequency vibration < 60 Hz
Smoothing window  Hanning
Averaging size  20
Amplitude Scaling  Logarithmic
Frequency Scaling  Linear
Sampling Precision  16 bit mono
Input   Accelerometer

Test Procedure:
  • Start the Recording
  • Slowly ramp-up machinery to full speed. Then let machines run for a few minutes at full speed and ramp-down until stopped.
  • Stop the Recording
  • Change to the Post-Processing mode.
  • Initially set the Overlap Percentage to 50%.
  • Click the rewind button to position the current file position to the start of the file.
  • Run the analyzer until the 3-D display is filled or the end of file position is reached.
  • You should easily see the ramp-up and ramp-down. Look for resonances and beat frequencies these are often the cuase of damage.
  • Use the left mouse button to readout the time corresponding to the start of the resonances or beats.
  • If the machine produces a product, inspect the product that corresponds to the times of the resonances and beats for defects.

    The same procedure applies when using the spectrogram in place of the 3-D surface plot.