Machines Talk. We Listen.

The routine data collection or one off vibration survey, enables VTS Consultancy UK Ltd to carry out vibration analysis on machinery that have exceeded a pre-set alarm limit, which are set in accordance with International Standards, in particular ISO 10816.  In addition, historical data records on comparable machinery are reviewed to determine what vibration levels are considered satisfactory, unsatisfactory and unacceptable.

 

Alarm limits are assigned to each individual machine, using velocity and acceleration.  These limits depend upon the size and speed of the machine and whether mounted on a rigid or flexible foundation, as well as a number of further considerations such as operational and process parameters. 

Velocity is measured in mm/s and acceleration is measured in g; where 1g = 9.81 m/s2.

 

Velocity vibration (mm/s) is generally measured using a frequency range 0-400 Hz, allowing for spectral analysis of the lower frequency faults that are common on rotating machinery, such as:

  • Unbalance

  • Misalignment

  • Looseness (foundations, bedplate, excessive shaft clearances)

  • Resonance

  • Multiple harmonics (fan blades, impeller vanes, coupling bolts, motor poles)

 

Acceleration vibration (g) is generally measured using a frequency range 0-5000 Hz, allowing for spectral analysis of the higher frequency faults, also common to rotating machinery, such as:

 

  • Rolling element bearings (inner and outer raceways, rolling elements, cages)

  • Gears

  • Turbine blades

  • Harmonics of high speed machinery

  • Cavitation

  • Electrical