Coupling Fault
Coupling Fault Detected in Jacket Cooling Pump
Inspection description: Vibration analysis inspection of Jacket Cooling Pump
Frequency of inspection: Monthly
Equipment description: Motor – Coupling – Pump running 24/7
Vibration reading (Velocity Power Spectrum o/all value 2.084mm/s) from the Motor Drive test point recorded in March 2012:
This spectrum indicates the vibration peaks at running speed (1X) and multiples of running speed (2X, 3X, 4X and so on). The o/all levels recorded are low however the pattern would indicate an emerging coupling fault.
Vibration reading (Velocity Power Spectrum o/all value 11.47mm/s) from the Motor Drive test point recorded in June 2012:
This spectrum indicates an increase of c. 700% in the 2X vibration component at the Motor Drive test point, indicating severe shaft – coupling misalignment.
Fault detection and action
Fault detected: Severe misalignment of motor – pump coupling. Possible damage to coupling
Recommended Action: Investigate coupling condition. Align motor - pump
Action Completed: Coupling inspected and found to be severely damaged. Coupling replaced.
Vibration reading comparison (Velocity Power Spectrum) from the Motor Drive test point recorded in July 2012 pre-replacement (middle and bottom readings) and in Nov 2012 (top reading) post-replacement.
This spectrum indicates that the previously highlighted 2X vibration component has reduced by c. 60% after the coupling was replaced. However the motor – coupling -pump was not precision laser aligned following the replacement.
Vibration reading (Velocity Power Spectrum o/all value 2.389mm/s) from the Motor Drive test point recorded in Jan 2014:
This spectrum indicates that following precision laser alignment of the motor-coupling-pump, the 2X vibration component has reduced by a further c. 50% from the original baseline.
Summary of vibration trend (Velocity Power Spectrum) from the Motor Drive test point from Oct 2010 to Jan 2014.
