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Vibration Analysis

Vibration Analysis. Predictive Technologies PdM Techniques. Richard Henry. Vibration and Alignment Specialist VibrAlign, Inc. Cardan Shaft Misalignment Identification. Cardan shafts (shafts with universal joints) are often neglected. Cardan Shaft Alignment.

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Vibration Analysis

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  1. Vibration Analysis Predictive Technologies PdM Techniques

  2. Richard Henry Vibration and Alignment Specialist VibrAlign, Inc.

  3. Cardan Shaft Misalignment Identification Cardan shafts (shafts with universal joints) are often neglected.

  4. Cardan Shaft Alignment

  5. Cardan Shaft Alignment Technical principle Relative angular velocity

  6. Cardan Shaft AlignmentTechnical principle Degree of irregularity

  7. Cardan Shaft AlignmentTechnical principle Homokinetic operation is reached by a second cardan joint

  8. Cardan Shaft AlignmentTechnical principle

  9. Benefits of cardan shaft alignmentVibrations High wrap angle Vibrations is transfered to gear box and motor

  10. Benefits of cardan shaft alignmentWhy is it important? • Vital part in drives for process machines, breakage of cardan shafts causes down time. • Badly aligned cardan shafts set limitation in production capacity and product quality. • Stands for a considerable cost when repair is needed or a breakdown occurs. • Badly aligned cardan shafts reduces lifetime in gearboxes and motors. • Break down of a cardan shaft in running condition could be extremly dangerous.

  11. Cardan Shaft MisalignmentTypical vibration symptoms • Unbalance of the drive line (high 1X). Drive line will not have the same center of rotation as the U-Joints. • High amplitude 2X and 4X driveline speed. • Torsional oscilliation

  12. Cardan shaft alignmentMeasurement principle Angular error

  13. Cardan shaft alignmentTolerances No standard, but… • Angular error within  0.25 mils/in • Offset within specifications.

  14. Cardan shaft alignmentProcedure - Coning Coning -axis of rotation

  15. Cardan shaft alignmentCase story Background: A customer contracted VibrAlign to identify the source of an on-going U-Joint and Gearbox DE Bearing failure problem. Reasons for the in depth analysis were:

  16. Cardan shaft alignmentCase story • High vibration level. • Axial bearing had to be changed every 8-10 week. Cost about $1500 every time. • Reduced production for about 10 hours at a cost about $1000/hour for each failure. • Necessary to have bearings in stock. • Problem with thermal expansion (high bearing temps). • No method to perform the alignment.

  17. Cardan shaft alignmentCase story Vibralign arrived on site and collected initial vibration data. Vibration symptoms indicated severe cardan shaft misalignment. Using a set of brackets specially designed to measure cardan shaft misalignment, we were able to identify an angular error of approximately 1.5 mils/inch of angularity in both the horizontal and vertical planes.

  18. Cardan shaft alignmentCase story Vertical angular adjustments were made to the motor by shimming and the motor was repositioned horizontally. The following spectra and waveforms clearly show an improvement to the operation of this machine.

  19. Gearbox DE Vertical

  20. Gearbox DE Vertical

  21. Gearbox DE Horizontal

  22. Gearbox DE Horizontal

  23. Gearbox DE Axial

  24. Gearbox DE Axial

  25. Cardan shaft alignmentCase story Results: • Significant decreasing vibration level. • The alignment was performed in February -98 and no change of bearing in the gearbox has been done since then. • Increased production capacity.

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