Vibration Analysis Predictive Technologies PdM Techniques.

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Transcript of Vibration Analysis Predictive Technologies PdM Techniques.

  • Vibration AnalysisPredictive TechnologiesPdM Techniques

  • Richard HenryVibration and Alignment SpecialistVibrAlign, Inc.

  • Cardan Shaft Misalignment IdentificationCardan shafts (shafts with universal joints) are often neglected.

  • Cardan Shaft Alignment

  • Cardan Shaft Alignment Technical principleRelative angular velocity

  • Cardan Shaft Alignment Technical principleDegree of irregularity

  • Cardan Shaft Alignment Technical principleHomokinetic operation is reached by a second cardan joint

  • Cardan Shaft Alignment Technical principle

  • Benefits of cardan shaft alignmentVibrationsVibrations is transfered to gear box and motorHigh wrap angle

  • Benefits of cardan shaft alignment Why 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.

  • Cardan Shaft Misalignment Typical 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

  • Cardan shaft alignment Measurement principleAngular error

  • Cardan shaft alignment Tolerances

    No standard, but

    Angular error within 0.25 mils/in Offset within specifications.

  • Cardan shaft alignment Procedure - ConingConing -axis of rotation

  • 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:

  • 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.

  • 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.

  • 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.

  • Gearbox DE Vertical

  • Gearbox DE Vertical

  • Gearbox DE Horizontal

  • Gearbox DE Horizontal

  • Gearbox DE Axial

  • Gearbox DE Axial

  • Cardan shaft alignmentCase storyResults: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.