Key setup parameters 02 2008

Key Setup Parameters for Meaningful Vibration Data Analysis Dennis H Shreve Commtest Inc Knoxville, TN Meaningful Vibration Data Analysis • Lots of tools and techniques available • Sometimes can be a bit intimidating and burdensome • Need to take away some of the mystery • Make the best of the situation • Examine scientific terminology and industry jargon Getting Down to Basics • • • • • • Vibration is a leading indicator of machinery health Accelerometer is like a doctor’s stethoscope Capture the raw data Convert to a “signature” for comparison Know the equipment make-up Watch for patterns, amplitudes, and changes over time (Interpret information relative to PF curve) Predictive Maintenance (PdM) (an evolution from Breakdown to Preventive) • Key Elements to the process: – Detection – Analysis – Correction – Verification • Pinpoint a problem, get to the root cause, take action, and verify effectiveness DETECTION • • • • Capture details on equipment and application Choose the right sensor Set up the right measurement parameters Obtain good, solid data – also, repeatable ANALYSIS • Examine trends, changes, patterns, and amplitudes (The “Signature”.) • Compare to known acceptable standards or baselines (Note: Signature, Spectrum, and FFT (Fast Fourier Transform) are used synonymously.) CORRECTION • Take actions against offending vibration levels: Balancing Alignment Replacing defective bearings Tying down loose components Avoiding resonance The BIG 5! VERIFICATION • Perform a “Before and After” assessment • Did the follow-up action make the situation better? • If the problem has been addressed, set a new measurement baseline for the future Primary Goals of the PdM Program • • • • • • Ensure convenient rework Avoid panic Avoid secondary damage Promote safety Reduce repair time Avoid any unnecessary downtime 12 Steps for Success • • • • • • • • • Survey the plant in terms of critical, essential, balance of plant categories Choose the machines to put into the program Optimize measurements in terms of parameters and timing Choose the method and educate participants Set criteria (alarms) for assessment Baseline the machine under consideration thru 10, Setup, Measure, Store, Present (detection) Problem assessment (analysis) Correct the fault (correction) (After step 12, the process can be re-entered at step 6.) FFT (Spectrum) Measurement Typical Settings Menu TWF (Time Waveform) Measurement Typical Settings Menu Measurements at Instrument Time Waveform FFT Zoomed FFT on Instrument Shows more precise frequency and resolution Viewed at PC Note delta cursors to determine approximate frequency Wet End - Breast Roll - Tending Side Axial - Vel Time 400 ms 1/16/2008 10:14:34 AM Location Note (9/5/2007 12:34:27 PM) Cursor A: Cursor B: Diff: Diff: 0.08 0.037 secs 0.061 secs 0.025 secs 2435.714 CPM 0.075 in/s 0.074 in/s -0.001 in/s O/All 0.079 in/s 0-pk 0.06 0.04 in/s 0.02 -0.02 -0.04 -0.06 -0.08 0.05 1/16/2008 10:14:34 AM 0.1 0.15 O/All 0.079 in/s 0-pk 0.2 secs 0.25 0.3 0.35 0.4 Viewed at PC Interpolated running frequency Wet End - Breast Roll - Tending Side Axial - Vel Freq 60000 CPM 1/16/2008 10:40:31 AM Location Note (9/5/2007 12:34:27 PM) Cursor A: 0.08 2417.776 CPM 0.081 in/s O/All 0.083 in/s 0-pk 0.07 0.06 in/s 0-pk 0.05 0.04 0.03 0.02 0.01 0 10,000 1/16/2008 10:40:31 AM 20,000 O/All 0.083 in/s 0-pk 30,000 CPM 40,000 50,000 60,000 Setup Parameters - TWF Note the settings and calculated equivalent Fmax value and estimated time Setup Parameters - FFT Note the settings and estimated time Examples of Field Problems Ski-Slope - Poor Connection- Horizontal - Vel Spec 60000 CPM 8/30/2005 9:09:04 PM 0.012 O/All 0.015 in/s 0-pk 0.01 Loose or faulty connections 0.008 in/s 0-pk Ski-Slope due to poor connection across sensor/cable/vb Inspect the connections 0.006 0.004 0.002 Note the lowamplitude of all other frequencies 0 8/30/2005 9:09:04 PM 10,000 20,000 O/All 0.015 in/s0-pk 30,000 CPM 40,000 50,000 60,000 Examples of Field Problems Ski-Slope - Saturation- Horizontal - Vel Spec 60000 CPM 9/12/2005 9:29:25 PM O/All 2.156 in/s 0-pk 0.5 Impacting and saturation 0.4 0.3 in/s 0-pk Ski-Slope due to signal saturation (impacting of sensor) 0.2 Note the high O/All magnitude compared to the lowamplitude of all other frequencies 0.1 0 9/12/2005 9:29:25 PM 10,000 20,000 O/All 2.156 in/s0-pk 30,000 CPM 40,000 50,000 60,000 Example of Setup Issues Resolution - Low - Horizontal - Vel Freq 60000 CPM 7/24/2005 6:31:06 PM Cursor A: 3.5 5999.574 CPM orders 3.339 in/s O/All 3.34 in/s 0-pk Resolution - High - Horizontal - Vel Freq 60000 CPM 7/24/2005 6:31:17 PM 3.5 2.5 2.5 in/s 0-pk Cursor A: 5999.579 CPM 3.339 in/s O/All 3.339 in/s 0-pk Improved frequency resolution Resolution of 400 lines showing a broad based spectral element 1.5 in/s 0-pk Resolution of 3200 lines showing a narrow based spectral element 1.5 0.5 0.5 7/24/2005 6:31:06 PM 10,000 20,000 O/All 3.34 in/s 0-pk 30,000 CPM 5999.574 RPM 40,000 50,000 60,000 0 7/24/2005 6:31:17 PM 10,000 20,000 O/All 3.339 in/s 0-pk 30,000 CPM 40,000 50,000 60,000 Example of Good Data for Analysis Struct Looseness - 3-Pmp-DE - Vertical - Vel Spec 60000 CPM"hi res." 9/7/2005 3:58:28 PM Power (in/s 0-pk) 0.46 Cursor A: 0.18 1495.739 CPM 1.018 orders 0.126 in/s O/All 0.264 in/s 0-pk 0.16 0.14 Running speed in/s 0-pk 0.12 0.1 0.08 0.06 0.04 0.02 0 9/7/2005 3:58:28 PM 10,000 O/All 0.264 in/s0-pk 20,000 1470 RPM 30,000 CPM 40,000 50,000 60,000 Summary – Key Considerations • • • • • • • • • • Know the equipment and application Recognize changing conditions Choose the best shot at capturing the event Choose the best sensor for the job Choose the best location for the measurement Make appropriate settings for the measurement Capture good quality data Transform data to information Identify tell-tale signs of trouble Decide a course of action Concluding Remarks • Vibration is a primary measurement for an effective PdM program • Education and experience in the technology and techniques are essential for success • Get management ‘buy-in’ on the process • Know the equipment in terms of physical make-up and intended operation • Know standards for acceptable operation • Know the tell-tale signs for potential problems • Know the tools available for the program • Perform the proper setup for acquiring data • Be confident in assessing the situation • Have confidence in making the call for action Questions and/or Comments? Dennis Shreve dshreve@commtest.com ... machine being measured • Know the relative phase readings on key positions of the machine (This will show relative motion.) Key Measurement Parameters • • • • • • Time or frequency data to be captured... CPM 0.075 in/s 0.074 in/s -0.001 in/s O/All 0.079 in/s 0-pk 0.06 0.04 in/s 0 .02 -0 .02 -0.04 -0.06 -0.08 0.05 1/16 /2008 10:14:34 AM 0.1 0.15 O/All 0.079 in/s 0-pk 0.2 secs 0.25 0.3 0.35... CPM 1/16 /2008 10:40:31 AM Location Note (9/5/2007 12:34:27 PM) Cursor A: 0.08 2417.776 CPM 0.081 in/s O/All 0.083 in/s 0-pk 0.07 0.06 in/s 0-pk 0.05 0.04 0.03 0 .02 0.01 0 10,000 1/16 /2008 10:40:31