© DLI Engr Corp - Mike Cannon DLI Engineering Corp Vibration Analysis: Automated Diagnostics Diagnostic System Development © DLI Engr Corp - Large machine database, combined with years of repair history, and machine life cycle data is foundation for diagnostic system success 25,000+ machines in database (since 1972 ) Rules continuously verified & updated New rules added as unique machines join database Fault diagnoses analytically & empirically derived © DLI Engr Corp - Keys to a successful program… Ensure reliable and complete data collected Ensure you get answers, not just data Ensure you get First Rate support and training Use the right technology for the right application Distribute the information everywhere it is needed for planning of repairs Reliable and complete data © DLI Engr Corp - 100 100 100 100 WATCHMAN WATCHMAN TEST TEST POINT POINT DO DO NOT NOT PAINT PAINT Triaxial Sensor All axes - more complete analysis Improves accuracy of diagnosis Permanently Mounted Stud Excellent frequency response Repeatability = accurate trending Barcoding Faster and more accurate Prevents human error Processing Vibration Data Level LevelI I Reports Reports Level LevelIIII Trends Trends © DLI Engr Corp - Level LevelIIIIII Signatures Signatures Level - Reports © DLI Engr Corp - Discussion: Raw diagnostic report 93% of erroneous analysis was in stating the severity level Diagnostic software best equipped to identify obvious faults and additional faults (complete picture) Discussion: Engineers 67% of missed faults were where there was more than one fault, (missed multiple fault diagnosis) Tended to identify the obvious fault only EXTREME Level - Trends Increased Frequency of Data Collection SLIGHT Replaced Bearing Greased Bearing JAN © DLI Engr Corp - FEB MAR APR MAY JUN = Motor Bearing Wear JUL AUG SEP OCT NOV DEC JAN FEB Level - Signatures © DLI Engr Corp - Tri-axial Tri-axial Tri-axial Display Display Display Single Single axes axes Display Display Incoming Incoming Spectra Spectra How does the Diagnostic System work? What What machine machine is is this this Machinery Machinery Knowledge Knowledge Base Base MACHINE: MAIN CONDENSATE PUMP (TD) 61,62,63,64 SHIP APPLICABILITY: 1B,2B,3B,4B CVN63 UNITS: DRIVER © DLI Engr Corp - CID#: 05790037 MFR DWG#: 347-2918 MFR: WHITON HP: 40 STEAM CONDITIONS: Chest: 575 PSIG Exhaust: 15 PSIG RPM: 6410 TYPE: HELICAL FLOW, IMPULSE INTERMEDIATE CID : 05790037 TECH MANUAL : 347-2918 MFR: WHITON RATIO: 5.479 TO RPM (INPUT/OUTPUT): 6410/1170 TYPE: SINGLE HELICAL, DOUBLE REDUCTION TEST RPM’s AND OPERATING CONDITIONS TURBINE: 6400 PUMP: 1168 SWAB: 255-5 MID: 53 DATE: DECEMBER 1992 DRIVEN CID : 016000340 TECH MANUAL : 347-2918 MFR: ALLIS CHALMERS 595 GPM @ 65 PSIG OUTPUT: RPM: 1160 TYPE: DOUBLE STAGE, SINGLE SUCTION, VOLUTE ANALYSIS RANGES REF RPM: ORDERS: FREQ HZ : X TURBINE 2, 100 220, 11000 How does the Diagnostic System work? Incoming Incoming Spectra Spectra What What machine machine is is this this & what are its vibration sources? Machinery Machinery Knowledge Knowledge Base Base VIBRATION SOURCE COMPONENTS DRIVER ITEM t Z1 T1 S1 G1 © DLI Engr Corp - 10 A B DESCRIPTION INTERMEDIATE OR AUXILIARY SHAFTS ELEM Turbine Shaft (ref) Nozzles 90 Degree Spacing Turbine Blading Reversing Chambers 12.6 Degree Spacing 10.5 Degree Spacing 8.3 Degree Spacing High Speed Drive Pinion BEARING SKF 6211 SKF 6211 FUNCTION R,T-t R-t ORDER ITEM 1.00t I 40 3.00t 4.00t 40.00t G2 G3 G5 27 28.60t 34.20t 43.40t 27.00t G6 OP o C D DESCRIPTION ELEM Intermediate Shaft High Speed Driven Gear Low Speed Drive Pinion Oil Pump Drive Pinion BEARING ND 41308 ND 41308 FUNCTION R,T-i R, T-i ORDER ITEM DESCRIPTION 0.41t p 66 29 25 27.00t 11.86t 10.23t G4 P1 P2 Low Speed Driven Gear 2nd Stage Impeller Vanes 1st Stage Impeller Vanes 81 12 10.23t 1.52t E F G H J BEARING TMK 7320 TMK 7320 MRC 7308 MRC 7308 Journal Oil Pump Shaft Oil Pump Driven Gear Oil Pump DRIVEN ELEM Pump Shaft ORDER 0.18t 0.13t FUNCTION R,T-p R,T-p R,T-p R,T-p R-p 65 5 11.86t 0.91t 0.91t © DLI Engr Corp - 46 Low Range 3-axis Sample Spectra © DLI Engr Corp - 47 Data flow Methodology Basis 3: Order Normalized Vibration Data The expert system automatically finds the running speed of each machine © DLI Engr Corp - 48 Order normalizing allows Analyst or expert system quickly identify peaks The expert system readily identifies probable bearing tones and detects rotational rate sidebands Most important, it allows The creation of an average data file Combining Vibration signatures for identical machines different times slightly different operating speeds Methodology Basis 3: Order Normalized Vibration Data © DLI Engr Corp - 49 Uses least squares fit between Peaks in the Current data and Reference peaks Faultcodes average peaks © DLI Engr Corp - 50 Data flow Methodology Basis 4: Averaged Vibration Data Accumulated average data is the baseline for automated analysis © DLI Engr Corp - 51 Allows the machines themselves to define an acceptable level of vibration Composed of normalized vibration signatures of: relatively healthy machines physically identical machines © DLI Engr Corp - 52 Data flow Methodology Basis 5: Vibration Data Screening Screening routine incorporated by an expert system produces a screening output table which includes the following information for each test location and axis: Amplitudes at each of ten pre-selected, specified orders, (screening criteria or fault codes) Amplitude and rotational rate order of : the two highest peaks in each of the low range and high range spectra, excluding the ten specified peaks “Floor” level below which are the amplitudes of 75% of the remaining spectral lines of the high range spectrum For each of the above, © DLI Engr Corp - 53 1x and 2x (one and two times rotational rate), MB (motor bar pass rate) PV (pump vane rate) GR (reduction gear mesh rate) FDN (foundation resonance) change in amplitude deviation from average plus sigma Thus we have 14 distinct peaks plus the “floor” noise level tabulated for each axis © DLI Engr Corp - 54 Screening Sheet Example Methodology Basis 6: Cepstrum Analysis for Bearing Wear Detection © DLI Engr Corp - 55 Developed to detect and identify harmonics and sidebands, Finds any significant series of regularly spaced peaks in the frequency spectrum A cepstrum can be defined simply as the spectrum of a spectrum Characteristic peaks in the cepstral data occur at positions corresponding to frequencies at which there exists a strong series of peaks or spacings in the spectrum A machine with a faulty antifriction bearing may show a harmonic series of peaks with 3.12 times rotational rate spacings in the spectral data (i.e peaks at 3.12,6.24,9.36 etc.) This series of peaks would then show up in the cepstral data as a single peak at a position corresponding to the frequency of 3.12 times rotational rate Methodology Basis 7: Analysis by Component © DLI Engr Corp - 56 Close-Coupled Machines Turbines Motors Gearboxes Linked Drives (belt or chain) Centrifugal Pumps Rotary Thread/Gear Pumps Rotary Sliding Vane Pumps Reciprocating Pumps Fans Centrifugal Compressors Reciprocating Compressors Screw Compressors Lobed Blowers Generators Purifiers Couplings Diesel Engines Marine Propulsion Gearboxes Machine Tool Spindles Diagnostic Fault Templates / Data Flow COMPONENT CODES MOTOR FAULT TEMPLATES CSDM SCREENING OUTPUT TABLE COUPLING CSDM MACHINE MACHINE DATA DATA © DLI Engr Corp - 57 CENTRIFUGAL PUMP CSDM (CSDM = Component Specific Data Matrix) © DLI Engr Corp - 58 Diagnostic Rule-base © DLI Engr Corp - 59 Rule template example ...Diagnostic System Development © DLI Engr Corp - Large machine database, combined with years of repair history, and machine life cycle data is foundation for diagnostic system... Reports Level LevelIIII Trends Trends © DLI Engr Corp - Level LevelIIIIII Signatures Signatures Level - Reports © DLI Engr Corp - Discussion: Raw diagnostic report 93% of erroneous analysis... DRIVER © DLI Engr Corp - CID#: 057 90037 MFR DWG#: 347-2918 MFR: WHITON HP: 40 STEAM CONDITIONS: Chest: 575 PSIG Exhaust: 15 PSIG RPM: 6410 TYPE: HELICAL FLOW, IMPULSE INTERMEDIATE CID : 057 90037