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6.08 Vibration Severity Chart How To Use This Severity Chart 1) 3-in-1 chart pl

6.08 Vibration Severity Chart How To Use This Severity Chart 1) 3-in-1 chart plots vibration measure and levels for: Acceleration vs. CPM, Velocity vs. CPM, and Displacement vs. CPM. 2) Knowing a machine’s RPM (i.e. CPM) and the vibration sensing technique (see table below), determine how the machine should perform when new (or rebuilt) and what level might warrant an ALERT or DANGER condition. 3) Simpliﬁ ed table below graph is offered for typical acceptance criteria for seismic (casing) and shaft proximity vibration. NOTES for determining a setpoint (e.g. alarm and/or danger limit) for machine protection monitoring: 1) Metrix Instrument Co. will not be held liable for setpoint determination. 2) Consult machinery manufacturer (OEM) for recommendations. They know their machinery best. 3) As a starting point only, the following is from over 30 years of company ﬁ eld experience and is offered free from charge. Seismic - on bearing case Common Measurand Application NEW ALERT DANGER Sensing Technique Rolling element brgs. Hydrodynamic, Journal Bearings Operating Speed* All < 4000 RPM 4K < RPM < 80K Non-contact Proximity (thru case) Gearmesh > 100,000 CPM Acoustic atop gears Velocity Acceleration Displacement .05 -.08 ips,pk 1-2 mm/s,RMS .2 - .3 ips,pk Typical Vibration Reading/Setpoints 3 - 8 g,pk 2 - 6 g,RMS 25 - 40 um, pk-pk .2 - .3 mil, pk-pk 1.0 - 1.5 mil, pk-pk 5 - 8 um, pk-pk 5-7 mm/s,RMS .08 -.12 ips,pk 2-3 mm/s,RMS 15 - 40 g,pk 10 - 25 g,pk 7 - 18 g,RMS 10-28 g,RMS .3 - .4 ips,pk 4-6 mm/s,RMS .3 - .4 ips,pk 7-10 mm/s,RMS .4 - .6 ips,pk 5-7 mm/s,RMS 75 - 100 um, pk-pk .8 - 1.2 mil, pk-pk 2.0 - 2.5 mil, pk-pk 3.0 - 4.0 mil, pk-pk 50 - 75 um, pk-pk 20 - 30 um, pk-pk .8- 1.2 mil, pk-pk *Refers to constant speed machines. For variable speed machines, velocity severity is constant. Note from the chart that the displacement and acceleration measureands vary with speed and are not normally used due to complex severity determination. 20 - 30 um, pk-pk VIBRATION FREQUENCY IN CPM (e. g. MACHINE RPM) VELOCITY mm/s (IPS) 250 (10) 25 (1) 2.5 (.1) .25 (.01) 12.5 (.5) 1.2 (.05) 125 (5) EXAMPLE FAN 230 cpm 100K ACCELERATION G, PK BAD ROUGH 25 (1) 125 (5) 50 (2) 250 (10) 2.5 (.1) .25 (.01) 2500 (100) 100G 1G .1G .01G .001G 1000 100 EXAMPLE FAN .02 g EXAMPLE FAN 7.5 mm/s (.3 ips), pk DESIRABLE ACCEPTABLE FAIR EXAMPLE FAN 625 um (25 mils) 2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 10G DISPLACEMENT um (MILS), PK-PK 25000 (1000) = 0.001 INCH (25.4 UM) = 10-6 M (0.03937 MIL) = 1 IN/SEC (25.4 MM/S) = 1 MILLIMETER/SEC = (0.03937 IPS) = ACCEL.DUE TO GRAVITY = 386 IN/SEC2 (9.81 M/S2) = 1 CYCLE PER MINUTE = CYCLES/SEC (HZ) X 60 = PK X .707 (FOR SINE WAVE) 1 MIL 1 UM 1 IPS 1 MM/S 1 G 1 CPM RMS REFERENCE MATERIAL www.metrix1.com • info@metrix1.com Sales & Service Tel: 281-940-1802 • Fax: 281-940-1799 • 05/07 Vibration - Condition Monitoring and Protection REFERENCE MATERIAL www.metrix1.com • info@metrix1.com Sales & Service Tel: 281-940-1802 • Fax: 281-940-1799 • 05/07 6.09 Charts & Guides Conversion Between °F and °C °C °F °C °F 273.15 268 262 251 240 212 184 169 157 129 101 73.3 62.2 53.9 51.1 40.0 28.9 23.3 20.6 17.8 459.67 450 440 420 400 350 300 273 250 200 150 100 80 65 60 40 20 10 5 0 459.7 418 328 238 148 112 85 76 40.0 4.0 14.0 23.0 32.0 °C °F °C °F - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + - - - - + 15.9 12.2 6.67 1.11 0.00 4.44 10.0 15.6 21.1 26.7 32.2 37.8 93.3 121 149 204 160 316 399 427 538 649 760 +5 10 20 30 32 40 50 60 70 80 90 100 200 250 300 400 500 600 750 800 1000 1200 1400 41.0 50.0 68.0 86.0 89.6 104.0 122.0 140.0 158.0 176.0 194.0 212.0 392 482 572 752 932 1112 1382 1472 1832 2192 2552 Relationships of Sinusoidal Velocity, Acceleration, Displacement = πfD = 61.44 g/f = 0.0511 f2D = 0.0162 Vf = 0.3183 V/f = 19.57 g/f2 = Inches pk-to-pk = Inches/second = Hz (cps) or RPM/60 = 386.1 In/sec2 ENGLISH = πfD = 1.56 g/f = 2.013 f2D = 0.641 Vf = 0.3183 V/f = 0.4968 g/f2 = meters pk-to-pk = meters/second = Hz (cps) or RPM/60 = 9.807 m/sec2 D V f g D V f g V V g g D D V V g g D D METRIC Constants for True Sine Waves Only rms value rms value peak value peak value average value average value peak-to-peak = 0.707 = 1.11 = 1.414 = 1.57 = 0.637 = 0.90 = 2.0 x peak value x average value x rms value x average value x peak value x rms value x peak value 0.0 0.05 0.1 0.5 1.0 IPS (in/sec) Velocity Machine tools (unloaded) & Steam Turbines Gear Boxes, Electric Motors & Pumps:Gear & Cent. Generators & Hammermill (unloaded) Cent. Compressors Fans & Blowers Conveyors Recips: Compressors, Pumps & Engines Packaging Machinery Crushers (unloaded) Vibration Warning Level Guide Vibration - Condition Monitoring and Protection uploads/Industriel/ vibration-guide.pdf