Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com 13 Aberdeen Way Elgin, SC 29045 Tel. (803) 427-0791 Integrally Geared Centrifugal Air Compressor Vibration Analysis Case Studies 15-Feb-2008 By: Timothy S. Irwin, P.E. Senior Engineer tsi@mbesi.com Rotating Machinery Diagnostics & Instrumentation Solutions for… “Maintenance That Matters” www.mbesi.com M&B Engineered Solutions, Inc., 2007

Integrally Geared Air Compressors Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Integrally Geared Air Compressors How many of you have a Joy, (now Cameron) I-R Centac, Elliott PAP, Clark (Dresser-Rand) Isopac There are some differences in their designs, but there are more similarities especially for PdM monitoring and vibration/condition analysis © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Integrally Geared Air Compressors Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Integrally Geared Air Compressors How do we monitor these types of machines? What kind of components are we trying to monitor in these machines? High speed gearing High speed shafts / impellers Low speed shafts Geared couplings Disc or shim-pack couplings Sleeve bearings Multi-segment tilt pad bearings This does not include the driver which could be a motor or turbine of which either one can add more complexities to the setup of a monitoring route © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Integrally Geared Air Compressors Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Integrally Geared Air Compressors What parameters do we have available for monitoring the overall condition? Bearing temperatures Stage and drive gear vibration Stage inlet and outlet temperatures Stage inlet and outlet pressures Intercooler inlet and outlet temperatures Intercooler inlet and outlet pressures Motor amperage or kW There are a lot of parameters that can be used including the above items and: Performance testing Oil Analysis And visual inspections There are a lot of things to look at for an overall condition. Changes in any of the above items can be a significant indicator of the changing condition of the machine with clues as to what happened © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Integrally Geared Air Compressors Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Integrally Geared Air Compressors What do we use to monitor the vibration of the machine? Is there a permanent probe of some kind on each stage? Is there a permanent monitoring / vibration protection system installed? Or are our only options temporary accelerometers? Many permanent monitoring systems will have proximity probes on each stage, are they? A single probe on the stage? Dual probes at 90 degrees? Any there permanent accelerometers? Can you ‘plug-in’ to obtain the raw signal in your portable data collector? Many Metrix proximity transmitters do have a test connection There are a lot of considerations to obtaining the most effective data that you can use Find out what you have and use what you can. © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Integrally Geared Air Compressors Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Integrally Geared Air Compressors Vibration Analysis: Proximity probe use Magnetically mounted accelerometers High Frequency accelerometers To use the above probes we need to figure out the expected fault frequencies So that we can set up the appropriate frequency spans and resolutions The following segments of the case studies will be on several Joy (Cameron Compression) MSG 4-stage machines For today’s discussion lets take a closer look at the vibration analysis of one of these compressors Lets look at an example compressor © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #1 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #1 – Cameron Compression MSG What are typical Fault Frequencies: Shaft Running Speeds Journal Bearing Issues Gear Mesh (and other gear fault frequencies) Vane Pass (diffuser vs. impeller) Coupling/Alignment Motor Shaft Running Speeds Journal Bearing Issues Electrical Frequencies These are jus the general items © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #1 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #1 – Cameron Compression MSG Example Fault Frequencies: Shaft Speeds: Motor, Couplings, & Gear – 1781 rpm Pinion Speeds – 14,385 & 21,372 rpm Gears (420 teeth, 52 teeth, 35 teeth): Gear Mesh – 748,020 (12,467 Hz) Assembly phase – 187,000 & 21,372 cpm Hunting Tooth – 1198, 203 cpm Vane Pass – 362,100 cpm (for bladed diffuser) Lets look at a few of these numbers for a general idea of the ranges that we have to work in. So remember, you may have to take multiple data sets, be prepared to do high frequency analysis © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #1 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #1 – Cameron Compression MSG Displacement – Velocity – Acceleration What is an acceptable measurementfrequency range: 3600 rpm 20,000 rpm 750,000 cpm Displacement (mils) 1 1 1 Velocity (in/s) 0.19 1.05 39.3 Acceleration (g) 0.18 5.68 7988 3600 rpm 20,000 rpm 750,000 cpm Displacement (mils) 27 0.88 0.0006 Velocity (in/s) 5.1 0.921 0.025 Acceleration (g) 5 5 5 © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #1 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #1 – Cameron Compression MSG Lets look at some trends and stuff that you might see: Within 2 weeks after starting a machine after a major refurbishment: Note the step changes in the trend plot © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #1 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #1 – Cameron Compression MSG Here is one year’s worth of trend from that stage: Note the variations in amplitude over time © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #1 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #1 – Cameron Compression MSG Here is a recent comparison to the other stages on the same machine © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #1 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #1 – Cameron Compression MSG These are initial spectrums and waveforms Just after the startup © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #1 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #1 – Cameron Compression MSG Primary change is in ‘1X’ This is only 6 days later © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #1 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #1 – Cameron Compression MSG P-P Displacement in Mils Frequency in kCPM NER - #6 JOY #6 AIRCOMP-P2B PANEL POINT TWO 2ND STAGE BOTTOM 30 60 90 120 Max Amp .86 Plot Scale 0.9 11:17:33 13-Sep-07 14:47:17 08-Oct-07 09:20:50 20-Nov-07 08:59:07 10-Dec-07 15:41:50 07-Jan-08 Freq: Ordr: Sp 1: 19.05 1.004 .862 Basically the changing amplitude is ‘1X’ What can change in the ‘1X’; the balance condition as the impeller fit slips on the pinion 1X Amplitudes at different samples: 0.793; 0.851; 0.709; 0.713; 0.862 © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #1 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #1 – Cameron Compression MSG Note the lack in change of the multiples during the coast down © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #2 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #2 – Cameron Compression MSG Lets look at another machine with some different data: Lets look at some comparisons of data formats and frequency spans Here is a High and Standard Freq comparison at ‘standard frequencies’ Note the difference in the noise floor of a 10 mV/g vs. 100 mV/g © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #2 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #2 – Cameron Compression MSG © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #2 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #2 – Cameron Compression MSG Here are the immediate multiples © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #2 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #2 – Cameron Compression MSG Expanded Frequency Span to 20 kHz Now we are at 20 kHz Frequency Span © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #2 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #2 – Cameron Compression MSG Look at how the standard frequency accel drops off Now we are at 50 kHz © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #2 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #2 – Cameron Compression MSG From High Freq accel Are the overall amplitudes really higher than expected? © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #2 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #2 – Cameron Compression MSG The bottom one is about 1 revolution of the pinion The middle is about 4 revolutions This data is showing me the actual amplitudes as opposed to the calculated values in the spectral data Differing time frames from the high frequency accel © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #3 – Cameron Compression MSG Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #3 – Cameron Compression MSG Raw Timebase or Waveform High Frequency Enveloping A couple of reasons for these two plots Note that this data was taken using a different PdM system Different amplitude levels from other system Note that a bull gear ‘fault’ is showing up on the enveloped data, but not on the standard data. Time frames are different – but 3600 rpm is 0.0167 sec per rev, so there should have been 4 peaks of bull gear rotation © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #4 – Ingersoll-Rand Centac II Note the amplitudes © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008

Case Study #4 – Ingersoll-Rand Centac II Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #4 – Ingersoll-Rand Centac II 2X of gear mesh is higher than 1X; Sidebands are bullgear speed © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Case Study #4 – Ingersoll-Rand Centac II Transient Vibration Analysis- Insights into Machinery Behavior By Stanley R. Bognatz, P.E. 75 Laurel Street, Carbondale, PA 18407 Tel. (570) 282-4947 email: srb@mbesi.com Case Study #4 – Ingersoll-Rand Centac II Vane pass multiples are highest amplitudes © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008 M&B Engineered Solutions, Inc., 2007

Thank You – Any Questions? © 2008 M&B Engineered Solutions, Inc. www.mbesi.com Integrally Geared Air Compressor Case Studies Vibration Institute Piedmont Chapter Meeting Augusta, GA 15-Feb-2008