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GE Measurement & Control Beginner's Guide Machine Vibration Revision 24/09/2014 Beginner’s Guide to Machine Vibration GE Measurement & Control COPYRIGHT © 2014 GE Energy (New Zealand) Ltd. All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of GE Energy (New Zealand) Ltd. For information, contact: GE Energy Level 2, 22 Moorhouse Avenue Christchurch New Zealand Email:
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Beginner’s Guide to Machine Vibration GE Measurement & Control Contents Section 1: Why is Monitoring Vibration Important? ................................. 1 What is Machine Vibration? ..............................................................................1 What Causes Machine Vibration? .................................................................3 (a) Repeating Forces ........................................................................................ 3 (b) Looseness ...................................................................................................... 6 (c) Resonance ..................................................................................................... 6 Why Monitor Machine Vibration? ..................................................................8 (a) Severe Machine Damage ......................................................................... 9 (b) High Power Consumption...................................................................... 10 (c) Machine Unavailability ........................................................................... 11 (d) Delayed Shipments .................................................................................. 11 (e) Accumulation of Unfinished Goods .................................................... 12 (f) Unnecessary Maintenance .................................................................... 12 (g) Quality Problems ...................................................................................... 13 (h) Bad Company Image .............................................................................. 13 (i) Occupational Hazards ............................................................................. 14 Summary ................................................................................................................. 14 Section 2: How is Machine Vibration Described? .................................... 15 How is Vibration Described? ......................................................................... 16 What is Amplitude? ............................................................................................ 17 What is Frequency? ........................................................................................... 20 What is AWaveform? ....................................................................................... 21 What is ASpectrum? ......................................................................................... 22 Summary ................................................................................................................. 24 Section 3: How is Machine Vibration Measured? .................................... 25 Which Machines Need Monitoring? .......................................................... 26 How Does the Instrument Work? ............................................................... 27 How is the Accelerometer Mounted? ....................................................... 28 (a) Mount as Close as Possible to the Bearing ...................................... 29 (b) Make Sure the Accelerometer is Firmly Attached ......................... 30 (c) Make Sure the Accelerometer is Oriented Correctly ..................... 32 (d) Mount the Same Accelerometer in the Same Location ............... 34 (e) Mount the Accelerometer on Something Substantial .................. 35 (f) Take Care of the Accelerometer ........................................................... 35 (g) Take Care of Personal Safety ............................................................... 37 How are Parameters Set? ............................................................................... 38 (a) How Data is Collected ............................................................................ 39 (b) How Much or How Fast Data is Collected ........................................ 40 Beginner’s Guide to Machine Vibration GE Measurement & Control (c) How Data is Processed ........................................................................... 43 (d) How Data is Displayed ........................................................................... 45 How is Data Collected? .................................................................................... 48 Summary ................................................................................................................. 53 Appendix: List of Symbols ............................................................................ 54 Glossary Abbreviations Guide .................................................................... 56 Glossary of Terms ......................................................................................... 57
