1、BSI Standards PublicationBS ISO 21940-12:2016Mechanical vibration RotorbalancingPart 12: Procedures and tolerances forrotors with flexible behaviourBS ISO 21940-12:2016 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 21940-12:2016. It supersedes BS ISO 11342:19
2、98 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee GME/21/5, Mechanical vibration, shock and condition monitoring - Vibration of machines.A list of organizations represented on this committee can be obtained on request to its secretary.This publication
3、 does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2016.Published by BSI Standards Limited 2016ISBN 978 0 580 87801 5 ICS 21.120.40 Compliance with a British Standard cannot confer immunity fro
4、m legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 April 2016.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 21940-12:2016 ISO 2016Mechanical vibration Rotor balancing Part 12: Procedures
5、and tolerances for rotors with flexible behaviourVibrations mcaniques quilibrage des rotors Partie 12: Modes opratoires et tolrances pour les rotors comportement flexibleINTERNATIONAL STANDARDISO21940-12First edition2016-04-01Reference numberISO 21940-12:2016(E)BS ISO 21940-12:2016ISO 21940-12:2016(
6、E)ii ISO 2016 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posti
7、ng on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22
8、749 09 47copyrightiso.orgwww.iso.orgBS ISO 21940-12:2016ISO 21940-12:2016(E)Foreword vIntroduction vii1 Scope . 12 Normative references 13 Terms and definitions . 14 Fundamentals of dynamics and balancing of rotors with flexible behaviour . 24.1 General . 24.2 Unbalance distribution 24.3 Mode shapes
9、 of rotors with flexible behaviour 24.4 Response of a rotor with flexible behaviour to unbalance 34.5 Aims of balancing rotors with flexible behaviour . 44.6 Provision for correction planes 54.7 Coupled rotors . 55 Rotor configurations. 56 Procedures for balancing rotors with flexible behaviour at l
10、ow speed 76.1 General . 76.2 Selection of correction planes 86.3 Service speed of the rotor 86.4 Initial unbalance 86.5 Low-speed balancing procedures . 86.5.1 Procedure A Single-plane balancing 86.5.2 Procedure B Two-plane balancing 86.5.3 Procedure C Individual component balancing prior to assembl
11、y 96.5.4 Procedure D Balancing subsequent to controlling initial unbalance 96.5.5 Procedure E Balancing in stages during assembly 96.5.6 Procedure F Balancing in optimum planes .107 Procedures for balancing rotors with flexible behaviour at high speed .107.1 General 107.2 Installation for balancing
12、107.3 Procedure G Multiple speed balancing 117.3.1 General. 117.3.2 Initial low-speed balancing 117.3.3 General procedure .117.4 Procedure H Service speed balancing . 137.5 Procedure I Fixed speed balancing 147.5.1 General. 147.5.2 Procedure 148 Evaluation criteria .148.1 Choice of criteria 148.2 Vi
13、bration limits in the balancing machine . 158.2.1 Overview 158.2.2 General. 158.2.3 Special cases and exceptions 158.2.4 Factors influencing machine vibration 158.2.5 Critical clearances and complex machine systems168.2.6 Permissible vibrations in the balancing machine 168.3 Residual unbalance toler
14、ances . 178.3.1 Overview 178.3.2 General. 178.3.3 Limits for low-speed balancing 178.3.4 Limits for multiple speed balancing .18 ISO 2016 All rights reserved iiiContents PageBS ISO 21940-12:2016ISO 21940-12:2016(E)9 Evaluation procedures 189.1 Evaluation procedures based on vibration limits 189.1.1
15、Vibration assessed in a high-speed balancing machine 189.1.2 Vibration assessed on a test facility .199.1.3 Vibration assessed on site 199.2 Evaluation based on residual unbalance tolerances .209.2.1 General. 209.2.2 Evaluation at low speed 209.2.3 Evaluation at multiple speeds based on modal unbala
16、nces 209.2.4 Evaluation at service speed in two specified test planes .21Annex A (informative) Cautionary notes concerning rotors when installed in-situ 23Annex B (informative) Optimum planes balancing Low-speed three-plane balancing .24Annex C (informative) Conversion factors .26Annex D (informativ
17、e) Example calculation of equivalent residual modal unbalances 27Annex E (informative) Procedures to determine whether a rotor shows rigid or flexible behaviour 30Annex F (informative) Method of computation of unbalance correction 32Bibliography .33iv ISO 2016 All rights reservedBS ISO 21940-12:2016
18、ISO 21940-12:2016(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a su
19、bject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (
20、IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be
21、 noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identify
22、ing any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience
23、 of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supp
24、lementary informationThe committee responsible for this document is ISO/TC 108, Mechanical vibration, shock and condition monitoring, Subcommittee SC 2, Measurement and evaluation of mechanical vibration and shock as applied to machines, vehicles and structures.This first edition of ISO 21940-12 can
25、cels and replaces ISO 11342:1998, which has been technically revised. The main changes are deletion of the terms and definitions which were transferred to ISO 21940-2 and deletion of former Annex F which is a duplication of a part of D.1. It also incorporates the Technical Corrigendum ISO 11342:1998
26、/Cor.1:2000.ISO 21940 consists of the following parts, under the general title Mechanical vibration Rotor balancing: Part 11: Procedures and tolerances for rotors with rigid behaviour1) Part 12: Procedures and tolerances for rotors with flexible behaviour2) Part 13: Criteria and safeguards for the i
27、n-situ balancing of medium and large rotors3) Part 14: Procedures for assessing balance errors4) Part 21: Description and evaluation of balancing machines5)1) Revision of ISO 1940-1:2003 + Cor.1:2005, Mechanical vibration Balance quality requirements for rotors in a constant (rigid) state Part 1: Sp
28、ecification and verification of balance tolerances2) Revision of ISO 11342:1998 + Cor.1:2000, Mechanical vibration Methods and criteria for the mechanical balancing of flexible rotors3) Revision of ISO 20806:2009, Mechanical vibration Criteria and safeguards for the in-situ balancing of medium and l
29、arge rotors4) Revision of ISO 1940-2:1997, Mechanical vibration Balance quality requirements of rigid rotors Part 2: Balance errors5) Revision of ISO 2953:1999, Mechanical vibration Balancing machines Description and evaluation ISO 2016 All rights reserved vBS ISO 21940-12:2016ISO 21940-12:2016(E) P
30、art 23: Enclosures and other protective measures for the measuring station of balancing machines6) Part 31: Susceptibility and sensitivity of machines to unbalance7) Part 32: Shaft and fitment key convention8)The following part is under preparation: Part 2: Vocabulary9)6) Revision of ISO 7475:2002,
31、Mechanical vibration Balancing machines Enclosures and other protective measures for the measuring station7) Revision of ISO 10814:1996, Mechanical vibration Susceptibility and sensitivity of machines to unbalance8) Revision of ISO 8821:1989, Mechanical vibration Balancing Shaft and fitment key conv
32、ention9) Revision of ISO 1925:2001, Mechanical vibration Balancing Vocabularyvi ISO 2016 All rights reservedBS ISO 21940-12:2016ISO 21940-12:2016(E)IntroductionThe aim of balancing any rotor is to achieve satisfactory running when installed in-situ. In this context, “satisfactory running” means that
33、 not more than an acceptable magnitude of vibration is caused by the unbalance remaining in the rotor. In the case of a rotor with flexible behaviour, it also means that not more than an acceptable magnitude of deflection occurs in the rotor at any speed up to the maximum service speed.Most rotors a
34、re balanced in manufacture prior to machine assembly because afterwards, for example, there might be only limited access to the rotor. Furthermore, balancing of the rotor is often the stage at which a rotor is approved by the purchaser. Thus, while satisfactory running in-situ is the aim, the balanc
35、e quality of the rotor is usually initially assessed in a balancing machine. Satisfactory running in-situ is, in most cases, judged in relation to vibration from all causes, while in the balancing machine, primarily, once-per-revolution effects are considered.This part of ISO 21940 classifies rotors
36、 in accordance with their balancing requirements and establishes methods of assessment of residual unbalance.This part of ISO 21940 also shows how criteria for use in the balancing machine can be derived from either vibration limits specified for the assembled and installed machine or unbalance limi
37、ts specified for the rotor. If such limits are not available, this part of ISO 21940 shows how they can be derived from ISO 10816 and ISO 7919 if desired in terms of vibration, or from ISO 21940-11, if desired in terms of permissible residual unbalance. ISO 21940-11 is concerned with the balance qua
38、lity of rotating rigid bodies and is not directly applicable to rotors with flexible behaviour because rotors with flexible behaviour can undergo significant bending deflection. However, in this part of ISO 21940, methods are presented for adapting the criteria of ISO 21940-11 to rotors with flexibl
39、e behaviour.There are situations in which an otherwise acceptably balanced rotor experiences an unacceptable vibration level in situ, owing to resonances in the support structure. A resonance or near resonance condition in a lightly damped structure can result in excessive vibratory response to a sm
40、all unbalance. In such cases, it can be more practicable to alter the natural frequency or damping of the structure rather than to balance to very low levels, which might not be maintainable over time (see also ISO 21940-31). ISO 2016 All rights reserved viiBS ISO 21940-12:2016BS ISO 21940-12:2016Me
41、chanical vibration Rotor balancing Part 12: Procedures and tolerances for rotors with flexible behaviour1 ScopeThis part of ISO 21940 presents typical configurations of rotors with flexible behaviour in accordance with their characteristics and balancing requirements, describes balancing procedures,
42、 specifies methods of assessment of the final state of balance, and establishes guidelines for balance quality criteria.This part of ISO 21940 can also serve as a basis for more involved investigations, e.g. when a more exact determination of the required balance quality is necessary. If due regard
43、is paid to the specified methods of manufacture and balance tolerances, satisfactory running conditions can be expected.This part of ISO 21940 is not intended to serve as an acceptance specification for any rotor, but rather to give indications of how to avoid gross deficiencies and unnecessarily re
44、strictive requirements.Structural resonances and modifications thereof lie outside the scope of this part of ISO 21940.The methods and criteria given are the result of experience with general industrial machinery. It is possible that they are not directly applicable to specialized equipment or to sp
45、ecial circumstances. Therefore, in some cases, deviations from this part of ISO 21940 are possible.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited a
46、pplies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 192510), Mechanical vibration Balancing VocabularyISO 2041, Mechanical vibration, shock and condition monitoring VocabularyISO 21940-1111), Mechanical vibration Rotor balancing Part 1
47、1: Procedures and tolerances for rotors with rigid behaviourISO 21940-14, Mechanical vibration Rotor balancing Part 14: Procedures for assessing balance errorsISO 21940-32, Mechanical vibration Rotor balancing Part 32: Shaft and fitment key convention3 Terms and definitionsFor the purposes of this d
48、ocument, the terms and definitions given in ISO 1925 and ISO 2041 apply.10) To become ISO 21940-2 when revised.11) To be published.INTERNATIONAL STANDARD ISO 21940-12:2016(E) ISO 2016 All rights reserved 1BS ISO 21940-12:2016ISO 21940-12:2016(E)4 Fundamentals of dynamics and balancing of rotors with
49、 flexible behaviour4.1 GeneralRotors with flexible behaviour normally require multiplane balancing at high speed. Nevertheless, under certain conditions, a rotor with flexible behaviour can also be balanced at low speed. For high-speed balancing, two different methods have been formulated for achieving a satisfactory state of balance, namely modal balancing and the influence coefficient approach. The basic theory behind both of these methods and their relative merits
