1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 14839-4:2012Mechanical vibration Vibration of rotatingmachinery equipped withactive magnetic bearingsPart 4: Technical guidelinesBS ISO 14839-4:2012 BRITISH STANDARDNation
2、al forewordThis British Standard is the UK implementation of ISO 14839-4:2012. The UK participation in its preparation was entrusted to TechnicalCommittee GME/21/5, Mechanical vibration, shock and conditionmonitoring - Vibration of machines.A list of organizations represented on this committee can b
3、eobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012 ISBN 978 0 580 72050 5 ICS 17.160 Compliance
4、with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 April 2012. Amendments issued since publicationDate T e x t a f f e c t e dBS ISO 14839-4:2012 ISO 2012Mechanical vibration
5、 Vibration of rotating machinery equipped with active magnetic bearings Part 4: Technical guidelinesVibrations mcaniques Vibrations de machines rotatives quipes de paliers magntiques actifs Partie 4: Lignes directrices techniquesINTERNATIONAL STANDARDISO14839-4First edition2012-03-15Reference number
6、ISO 14839-4:2012(E)BS ISO 14839-4:2012ISO 14839-4:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including pho
7、tocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in Switzerla
8、ndBS ISO 14839-4:2012ISO 14839-4:2012(E) ISO 2012 All rights reserved iiiContents PageForeword . v1 Scope 12 Normative references . 13 Terms and definitions . 14 Active magnetic bearing system architecture . 25 Important differences between magnetic bearings and conventional bearings 35.1 Some advan
9、tages of active magnetic bearings 35.2 Some disadvantages of active magnetic bearings 55.3 Comparison among rolling, fluid film and magnetic bearings 66 System condition monitoring . 66.1 General . 66.2 Excess rotor shaft displacement (radial x, y, and axial z) . 66.3 Excess of rotor expansion 86.4
10、Overload of bearing (over current of bearing coil) . 86.5 Bearing temperature high . 86.6 Overspeed of rotor 86.7 Power supply defect . 86.8 Battery power defect 86.9 Controller temperature high . 86.10 Cooling . 97 Environmental factors 97.1 Introduction . 97.2 Environmental category tables 107.3 E
11、xplosive atmosphere types 138 System requirements .138.1 Estimation of bearing load 138.2 Limitation of dI/dt for laminated bearings .148.3 Balancing .168.4 Location of bearings and transducers 178.5 Fault recovery and fault handling .178.6 Signal processing .178.7 Monitoring system 179 Touchdown be
12、arings 189.1 Touchdown bearing requirements 189.2 Design of touchdown bearings189.3 Touchdown bearing monitoring 209.4 Touchdown test methods 2010 Preventive inspection .2210.1 Introduction2210.2 Regular inspection and maintenance 2210.3 Condition monitoring (recommendation) .2210.4 Inspection check
13、list 23Annex A (informative) Sizing of magnetic bearings 24Annex B (informative) Example of a design specification check list .27Annex C (informative) Example conditions for acceptance tests .29Annex D (informative) Touchdown test method example 30Annex E (informative) Example of system limitations
14、(current/voltage saturation) .32Annex F (informative) Unbalance control 35BS ISO 14839-4:2012ISO 14839-4:2012(E)iv ISO 2012 All rights reservedBibliography .40BS ISO 14839-4:2012ISO 14839-4:2012(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national
15、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 subject for which a technical committee has been established has the right to be represented on that committee. International
16、 organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules gi
17、ven in the ISO/IEC Directives, Part 2.The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least
18、75 % of the member bodies casting a vote.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 identifying any or all such patent rights.ISO 14839-4 was prepared by Technical Committee ISO/TC 108, M
19、echanical vibration, shock and condition monitoring, Subcommittee SC 2, Measurement and evaluation of mechanical vibration and shock as applied to machines, vehicles and structures.ISO 14839 consists of the following parts, under the general title Mechanical vibration Vibration of rotating machinery
20、 equipped with active magnetic bearings: Part 1: Vocabulary Part 2: Evaluation of vibration Part 3: Evaluation of stability margin Part 4: Technical guidelines ISO 2012 All rights reserved vBS ISO 14839-4:2012BS ISO 14839-4:2012Mechanical vibration Vibration of rotating machinery equipped with activ
21、e magnetic bearings Part 4: Technical guidelines1 ScopeThis part of ISO 14839:a) indicates a typical architecture of an active magnetic bearing (AMB) system so that users can understand which components are likely to comprise such systems and which functions these components provide;b) identifies th
22、e primary similarities and differences between AMB systems and conventional mechanical bearings;NOTE This information helps AMB system users better to understand the selection process and implications of transition to AMB technology.c) identifies the environmental factors that have significant impac
23、t on AMB system performance;d) identifies the operating limitations that are unique to AMB systems and defines standardized methods of assessing these limitations;e) identifies typical mechanisms for managing these limitations, especially rotor unbalance;f) provides considerations for the design and
24、 performance of touchdown bearing systems;g) defines a typical signal set for provision in an AMB system for proper system/process interface as well as condition and diagnostic monitoring;h) details current best practices for monitoring, operation and maintenance to achieve highest operational syste
25、m reliability;i) identifies typical fault-handling practices;j) recommends inspection and preventive maintenance processes for AMB systems.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited app
26、lies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 1940-1, Mechanical vibration Balance quality requirements for rotors in a constant (rigid) state Part 1: Specification and verification of balance tolerancesISO 14839-1:2002 + Amd.1:201
27、0, Mechanical vibration Vibration of rotating machinery equipped with active magnetic bearings Part 1: Vocabulary3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 14839-1 apply.INTERNATIONAL STANDARD ISO 14839-4:2012(E) ISO 2012 All rights reserved 1BS
28、ISO 14839-4:2012ISO 14839-4:2012(E)4 Active magnetic bearing system architectureActive magnetic bearings (AMBs) can be used as suspension elements in rotating machines in lieu of conventional types of bearings such as rolling element bearings and sleeve/journal bearings. AMBs support or levitate a s
29、haft using an electromagnetic force controlled by a position feedback loop. A typical radial magnetic bearing actuator consists of electromagnets arranged at four directions around a rotating shaft as shown in Figure 1. In this case, there are two orthogonal control axes.Key1 controller2 power ampli
30、fier3 magnetic coil4 displacement sensor5 rotor with rotational angular frequency Figure 1 Schematic drawing of a magnetic bearing systemKey elements of the AMB are:a) a displacement transducer that detects the displacement of the shaft from a reference position or setpoint;b) a processor or control
31、ler that produces a control command signal based on the position error;c) a power amplifier to convert the low level command signal to a control current;d) an electromagnetic actuator that applies a control force to the shaft based on the use of a magnetic field.Rotational drag losses are quite low
32、in an AMB because the shaft is supported by a magnetic field without mechanical contact. The only drag losses are from eddy currents generated in the rotor and from windage. These losses are small compared with the friction drag of rolling element bearings and very small compared to the losses in sl
33、iding bearings. On the other hand, control of shaft position is not trivial. The magnetic force acting on the shaft from each electromagnet is an attractive force that becomes larger as the shaft gets closer to the actuator (see Figure 2). Thus it is passively unstable since a displacement from the
34、equilibrium position results in a force pulling the shaft further from its equilibrium position. This force/displacement relationship is characterized by a negative stiffness.2 ISO 2012 All rights reservedBS ISO 14839-4:2012ISO 14839-4:2012(E)KeyF attractive force Fg, rrotor weightC clearance Clevle
35、vitation pointI = c current is constantFigure 2 Relationship between attractive force and clearance when the current is constantAMBs are operated with a bias flux produced either by the electromagnet or by a permanent magnet. This bias flux linearizes the force/control current relationship of the ma
36、gnetic bearing making position control easier. Historically, magnetic bearings were controlled by analogue control hardware executing single input single output (SISO) proportional, integral and differential actions (PID) control or simple multi-input multi-output (MIMO) PID schemes. Digital control
37、lers are used almost exclusively in new installations at the time of publication. Digital control provides all functionality available with the analogue control along with easier implementation and calibration.Further, many features became more practical with digital control, including robust contro
38、l techniques, unbalance response control, as well as monitoring and diagnostic functions. Generally, a digital controller for a magnetic bearing has a software control program running in a digital signal processor (DSP) that is essentially the same for all machine applications. Additionally, for a g
39、iven machine application, there are parameters that define the control law and other application-specific characteristics. Magnetic bearings are typically accompanied by touchdown bearings that support the shaft when power is turned off, in the event of an equipment failure during operation, or in c
40、ase an overload is applied to the bearing. The touchdown bearings are also commonly referred to as back-up bearings, auxiliary bearings, catcher bearings, and retainer bearings.The clearance between a touchdown bearing and the shaft is commonly set to less than or equal to half of the clearance betw
41、een a magnetic bearing and the shaft. The magnetic bearing that controls shaft position in the radial direction is called a radial magnetic bearing. A common arrangement of a magnetic bearing with displacement transducers and touchdown bearings is shown in Figure 3.On the other hand, a magnetic bear
42、ing that controls shaft position in the axial direction is called a thrust magnetic bearing, and a common configuration of this bearing, displacement transducer, and touchdown bearing is shown in Figure 4.5 Important differences between magnetic bearings and conventional bearings5.1 Some advantages
43、of active magnetic bearings5.1.1 A magnetic bearing system has many special features that differ from conventional bearings because it functions by supporting or levitating a shaft in a magnetic field controlled by position feedback. ISO 2012 All rights reserved 3BS ISO 14839-4:2012ISO 14839-4:2012(
44、E)Key1 shaft Cr 0,5r2 radial touchdown bearing Crradial clearance3 displacement sensor rradial magnetic gap4 radial magnetic bearingFigure 3 Typical arrangement of radial magnetic bearings, displacement transducers and touchdown bearings (ISO 14839-1:2002, Figure 6)Key1 thrust touchdown bearing Ca 0
45、,5a2 thrust displacement sensor Caaxial clearance3 thrust magnetic bearing aaxial magnetic gap4 thrust discFigure 4 Typical arrangement of thrust magnetic bearings, thrust displacement transducers and thrust touchdown bearings5.1.2 The following functions arise because the AMB uses an active control
46、 system:a) AMBs have high static stiffness and lower dynamic stiffness;4 ISO 2012 All rights reservedBS ISO 14839-4:2012ISO 14839-4:2012(E)b) AMBs typically use unbalance control techniques which can:1) minimize unbalance loads and transmitted vibration (using inertial axis rotation) or, 2) minimize
47、 harmonic displacement;c) AMB control can be used to increase damping when passing a critical speed;d) AMBs can be used for monitoring and diagnostic purposes due to built-in instrumentation.5.1.3 The following advantages of AMBs relative to conventional bearings arise because of the non-contact nat
48、ure of the AMB.a) There are no mechanical friction losses and only small electrical losses due to eddy currents, allowing AMB machines to have higher efficiency.b) Higher peripheral speeds are possible, typically limited only by rotor lamination stresses.c) There is no wear on the machine components
49、 (actuator and transducer), therefore there is no maintenance required for these components.5.1.4 There are the following advantages on the grounds that AMBs are used without lubrication.a) AMBs eliminate oil contamination problems.b) AMBs can be used in a vacuum.c) AMBs can be used in a cryogenic environment.d) Auxiliary lubricating systems, such as a hydraulic pump, an oil cooler, an oil filter, and piping of a hydraulic system, are unnecessary.e) The system can be made simpler and installation space can be sa
