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1、INTERNATIONAL STANDARD ISO 14839-2 First edition 2004-09-01 Reference number ISO 14839-2:2004(E) ISO 2004 Mechanical vibration Vibration of rotating machinery equipped with active magnetic bearings Part 2: Evaluation of vibration Vibrations mcaniques Vibrations de machines rotatives quipes de palier
2、s magntiques actifs Partie 2: valuation des vibrations Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Hong Kong Polytechnic Univ/9976803100 Not for Resale, 04/17/2007 10:08:16 MDTNo reproduction or networking permitted without license from IH
3、S -,-,- ISO 14839-2:2004(E) ii ISO 2004 All rights reserved PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the
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6、m the Central Secretariat at the address given below. ISO 2004 All 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 photocopying and microfilm, without permission in writing from ei
7、ther ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland Copyright International Organization for Standardiza
8、tion Provided by IHS under license with ISO Licensee=Hong Kong Polytechnic Univ/9976803100 Not for Resale, 04/17/2007 10:08:16 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 14839-2:2004(E) ISO 2004 All rights reserved iii Contents Page 1Scope 1 2Normative references 1
9、 3Measurement and evaluation procedures . 1 4Evaluation criteria 6 Annex A (informative) Case study on an LP centrifugal compressor equipped with active magnetic bearings (AMBs) 8 Annex B (informative) Case study on current evaluation . 14 Annex C (informative) Voltage saturation . 17 Bibliography .
10、 20 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Hong Kong Polytechnic Univ/9976803100 Not for Resale, 04/17/2007 10:08:16 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 14839-2:2004(E) iv ISO 2004 All rights
11、reserved Foreword ISO (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 subject for
12、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 (IEC) on al
13、l matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given 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
14、circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 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 res
15、ponsible for identifying any or all such patent rights. ISO 14839-2 was prepared by Technical Committee ISO/TC 108, Mechanical vibration and shock, Subcommittee SC 2, Measurement and evaluation of mechanical vibration and shock as applied to machines, vehicles and structures. ISO 14839 consists of t
16、he following parts, under the general title Mechanical vibration Vibration of rotating machinery equipped with active magnetic bearings: Part 1: Vocabulary Part 2: Evaluation of vibration The following part is under preparation: Part 3: Evaluation of stability margin. Copyright International Organiz
17、ation for Standardization Provided by IHS under license with ISO Licensee=Hong Kong Polytechnic Univ/9976803100 Not for Resale, 04/17/2007 10:08:16 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 14839-2:2004(E) ISO 2004 All rights reserved v Introduction This part of I
18、SO 14839 concerns steady-state values of rotor vibrations and the AMB coil currents and voltage measured during nominal steady-state operation, but not the transient condition while passing critical speeds. The regulations of these transient vibrations passing at the critical speeds are established
19、in ISO 10814 in which the modal sensitivity, the so-called amplification factor (Q-factor), is then evaluated. This topic is beyond the scope of this part of ISO 14839. Because of the stiff support of oil-film bearings with small clearances e.g. bearing radial clearance () divided by the journal rad
20、ius , , shaft vibration should be regulated within low levels to avoid oil-film rupture of the lubricant and metal contact inside the bearing. In contrast, the relatively soft support of AMBs and correspondingly large clearances (e.g. ), a larger vibration level is often observed in AMB rotors, but
21、is quite normal and acceptable. The lower stiffness introduces no major problems in the transmission force to the machine foundation. Compared to the oil-film bearing rotor standards (see the ISO 7919-1 series), this part of ISO 14839 provides greater values of zone limits for vibration assessment a
22、nd acceptance. C (R) C/R 0,001 C/R 0,005 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Hong Kong Polytechnic Univ/9976803100 Not for Resale, 04/17/2007 10:08:16 MDTNo reproduction or networking permitted without license from IHS -,-,- . vi C
23、opyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Hong Kong Polytechnic Univ/9976803100 Not for Resale, 04/17/2007 10:08:16 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARDISO 14839-2:2004(E) ISO 20
24、04 All rights reserved 1 Mechanical vibration Vibration of rotating machinery equipped with active magnetic bearings Part 2: Evaluation of vibration 1Scope This part of ISO 14839 sets out general guidelines for measuring and evaluating rotating machinery equipped with active magnetic bearings (AMBs)
25、 with respect to the following two indices: shaft vibratory displacement measured at or close to the AMBs, and working current and voltage measured in magnetic coils or power supply amplifiers. Both indices are measured under nominal operating conditions in house and/or on site. These guidelines are
26、 presented in terms of both steady-state running values of these indices and any magnitude changes which may occur in these steady-state operations. This part of ISO 14839 is applicable to industrial rotating machines generating or consuming nominal power greater than , and is not limited by size or
27、 operational rated speed (i.e. comprising turbo-compressors, turbo-pumps, steam turbines, turbo-generators, turbo-fans, electric drives and other rotors supported by AMBs). This part of ISO 14839 establishes the vibration, current and voltage evaluation of the rotating machinery equipped with AMBs,
28、specified by a comparatively large power capacity as described above, excluding small- scale rotors such as turbo-molecular pumps, spindles and flywheels. This part of ISO 14839 covers both AMB-equipped rigid rotors and AMB-equipped flexible rotors. 2Normative references The following referenced doc
29、uments are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 7919-1, Mechanical vibration of non-reciprocating machines Measurements o
30、n rotating shafts and evaluation criteria Part 1: General guidelines 3Measurement and evaluation procedures 3.1Description of rotor-AMB system A typical rotor system supported by AMBs is illustrated in Figure 1. An AMB is located at each end of the shaft and includes an adjacent displacement transdu
31、cer and an emergency (auxiliary) ball bearing. The axial AMB is omitted in this figure. The control network for driving the AMB device is shown in Figure 2. As shown in these figures, each displacement transducer detects the shaft journal position at the bearing locations and its signal is fed back
32、to the controller. Deviation from the bearing centre is delivered to the controller. This controller might, for example, implement a proportional, integral and differential actions (PID) control algorithm. The controller drives the power amplifiers to supply the coil current. If the shaft moves down
33、ward, the upper electromagnetic coil is activated to lift the rotor upward by the magnetic force. Since, in this manner, the magnetic force acts 15 kW Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Hong Kong Polytechnic Univ/9976803100 Not fo
34、r Resale, 04/17/2007 10:08:16 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 14839-2:2004(E) 2 ISO 2004 All rights reserved upon the shaft so as to maintain the shaft at the neutral position inside the bearing, the AMB accomplishes both levitation and vibration control
35、 without mechanical contact. 3.2Displacement Throughout this part of ISO 14839, the term “vibratory displacement” refers to the total displacement of the shaft from the bearings centre, including any static displacement. The vibration measurement of the stationary parts of the machine (e.g. bearing
36、housing) is excluded from this part of ISO 14839. AMB equipment in rotating machines has its own displacement transducers for detecting shaft movement, and , as shown in Figure 3. No additional displacement transducers are required. The detected values of shaft vibratory position by these displaceme
37、nt transducers is the subject of this part of ISO 14839. Key 1AMB 2displacement transducer 3touch-down bearing 4clearance Figure 1 Rotor system equipped with active magnetic bearings x(t) y(t) Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Ho
38、ng Kong Polytechnic Univ/9976803100 Not for Resale, 04/17/2007 10:08:16 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 14839-2:2004(E) ISO 2004 All rights reserved 3 Key 1AMB 2displacement transducer 3power amplifier 4controller 5journal position signal 6reference sign
39、al Figure 2 Layout of AMB control network Key 1casing 2shaft 3displacement transducers Figure 3 Displacement transducers of AMBs Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Hong Kong Polytechnic Univ/9976803100 Not for Resale, 04/17/2007 1
40、0:08:16 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 14839-2:2004(E) 4 ISO 2004 All rights reserved As shown in Figure 3, the displacement transducers are oriented in the and directions at each radial bearing. The signals from these displacement transducers indicate
41、the rotor journal position including the d.c. component (eccentricity) and a.c. component (vibration orbit) as shown in Figure 4. Eccentricities from the clearance centre of the AMB (designated OO ) in the and directions are designated , while the vibration orbit amplitudes in the and directions are
42、 designated . The maximum displacement of the rotor from the clearance centre of the radial AMB, designated , can be calculated from Equation (1) exactly (1) or approximated by Equation (2), based on the orbit observation: (2) where This formula to estimate the maximum displacement in a certain dire
43、ction will generally overestimate the exact value with a maximum error of approximately . The evaluation of from Equation (1) and (2) using the signals measured by two displacement transducers is relatively complex. A digital oscilloscope or other special instrument is required. As a simpler procedu
44、re, the maximum value of the displacement values measured in two orthogonal directions is recommended as shown in Figure 4, based on the waveform observation: (3) This equation will, in general, underestimate the displacement. Any of these three displacement quantities may be agreed upon as the meth
45、od of characterizing the maximum displacement . In order to avoid contact problems between the rotor and stators, the following formula should be satisfied with a certain margin against the minimum radial clearance : (4) This is the index used to evaluate the clearance margin in this part of ISO 148
46、39. For assessment in this part of ISO 14839, the axial movement, , of the rotor is measured to compare with the minimum axial clearance in the same manner as shown in Figure 4. In this case: (5) These measurements considering the radial and axial directions should be made under agreed conditions ov
47、er the operational speed and load ranges of the machine. These measurements should typically be made after achieving agreed thermal and operating conditions. It should be noted that these indexes are measured only for the specified steady-state conditions including nominal slow changes in load. In a
48、ddition, measurements may also be taken when different conditions exist or during transient changes, for example, during slow roll, warming-up speed, critical speeds or shut down. However, the result of these measurements may not be suitable for this evaluation. xy j xyx,y xyax,ay Dmax Dmax=max ? x2(t)+ y2(t) ? Dmax ? x2 max+ y 2 max xmax= x+ ax ymax= y+ ay 40 % Dmax Dmax?maxxmax,ymax Dmax Cmin-radial Dmax