1、BRITISH STANDARD BS ISO 14839-2:2004 Mechanical vibration Vibration of rotating machinery equipped with active magnetic bearings Part 2: Evaluation of vibration ICS 17.160 BS ISO 14839-2:2004 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 13
2、 October 2004 BSI 13 October 2004 ISBN 0 580 44580 1 National foreword This British Standard reproduces verbatim ISO 14839-2:2004 and implements it as the UK national standard. The UK participation in its preparation was entrusted by Technical Committee GME/21, Mechanical vibration and shock, to Sub
3、committee GME/21/5, Vibration of machines, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be foun
4、d in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are respo
5、nsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep t
6、he UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to v, a blank page, pages 1 to 20, an inside back cover and a back cover. The B
7、SI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsINTERNATIONAL TSDNARAD ISO 12-9384 iFtsr deoitin 24000-90-1 Reference number ISO 14839-2:2004(E) Mechanical vibration Vibration of rotating machinery eq
8、uipped with active magnetic bearings Part 2: Evaluation of vibration Vibrations mcaniques Vibrations de machines rotatives quipes de paliers magntiques actifs Partie 2: valuation des vibrationsINTERNATIONAL STANDARD ISO 14839-2 First edition 2004-09-01 Refecnern emureb OSI 13842-9002:)E(4 ceMhacinan
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13、ts Page 1 Scope 1 2 Normative references 1 3 Measurement and evaluation procedures . 1 4 Evaluation 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 (informa
14、tive) Voltage saturation . 17 Bibliography . 20 BSISO148392:2004iv 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
15、 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 organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with
16、 the International Electrotechnical Commission (IEC) on all 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 Intern
17、ational Standards adopted by the technical committees are 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
18、be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO14839-2 was prepared by Technical Committee ISO/TC108, Mechanical vibration and shock, Subcommittee SC 2, Measurement and evaluation of mechanical vibration and shock as applied to ma
19、chines, vehicles and structures. ISO 14839 consists of the 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: Evaluat
20、ion of stability margin. BSISO148392:2004 v Introduction This part of ISO 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 the
21、se transient vibrations passing at the critical speeds are established 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
22、 clearances e.g. bearing radial clearance ( ) divided by the journal radius , , 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
23、 (e.g. ), a larger vibration level is often observed in AMB rotors, but 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
24、 14839 provides greater values of zone limits for vibration assessment and acceptance. C (R) C/R 0,001 C/R 0,005 BSISO148392:2004blankANRETNIITOTS LANDNADRA OSI -938414002:2)E(Mechanical vibration Vibration of rotating machinery equipped with active magnetic bearings Part 2: Evaluation of vibration
25、1S c o p e This part of ISO 14839 sets out general guidelines for measuring and evaluating rotating machinery equipped with active magnetic bearings (AMBs) with respect to the following two indices: shaft vibratory displacement measured at or close to the AMBs, and working current and voltage measur
26、ed in magnetic coils or power supply amplifiers. Both indices are measured under nominal operating conditions in house and/or on site. These guidelines are presented in terms of both steady-state running values of these indices and any magnitude changes which may occur in these steady-state operatio
27、ns. 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 operational rated speed (i.e. comprising turbo-compressors, turbo-pumps, steam turbines, turbo-generators, turbo-fans, electric drives and other
28、 rotors supported by AMBs). This part of ISO 14839 establishes the vibration, current and voltage evaluation of the rotating machinery equipped with AMBs, specified by a comparatively large power capacity as described above, excluding small- scale rotors such as turbo-molecular pumps, spindles and f
29、lywheels. This part of ISO 14839 covers both AMB-equipped rigid rotors and AMB-equipped flexible rotors. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the
30、 latest edition of the referenced document (including any amendments) applies. ISO 7919-1, Mechanical vibration of non-reciprocating machines Measurements on rotating shafts and evaluation criteria Part 1: General guidelines 3 Measurement and evaluation procedures 3.1 Description of rotor-AMB system
31、 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 transducer and an emergency (auxiliary) ball bearing. The axial AMB is omitted in this figure. The control network for driving the AMB device is show
32、n 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 to the controller. Deviation from the bearing centre is delivered to the controller. This controller might, for example, implement a proportio
33、nal, integral and differential actions (PID) control algorithm. The controller drives the power amplifiers to supply the coil current. If the shaft moves downward, the upper electromagnetic coil is activated to lift the rotor upward by the magnetic force. Since, in this manner, the magnetic force ac
34、ts 15 kW Page1 BSISO148392:2004 upon the shaft so as to maintain the shaft at the neutral position inside the bearing, the AMB accomplishes both levitation and vibration control without mechanical contact. 3.2 Displacement Throughout this part of ISO 14839, the term “vibratory displacement” refers t
35、o 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 housing) is excluded from this part of ISO 14839. AMB equipment in rotating machines has its own displacement transducers
36、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 displacement transducers is the subject of this part of ISO 14839. Key 1A M B 2 displacement transducer 3 touch-down bearing 4 clear
37、ance Figure 1 Rotor system equipped with active magnetic bearings x(t) y(t) Page2 BSISO148392:2004 Key 1A M B 2 displacement transducer 3 power amplifier 4 controller 5 journal position signal 6 reference signal Figure 2 Layout of AMB control network Key 1c a s i n g 2s h a f t 3 displacement transd
38、ucers Figure 3 Displacement transducers of AMBs Page3 BSISO148392:2004 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 the rotor journal position including the d.c. component (eccen
39、tricity) 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 designated . The maximum displacement of the rotor from the c
40、learance 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 direction will generally overestimate the exact value with a maxim
41、um 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 procedure, the maximum value of the displacement values measured in t
42、wo 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 method of characterizing the maximum displacement . In order to av
43、oid 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 14839. For assessment in this part of ISO 14839, the axial moveme
44、nt, , 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 over the operational speed and load ranges of the machine. These
45、 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 addition, measurements may also be taken when different conditi
46、ons 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 xy x , y xy a x ,a y D max D max = max x 2 (t)+y 2 (t) D max x 2 max +y 2 max x max = x +a x y
47、 max = y +a y 40 % D max D max maxx max ,y max D max C min-radial D max C min-radial D max z C min-axial D max =z max C min-axial D max Page4 BSISO148392:2004 a) Orbit b) Vibration time history is the vibration orbit amplitude is the time is the eccentricity from the clearance centre a Time for one
48、revolution. Figure 4 Unfiltered shaft orbit and vibration time history a t Page5 BSISO148392:2004 3.3 Coil current and voltage At the time of publication of this part of ISO 14839, there are not enough data to define a criterion that guarantees the reliable operation of the electrical part of the AM
49、B system concerning the working current and voltage in the coils. These parameters are thus not put into the evaluation, but the corresponding information is stated as guidelines in Annexes A to C. 4 Evaluation criteria 4.1 General Two evaluation criteria are used to assess the journal displacement of AMBs. One criterion considers the magnitude of the observed displacement; the second considers chan
