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1、BRITISH STANDARD BS 4999-142: 1987 Incorporating Amendment No. 1 General requirements for rotating electrical machines Part 142: Specification for mechanical performance: vibration UDC 621.313-13:534.22-6 Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 30 08:37:19 GMT+00:00 2006, Uncontrolled Co
2、py, (c) BSI BS 4999-142:1987 This British Standard, having been prepared under the direction of the Power Electrical Engineering Standards Committee, was published under the authority of the Board of BSI and comes into effect on 27 February 1987 BSI 01-2000 First published as BS 4999-50 May 1972 Fir
3、st revision January 1978 Second revision as BS 4999-142 February 1987 The following BSI references relate to the work on this standard: Committee reference PEL/1 Revision announced in BSI News October 1986 ISBN 0 580 15782 2 Committees responsible for this British Standard The preparation of this Br
4、itish Standard was entrusted by the Power Electrical Engineering Standards Committee (PEL/-) to Technical Committee PEL/1, upon which the following bodies were represented: Association of Consulting Engineers Association of Electrical Machinery Trades Association of Manufacturers Allied to the Elect
5、rical and Electronic Industry (BEAMA Ltd.) Association of Supervisory and Executive Engineers British Coal Bureau of Engineer Surveyors ERA Technology Ltd. Electricity Supply Industry in England and Wales Engineer Surveyors Section of the ASTMS Engineering Equipment and Materials Users Association H
6、ealth and Safety Executive Ministry of Defence Power Generation Association (BEAMA Ltd.) Rotating Electrical Machines Association (BEAMA Ltd.) South of Scotland Electricity Board Amendments issued since publication Amd. No.Date of issueComments 6542November 1990 Indicated by a sideline in the margin
7、 Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 30 08:37:19 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4999-142:1987 BSI 01-2000i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2References1 Section 1. Machines with shaft centre heights not exceeding 400 mm 3Introdu
8、ction1 4Measurement quantity1 5Measuring equipment1 6Machine mounting1 7Conditions of measurement2 8Maximum limits of vibration severity2 Section 2. Machines with shaft centre heights exceeding 400 mm 9Limits of vibration4 Figure 1 Sensitivity-frequency characteristic for the vibration measuring sys
9、tem2 Figure 2 Recommended measuring points3 Table 1 Limits of vibration severity3 Table 2 Limits of vibration amplitude (peak to peak, in millimetres)4 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 30 08:37:19 GMT+00:00 2006, Uncontrolled Copy, (c) BSI
10、 BS 4999-142:1987 ii BSI 01-2000 Foreword This Part of BS 4999 has been prepared under the direction of the Power Electrical Engineering Standards Committee and supersedes BS 4999-50:1978, which is withdrawn. This Part has been issued to implement the decision to renumber all the Parts of BS 4999 to
11、 bring the Part numbers more into line with those of IEC Publication 34. In addition to the renumbering of the Part, the inclusion of the Part number in the point numbering system, adopted in Part 50, has been abandoned. No technical changes have been made to the text of BS 4999-50:1978. Section 1 o
12、f this Part implements the CENELEC1) Harmonization Document HD 347. It has been agreed within CENELEC that the method of balancing for rotating electrical machines up to 400 mm shaft centre height be in accordance with ISO 2373:1974 published by the International Organization for Standardization (IS
13、O) and that the recommended maximum limits of vibration severity given for guidance in the annex to that ISO standard be a requirement in national standards implementing the CENELEC Harmonization Document. The text of clauses 1, 3, 4, 5, 6 and 8 therefore reproduce the text of the ISO standard with
14、the editorial alterations necessary to align with the CENELEC Harmonization Document. Clause 7 does not align with the CENELEC Harmonization Document but specifies the key convention required by IEC 34-14. A British Standard does not purport to include all the necessary provisions of a contract. Use
15、rs of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 4, an inside back cover and a
16、 back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) European Committee for Electrotechnical Standardization. Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 30 08:37
17、:19 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4999-142:1987 BSI 01-20001 1 Scope Section 1 applies to 3-phase a.c. and d.c. machines with shaft centre heights between 80 mm and 400 mm and specifies the test and measurement conditions and limits for the level of vibration severity which enable th
18、e quality of a machine to be estimated as far as vibration is concerned. It does not apply to machines with centre heights below 80 mm, or to motor convertors, single-phase machines or 3-phase machines operated on single-phase systems, although it is recommended that this method of test should be us
19、ed for these machines and, where necessary, special vibration limits should be agreed between purchaser and manufacturer. Section 2 specifies the limits of vibration applicable to rotating electrical machinery with shaft centre height exceeding 400 mm. 2 References The titles of the publications ref
20、erred to in this standard are listed on the inside back cover. Section 1. Machines with shaft centre heights not exceeding 400 mm 3 Introduction Vibrations in rotating electrical machinery are caused by: unbalance in the rotating masses; slight deformations in the frame or bed of the machine caused
21、by certain magnetic attraction between the stator and rotor; the rolling bearings; aerodynamic loads and some secondary effects such as instability of the shaft in the bearings, passive resistance, asymmetric expansion, etc. In spite of the accurate balancing that can be obtained with dynamic balanc
22、ing machines, residual unbalance generally proves to be the main cause of once-per-revolution vibrations found in a machine. The measurement of vibration is closely linked with the mounting of the machine and it is usually desirable to carry out vibration measurements under actual installation and o
23、perating conditions. However, to estimate the quality as far as balance and vibrations of rotating electrical machines are concerned, it is necessary to measure on the machine alone under properly determined test conditions which permit reproducible tests to be carried out and provide comparable mea
24、surements. 4 Measurement quantity The criterion adopted for vibration severity is the r.m.s. value of the vibration velocity in millimetres per second. The greatest value, determined at the prescribed measuring points (see 7.3) characterizes the vibration severity of the machine. 5 Measuring equipme
25、nt NOTERequirements for suitable instruments are given in BS 4675-2. The equipment to be used shall have an electrical instrument with a true r.m.s. rectification characteristic, permitting reading of the r.m.s. value of vibration velocity. The instrument system shall have a frequency range from 10
26、Hz to 1 000 Hz with an overall frequency characteristic conforming to Figure 1 and a measuring accuracy not worse than 10 % of the indicated value. The transverse sensitivity of the vibration pick-up shall be less than 10 % of the sensitivity in the normal measuring direction. NOTEThere are certain
27、instruments, operating mainly on mechanical principles: for measuring the vibration displacement; for measuring the vibration acceleration; which also enable the vibration severity of the machine to be estimated. However, correspondence between vibration displacement, acceleration and velocity can b
28、e precisely determined only in the case of sinusoidal vibration. To eliminate differences in estimation and to permit effective and sufficiently accurate comparison of measurement, the only instruments to be used should be those conforming to the specifications in this clause. 6 Machine mounting To
29、ensure reproducible tests and comparable measurements, the machine shall be installed in a state of “free suspension”. This condition is achieved by suspending the machine on a spring or by mounting on an elastic support (springs, rubber, etc.) The natural oscillation frequency of the suspension sys
30、tem and machine, in the six possible degrees of freedom, shall be lower than a quarter of the frequency corresponding to the slowest rotational speed of the machine under test. The effective mass of the elastic support shall be not greater than 1/10 of that of the motor, to reduce the influence of t
31、he mass and the moments of inertia of these parts on the vibration level. Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 30 08:37:19 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4999-142:1987 2 BSI 01-2000 7 Conditions of measurement 7.1 Key. The end of the shaft shall have a half-key of norma
32、l shape and length unless otherwise specified. The key shall be the same as that used for balancing the rotor in all cases. 7.2 Vibration pick-up.Care shall be taken to ensure that the contact between the pick-up and the machine surface is as specified by the manufacturer of the pick-up and does not
33、 disturb the vibratory condition of the machine under test. The most important point is to ensure that the pressure and mass of the pick-up have no significant influence on the vibratory state of the machine. In all cases, the total coupled mass of the pick-up assembly shall be less than 1/50 of the
34、 mass of the machine. 7.3 Measuring points. Measurements shall be made on the bearings, in the neighbourhood of the shaft, in three perpendicular directions, the machine operating only in the position it occupies under normal conditions (shaft horizontal or vertical) as indicated in Figure 2. 7.4 Op
35、erating conditions. Motors shall be fed at rated voltage and nominal frequency (for alternating current) and vibration measurement shall be carried out at nominal speed. For machines with several speeds or variable speed, the test shall be carried out at the various operational speeds. In the absenc
36、e of instructions to the contrary, measurement of the vibration severity shall be carried out under no-load operation at the temperature reached by the machine after a sufficient period of no-load operation. 8 Maximum limits of vibration severity The limits of vibration severity, expressed in millim
37、etres per second, for the various standard shaft heights and for three quality grades, which are called “N” (normal), “R” (reduced) and “S” (special), shall be in accordance with Table 1. Provided that no other agreements are made, the recommended limits of quality grade “N” apply to normal electric
38、al machines. NOTE 1The manufacturer and the purchaser shall take into account that measured values can have a deviation from the true values of 10 %. Figure 1 Sensitivity-frequency characteristic for the vibration measuring system Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 30 08:37:19 GMT+0
39、0:00 2006, Uncontrolled Copy, (c) BSI BS 4999-142:1987 BSI 01-20003 NOTE 2For machines requiring better quality grades than those given in the table, these grades should be related to grade “S” by dividing grade “S” limits by 1.6 or a multiple. Because of their special nature, the arrangements to be
40、 made for installing machines of this quality grade should be the subject of prior agreement between manufacturer and user. NOTE 3A machine which is well balanced in itself and of a quality conforming with the table, may exhibit large vibrations in normal service arising from various causes such as
41、unsuitable foundations, reaction of the driven machine, etc. Vibration may also be caused by driving elements with a natural oscillation frequency very close to that due to the small residual unbalance of the rotating mass of the machine. In such cases, checking should be carried out not only on the
42、 machine, but also on each element of the installation. Table 1 Limits of vibration severity Quality gradeSpeed Maximum r.m.s. values of the vibration velocity, in mm/s for the shaft height, H, in mm 80 u H u 132132 600 u 3 600 1.82.84.5 (normal) R600 u 1 8000.711.121.8 (reduced) 1 800 u 3 6001.121.
43、82.8 S600 u 1 8000.450.711.12 (special) 1 800 u 3 6000.711.121.8 Figure 2 Recommended measuring points Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 30 08:37:19 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4999-142:1987 4 BSI 01-2000 Section 2. Machines with shaft centre heights exceeding 400
44、 mm 9 Limits of vibration The radial vibration measured on the bearings of horizontal machines in both the vertical and lateral directions under the conditions of test specified in BS 4999-143 shall not exceed the limits specified in column 1 of Table 2, but amplitudes of vibration in the axial dire
45、ction may be significantly higher than those specified in the table. Machines other than horizontal foot machines may generally have higher levels of vibration. Where the actual test speed is not tabulated, interpolation is permitted. When high precision balancing is required the limiting amplitudes
46、 of vibration and the test conditions should be agreed between the manufacturer and the purchaser at the time of enquiry and confirmed before the order is placed. A machine conforming to the limits specified in column 1 of Table 2, when tested at the manufacturers works, may exhibit greater vibratio
47、n when erected on site, depending on the balance of the apparatus to which the machine is coupled and on the stiffness of the foundations or supporting structures. Because of these factors higher vibration limits are permissible on site, but the values specified in column 2 of Table 2 should not be
48、exceeded. If the measured vibration on site is greater than the limiting values specified in column 2, attempts should be made to improve the balance of the coupled equipment. If this does not succeed in reducing the electrical machine vibration to within the specified limits, it may be necessary to
49、 stiffen the foundations or supporting structure. Table 2 Limits of vibration amplitude (peak to peak, in millimetres) Speed Column 1 Column 2 Speed Column 1 Column 2 r/minr/min 3 600 0.0200.0251 100 0.0510.064 3 400 0.0210.0271 000 0.0550.069 3 200 0.0220.028900 0.0590.074 3 000 0.0240.030850 0.0610.076 2 800 0.0250.032800 0.0630.078 2 600 0.0270.034750 0.0650.081 2 400 0.0290.036700 0.0680.085 2 200 0.0310.039650 0.0710.089 2 000 0.0330.042600 0.0740.092 1 800 0.0360.045550 0.0770.096 1 700 0.0380.047500 0.0800.100 1 600 0.0400.050450 0.0850.105 1 500 0.