1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-18894-8 SANS 1470-3:2008Edition 2SOUTH AFRICAN NATIONAL STANDARD Sound power labelling Part 3: Rotating electrical machinery Published by
4、Standards South Africa 1 dr lategan road groenkloof private bag x191 pretoria 0001 tel: 012 428 7911 fax: 012 344 1568 international code + 27 12 www.stansa.co.za Standards South Africa SANS 1470-3:2008 Edition 2 Table of changes Change No. Date Scope Acknowledgement Standards South Africa wishes to
5、 acknowledge the valuable assistance derived from publications of the following organizations: Council of the European Communities International Organization for Standardization Foreword This South African standard was approved by National Committee StanSA TC 76, Acoustics, electro-acoustics and vib
6、ration, in accordance with procedures of Standards South Africa, in compliance with annex 3 of the WTO/TBT agreement. This document was published in April 2008. This document supersedes SABS 1470-3:1997 (edition 1.1). SANS 1470 consists of the following parts, under the general title Sound power lab
7、elling: Part 1: Compressors. Part 2: Welding generators. Part 3: Rotating electrical machinery. Part 4: Pneumatic equipment. Annex A forms an integral part of this document. SANS 1470-3:2008 Edition 2 1 Contents Page Acknowledgement Foreword 1 Scope 3 2 Normative references 3 3 Definitions 4 4 Requi
8、rements 4 4.1 Labelling 4 4.2 Noise emission 5 5 Inspection and testing . 5 5.1 Inspection 5 5.2 Test for noise emission. 5 5.3 Modifications to the test method described in SANS 3744. 5 Figures 1 to 4. 8-9 Annex A (normative) Two-surface method to determine the environmental correction K2for in-sit
9、u measurements . 10 Bibliography. 12 SANS 1470-3:2008 Edition 2 2 This page is intentionally left blank SANS 1470-3:2008 Edition 2 3 Sound power labelling Part 3: Rotating electrical machinery 1 Scope 1.1 This standard covers the requirements for the labelling of rotating electrical machinery with a
10、 noise emission value and specifies the test method to be used for the verification of the labelled value. NOTE 1 The “two-surface method“ (see A.4.3 of SANS 3744:1994) to determine the environmental correction is given in annex A. NOTE 2 This standard refers to SANS 3744 and specifies an engineerin
11、g method of measuring the sound pressure levels at prescribed microphone positions on a rectangular parallelepiped surface that envelops the rotating electrical machine under investigation. NOTE 3 For planning purposes, additional information will be required, e.g. measurements of the octave or one-
12、third octave band pressure levels. 1.2 This standard does not cover electrostatic machines. 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 latest editi
13、on of the referenced document (including any amendments) applies. Information on currently valid national and international standards can be obtained from Standards South Africa. SANS 656, Sound level meters. SANS 658, Integrating-averaging sound level meters. SANS 3744:1994/ISO 3744, Acoustics Dete
14、rmination of sound power levels of noise sources using sound pressure Engineering method in an essentially free field over a reflecting plane. SANS 60034-1/IEC 60034-1, Rotating electrical machines Part 1: Rating and performance. SANS 61672-1/IEC 61672-1, Electroacoustics Sound level meters Part 1:
15、Specifications. SANS 61672-2/IEC 61672-2, Electroacoustics Sound level meters Part 2: Pattern evaluation tests. SANS 1470-3:2008 Edition 2 4 3 Definitions For the purposes of this document, the definitions given in SANS 3744 and the following definitions apply. 3.1 A-weighted sound power level LWAth
16、e sound power level of a machine, determined in accordance with the test method specified in this standard, with frequency weighting A (see SANS 656, SANS 658, SANS 61672-1 and SANS 61672-2) selected on the measuring instruments NOTE A-weighted sound power levels are measured in decibels. 3.2 batch
17、a number of rotating electrical machines of the same performance and manufactured to the same technical specification by one manufacturer NOTE A batch may either be an entire production series or a portion thereof. 3.3 batch labelling a single labelled value (Lc) applied to a batch of rotating elect
18、rical machines 3.4 labelled value Lc an integer value, determined by the manufacturer, representing the maximum sound power level of a rotating electrical machine 3.5 near field sound field a sound field near a sound source where instantaneous sound pressure and particle velocity are substantially o
19、ut of phase 3.6 rotating electrical machine an electrical apparatus that depends on the interaction of electro-magnetic fields for its operation, that has components capable of relative rotary movement and that is intended to convert energy NOTE This term also applies to electrical apparatus that op
20、erates on the same principle, is similar in construction and is intended for other purposes, e.g. regulation. 4 Requirements 4.1 Labelling Each rotating electrical machine shall bear a label that contains at least the following information: a) the labelled value Lc; b) the letter “B“ or “I“ to indic
21、ate batch labelling or individual labelling, respectively; and SANS 1470-3:2008 Edition 2 5 c) the identification of the labelled product (i.e. rotating electrical machine or rotating electrical machine plus coupled component) by means of a serial number. NOTE 1 As an example, the labelling for a ro
22、tating electrical machine of a given power can be as follows: Labelling Interpretation (B) Lc97 23456 “(B)“ indicates that this rotating electrical machine is one of a batch that are all labelled with the same value: 97. The labelled value in accordance with this standard is 97. “23456“ is the seria
23、l number of the rotating electrical machine. NOTE 2 The labelled value may be displayed on the existing specification/information plate affixed to the rotating electrical machine. NOTE 3 For assessment purposes, e.g. the existence of tonal components, or for planning purposes, additional spectral in
24、formation for different operating conditions will be required. 4.2 Noise emission When tested in accordance with 5.2, a rotating electrical machine shall have an A-weighted sound power level LWAnot exceeding the labelled value Lc. 5 Inspection and testing 5.1 Inspection Inspect each rotating electri
25、cal machine for compliance with 4.1. 5.2 Test for noise emission NOTE The standard deviation of A-weighted sound power levels determined in accordance with this standard is approximately 2 dB for a source that emits noise without pronounced spectral deviations. Use the test method described in SANS
26、3744, modified as described in 5.3, to determine the A-weighted sound power level LWAof the rotating electrical machine, and check for compliance with 4.2. 5.3 Modifications to the test method described in SANS 3744 5.3.1 Criterion for adequacy of the test environment (see 4.1 and 4.2 of SANS 3744:1
27、994) When the test is to be carried out indoors, use one of the methods described in annex A of SANS 3744:1994 to determine the environmental correction K2. If the environmental correction K2exceeds 2 dB, the test environment is not suitable for measurements in accordance with this standard. NOTE Se
28、e NOTE 2 to 1.1. SANS 1470-3:2008 Edition 2 6 5.3.2 Criterion for background noise Determine the correction for the background noise (K1) in accordance with 8.3 of SANS 3744:1994. Averaged over the microphone positions, the level of the background noise shall be at least 6 dB, but preferably more th
29、an 15 dB, below the sound pressure level to be measured. 5.3.3 Instrumentation (see clause 5 of SANS 3744:1994) When integrating the squared signal over a fixed time-interval, use a type 1 integrating device or system that complies with the requirements of SANS 656, SANS 658, SANS 61672-1 and SANS 6
30、1672-2. 5.3.4 Installation and operation of the rotating electrical machine (see clause 6 of SANS 3744:1994) a) Machine mounting If practicable, mount the machine in the same way as it would be mounted in normal usage. Take care to minimize the transmission and the radiation of structure-borne noise
31、 from all mounting elements, including the foundation. Usually, this minimizing can be achieved by resilient mounting for small machines. Large machines can usually only be tested under rigid mounting conditions. 1) Resilient mounting. Ensure that the natural frequency of the support system and of t
32、he machine under test is lower than a quarter of the frequency corresponding to the lowest rotational speed of the machine. Ensure that the effective mass of the resilient support does not exceed one-tenth of the effective mass of the machine under test. 2) Rigid mounting. Rigidly mount the machine
33、to a surface of dimensions adequate for the machine type (for example by foot or flange fixed in accordance with the manufacturers specifications). Do not subject the machine to additional mounting stresses from incorrect shimming. NOTE The mass of the support shall be at least twice that of the mac
34、hine under test, or as specified by the manufacturer. b) Operation of machine during test 1) Conduct sound pressure level measurements after the machine has reached the operational temperature. 2) Operate the machine under no-load conditions, at rated voltage(s) and speed(s), and with the correspond
35、ing excitation(s) (see SANS 60034-1). 3) For a.c. machines, ensure that the sinusoidality of the supply voltage and the degree of unbalance of the supply voltage system comply with the same limits that are specified in SANS 60034-1. 4) Synchronous machines shall be run with the excitation current th
36、at permits the rated voltage at no load. SANS 1470-3:2008 Edition 2 7 c) Auxiliary equipment Acoustically shield the noise generated by auxiliary equipment or components that are mounted away from the main machine, e.g. loading machines, gears, transformers, external cooling systems or coupled machi
37、nes. Regard components that cannot be separated from the rotating electrical machine as an integral part of the machine and measure them as such. 5.3.5 Measurement surface and microphone positions (see 7.3 of SANS 3744:1994) a) Measurement surface. Use a rectangular parallelepiped at a constant dist
38、ance of 1 m from the reference surface. b) Key microphone positions (see figures 1 to 4). From figure 1, derive the principle of how to construct the measurement array for different sizes of reference box. Treat each side of the measurement surface separately. If the length or width of the side of t
39、he measurement surface under consideration exceeds 3d, so divide this side into a minimum number of partial areas that their lengths and widths do not exceed 3d (see figure 1). See the resulting complete measurement array as shown in figures 2 to 4 for different sizes of reference box. c) Additional
40、 microphone positions. If measurements at additional microphone positions are required, choose these positions in accordance with figure 1. d) Reduction of number of microphone positions. The nine key points may be reduced to five (numbers 1, 2, 3, 4 and 9 in figure 2) if it has been proven that the
41、 surface sound pressure level determined in this way on a similar rotating electrical machine does not deviate by more than 1,0 dB from the value determined using nine key points. NOTE The overhead microphone position may be omitted for safety purposes. 5.3.6 Measurement of the A-weighted sound pres
42、sure level (see 7.5 of SANS 3744:1994) Obtain the following data: a) the A-weighted sound pressure level during operation of the rotating electrical machine under test; and b) the A-weighted sound pressure level of the background noise, with the rotating electrical machine inoperative. 5.3.7 Calcula
43、tion of the A-weighted sound power level Calculate the A-weighted sound power level of the rotating electrical machine in accordance with clause 8 of SANS 3744:1994. SANS 1470-3:2008 Edition 2 8 Figure 1 Procedure for fixing the measurement positions where a side of the measurement surface exceeds 3
44、d Figure 2 Example of a measurement surface and measurement positions (paths) for a small machine (l1 d, l2 d, l3 2d, where d is the measurement distance, normally 1m) SANS 1470-3:2008 Edition 2 9 Figure 3 Example of a measurement surface and measurement positions (paths) for a long machine (4d l1 7
45、d, l2 d, l3 2d) Figure 4 Example of a measurement surface and measurement positions (paths) for a large machine (4d l1 7d, d l2 4d, 2d l3 5d) SANS 1470-3:2008 Edition 2 10 Annex A (normative) Two-surface method to determine the environmental correction K2for in-situ measurements A.1 General Normally
46、, the noise level of a rotating electrical machine is determined outdoors under free-field conditions or in special test rooms for which the environmental correction has been determined. Determination of the sound pressure level of rotating electrical machinery can, in some cases, only be carried ou
47、t in situ, with the result that the acoustic environment is far from ideal. The environmental correction K2which needs to be applied in such cases may be determined in accordance with the absolute comparison test or by using one of the methods based on room absorption (see annex A of SANS 3744:1994)
48、. The method given in this annex is based on the “two-surface method“ given in A.4.3 of SANS 3744:1994. A.2 Measurement surfaces and microphone locations For the qualification of the environment, use two measurement surfaces as follows: a) the first is the same surface as is used when the sound powe
49、r level of the rotating electrical machine under test is being determined and this area is designated S1; and b) the second is geometrically similar to the first one, but located further away from the rotating electrical machine under test. The area of this measurement surface is designated S2. A ratio of S2to S1, approximately equal to 4, is recommended. The microphone positions on the second measurement surface are chosen to correspond with those for the measurement surface used for the determination of the sound power level. NOTE The determination
