1、BRITISH STANDARD BS 5944-2: 1992 ISO 4412-2: 1991 Measurement of airborne noise from hydraulic fluid power systems and components Part 2: Method of test for motorsBS5944-2:1992 This British Standard, having been prepared under the directionof the Machinery and Components Standards Policy Committee,
2、was published underthe authority of the Standards Board and comes intoeffect on 15December1992 BSI 02-2000 First published November 1980 Second edition December 1992 The following BSI references relate to the work on this standard: Committee reference MCE/18 Draft for comment 89/78172 DC ISBN 0 580
3、21396 X Committees responsible for this BritishStandard The preparation of this British Standard was entrusted by the Machinery and Components Standards Policy Committee (MCE/-) to Technical Committee MCE/18, upon which the following bodies were represented: Advanced Manufacturing Technology Researc
4、h Institute Association of British Mining Equipment Companies Bath University British Compressed Air Society British Fluid Power Association British Steel Industry Department of Trade and Industry (National Engineering Laboratory) Ministry of Defence The following bodies were also represented in the
5、 drafting of the standard, through subcommittees and panels: British Hydromechanics Research Association British Railways Board Society of Motor Manufacturers and Traders Ltd. Amendments issued since publication Amd. No. Date CommentsBS5944-2:1992 BSI 02-2000 i Contents Page Committees responsible I
6、nside front cover National foreword ii Introduction 1 1 Scope 1 2 Normative references 1 3 Definitions 1 4 Measurement uncertainty 2 5 Test environment 2 6 Instrumentation 2 7 Installation conditions 2 8 Operating conditions 3 9 Location and number of sound measurement points 3 10 Test procedure 3 1
7、1 Information to be recorded 4 12 Test report 5 13 Identification statement (Reference to this part of ISO 4412) 5 Annex A (normative) Calculation of sound levels 6 Annex B (normative) Errors and classes of measurement 6 Annex C (informative) Guidelines for the application of this part of ISO 4412 6
8、 Annex D (informative) Bibliography 16 Figure C.1 Transmission paths of sound energy from motors 7 Figure C.2 Instrumentation for manual data logging 8 Figure C.3 Multiple microphone scanning instrumentation 9 Figure C.4 Corrections for background noise 10 Figure C.5 Motor noise test configuration w
9、ith hemispherical measuring array 11 Figure C.6 Mounting and driveline arrangement for hemispherical measurement 11 Figure C.7 “Minimized” motor mount (two-bolt flange mounting configuration) 13 Figure C.8 Diagrammatic view of the hemispherical layout showing fluid line cladding 14 Figure C.9 Exampl
10、e of test circuit 16 Table 1 Standard deviation of sound power level determinations 2 Table 2 Allowable variations of mean indicated values of controlled parameters 3 Table B.1 Permissible systematic errors of measuring instruments as determined during calibration 6 List of references Inside back co
11、verBS5944-2:1992 ii BSI 02-2000 National foreword This Part of BS5944 has been prepared under the direction of the Machinery and Components Standards Policy Committee. It is identical with ISO4412-2:1991 Hydraulic fluid power Test code for determination of airborne noise levels Part2: Motors, publis
12、hed by the International Organization for Standardization (ISO). On publication of BS5944-1:1992 and BS5944-2:1992, the1980 editions of BS5944-1, BS5944-2 and BS5944-3 will be withdrawn. BS5944 comprises the following Parts. Part 1: Method of test for pumps; Part 2: Method of test for motors; Part 3
13、: Withdrawn; Part 4: Method of determining sound power levels from valves controlling flow and pressure; Part 5: Simplified method of determining sound power levels from pumps using an anechoic chamber; Part 6: Method of test for pumps using parallelepiped microphone array. For the purposes of the B
14、ritish Standard the identification statement required by clause13 may be replaced by the following: “Airborne noise levels determined in accordance with BS5944-2” Cross-references International Standard Corresponding British Standard ISO3019-2:1986 BS6276:1987 Specification for dimensions and identi
15、fication code for mounting flanges and shaft ends for hydraulic fluid power pumps and motors (Technically equivalent) ISO3488:1975 BS4231:1982 Classification for viscosity grades of industrial liquid lubricants (Identical) BS4196 Sound power levels of noise sources ISO3744:1981 Part4:1981 Engineerin
16、g methods for determination of sound power levels for sources in free-field conditions over a reflecting plane (Identical) ISO3745:1977 Part5:1981 Precision methods for determination of sound power levels for sources in anechoic and semi-anechoic rooms (Identical) ISO6743-4:1982 BS6413 Lubricants, i
17、ndustrial oils and related products (Class L) Part4:1983 Classification for family H (hydraulicsystems) (Identical) IEC50(801):1984 BS4727 Glossary of electrotechnical, power, telecommunication, electronics, lighting, and colour terms Part3: Group08:1985 Acoustics and electroacoustics terminology (T
18、echnically equivalent) IEC651:1979 BS5969:1981 Specification for sound level meters (Identical)BS5944-2:1992 BSI 02-2000 iii The Technical Committee has reviewed the provisions of ISO2204:1979 and ISO5598:1985 to which reference is made in the text and has decided that they are acceptable for use in
19、 conjunction with this standard. There are no corresponding British Standards for ISO2204 or ISO5598. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standar
20、d does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi toiv, pages1 to16, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. T
21、his will be indicated in the amendment table on the inside front cover.iv blankBS5944-2:1992 BSI 02-2000 1 Introduction In hydraulic fluid power systems, power is transmitted and controlled through a liquid under pressure in an enclosed circuit. Motors are components which convert rotary fluid power
22、 to mechanical power. During the process of converting hydraulic fluid power to mechanical power, airborne noise, fluid-borne vibrations and structure-borne vibrations are radiated from the motor. The airborne noise level of a hydraulic fluid power motor is an important consideration in component se
23、lection. The noise measurement technique must, therefore, be such as to yield accurate appraisals of these airborne noise levels. The determination of noise levels is complicated by the interactions which occur during noise measurements. The fluid-borne vibrations from the motor can be transmitted t
24、o the circuit and ultimately give rise to background airborne noise levels which could affect the determination of the motor airborne noise levels. The procedures described in this part of ISO4412 are intended to measure only the airborne noise radiated directly from the motor under test. 1 Scope Th
25、is part of ISO4412 establishes a test code describing procedures, based on ISO2204, for the determination of the sound power levels of a hydraulic fluid power motor, under controlled conditions of installation and operation, suitable for providing a basis for comparing the noise levels of motors in
26、terms of: A-weighted sound power level; octave band sound power levels. From these sound power levels, if required, reference sound pressure levels may be calculated for reporting purposes in accordance withAnnex A. For general purposes, the frequency range of interest includes the octave bands with
27、 centre frequencies between125Hz and8000 Hz. 1) Due to the inherent difficulties in the measurement of low-speed motor performance, this part of ISO4412 is limited to motors operating at speeds exceeding50r/min. Guidelines for the application of this part of ISO4412 are given inAnnex C. This part of
28、 ISO4412 is applicable to all types of hydraulic fluid power motors operating under steady-state conditions, irrespective of size, except for any limitations imposed by the size of the test environment (see clause5). 2 Normative references The following standards contain provisions which, through re
29、ference in this text, constitute provisions of this part of ISO4412. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO4412 are encouraged to investigate the possibility of applying the most recent
30、 editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 3448:1975, Industrial liquid lubricants ISOviscosity classification. ISO 3744:1981, Acoustics Determination of sound power levels of noise sources Engineering methods
31、 for free-field conditions over a reflecting plane. ISO 3745:1977, Acoustics Determination of sound power levels of noise sources Precision methods for anechoic and semi-anechoic rooms. ISO 5598:1985, Fluid power systems and components Vocabulary. ISO 6743-4:1982, Lubricants, industrial oils and rel
32、ated products (class L) Classification Part4: Family H (Hydraulic systems). IEC 50(801):1984, International Electrotechnical Vocabulary Chapter801: Acoustics and electroacoustics. IEC 651:1979, Sound level meters. 3 Definitions For the purposes of this part of ISO4412, the definitions given in ISO55
33、98, IEC50 and the following definitions apply. It is accepted that the latter definitions may differ from those in other specific International Standards. 3.1 free sound field sound field in a homogeneous, isotropic medium free of boundaries NOTE 1In practice, it is a field in which the effects of t
34、he boundaries are negligible over the frequency range of interest. 3.2 free field over a reflecting plane field produced by a source in the presence of one reflecting plane on which the source is located 3.3 reverberant sound field that portion of the sound field in a test room over which the influe
35、nce of sound received directly from the source is negligible 1) 1Hz = 1 s 1BS5944-2:1992 2 BSI 02-2000 3.4 anechoic room a test room having boundaries which absorb essentially all of the incident sound energy over the frequency range of interest, thereby affording free-field conditions over the meas
36、urement surface 3.5 mean-square sound pressure the sound pressure averaged in space and time on a mean-square basis NOTE 2In practice, this is estimated by space and time averaging over a finite path length or over a number of fixed microphone positions. 3.6 mean sound pressure level ten times the l
37、ogarithm to the base10 of the ratio of the mean-square sound pressure to the square of the reference sound pressure, in decibels (dB) NOTE 3The weighting network or the width of the frequency band used should always be indicated; for example, A-weighted sound pressure level, octave band sound pressu
38、re level. The reference sound pressure is204Pa 2) . 3.7 sound power level ten times the logarithm to the base10 of the ratio of a given sound power to the reference sound power, in decibels NOTE 4The weighting network or the width of the frequency band used should always be indicated. The reference
39、sound power is1pW 3) . 3.8 volume of source under test volume of the envelope of the whole motor under test 4 Measurement uncertainty Methods of measurement should be used which tend to result in standard deviations which are equal to or less than those specified inTable 1. Methods given in ISO3744
40、meet this requirement. Table 1 Standard deviation of sound power leveldeterminations The standard deviations given inTable 1 include the effects of allowable variations in the positioning of the measurement points and in the selection of any prescribed measurement surface, but exclude variations in
41、the sound power output of the source from test to test. NOTE 5The A-weighted sound power level will in most practical cases be determined with a standard deviation of approximately2dB. 5 Test environment Tests shall be conducted in an environment which provides “free-field over a reflecting plane” o
42、r “special reverberant” conditions which meet the environmental qualification requirements described in ISO3744:1981, clause 4 and Annex A. For more precise measurements, conduct tests in accordance with ISO3745. 6 Instrumentation 6.1 The instrumentation used to measure fluid flow, fluid pressure, m
43、otor speed and fluid temperature shall be in accordance with the recommendations for “industrial class” accuracy of testing; i.e. class C given inAnnex B. 6.2 The instrumentation used for acoustical measurements shall be in accordance with IEC651. This instrumentation shall be in accordance with ISO
44、3744 for both performance and calibration; i.e.type2 instruments for engineering (grade2) measurements. 7 Installation conditions 7.1 Motor location The motor may be located in any position consistent with the source installation and measurement surface (or microphone traverse) requirements specifie
45、d in ISO3744 for the test environment being used. 7.2 Motor mounting 7.2.1 The motor mounting shall be constructed so that it will minimize the noise radiated by the mounting as a result of motor vibrations. 7.2.2 The mounting bracket shall be constructed of high-damping material or with sound-dampi
46、ng and sound-insulating material applied to the bracket as required. 7.2.3 Vibration isolation techniques, if needed, shall be used even if the motor is usually securely mounted. 2) 14Pa = 10 6 N/m 2 3) 1pW = 10 12 W Standard deviation, dB, for octave bands centred on: 125 Hz 250 Hz 500 Hz 1 000 Hz
47、to 4 000 Hz 8 000 Hz 5,0 3,0 2,0 2,0 3,0BS5944-2:1992 BSI 02-2000 3 7.2.4 Flange mountings that are as small as practical shall be used so as to minimize interference with radiation of sound towards the shaft end of the motor. 7.3 Motor-driven load The load system shall be located outside the test s
48、pace and the load shall be driven through flexible couplings and an intermediate shaft, or the load system shall be isolated in an acoustic enclosure. 7.4 Hydraulic circuit 7.4.1 The circuit shall include all oil filters, oil coolers, reservoirs and restrictor valves as required to meet the motor hy
49、draulic operating conditions (see clause8). 7.4.2 The test fluid and degree of filtration shall be in accordance with the motor manufacturers recommendations. 7.4.3 Inlet and discharge lines shall be installed with diameters in accordance with the manufacturers recommended practice. 7.4.4 The outlet pressure gauge shall be mounted at the same height as the outlet fittings or it shall be calibrated for any height difference. 7.4.5 Pressure fluctuations and standing waves in the inlet and outlet ports shall be m
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