1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 10252 : 1997 The Eu
2、ropean Standard EN 10252 : 1997 has the status of a British Standard ICS 77.140.40 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Magnetic materials Methods of measurement of magnetic properties of magnetic steel sheet and strip at medium frequenciesBS EN 10252 : 1997 This Br
3、itish Standard, having been prepared under the direction of the Engineering Sector Board, was published under the authority of the Standards Board and comes into effect on 15 June 1997 BSI 1997 The following BSI references relate to the work on this standard: Committee reference ISE/NFE/5 Draft for
4、comment 86/35473 DC ISBN 0 580 27618 X Amendments issued since publication Amd. No. Date Text affected Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee ISE/NFE/5, Magnetic alloys and steels, upon which the following bodies
5、 were represented: Association of Manufacturers Allied to the Electrical and Electronic Industry (BEAMA Ltd.) British Steel Industry Department of Trade and Industry (National Physical Laboratory) Electricity Supply Industry in England and Wales GAMBICA (BEAMA Ltd.) Institute of Physics Rotating Ele
6、ctrical Machines Association (BEAMA Ltd.) Sunderland Polytechnic (Magnet Centre) Transmission and Distribution Association (BEAMA Ltd.) Wolfson Centre for Magnetics Technology Co-opted membersBS EN 10252 : 1997 BSI 1997 i Contents Page Committees responsible Inside front cover National foreword ii F
7、oreword 2 Text of EN 10252 3ii BSI 1997 BS EN 10252 : 1997 National foreword This British Standard has been prepared by Technical Committee ISE/NFE/5 and is the English language version of EN 10252 : 1997 Magnetic materials Methods of measurement of magnetic properties of magnetic steel sheet and st
8、rip at medium frequencies published by the European Committee for Standardization (CEN). It supersedes BS 6404 : Part 10 : 1989 which is withdrawn. NOTE. International and European Standards, as well as overseas standards, are available from Customer Services, BSI, 389 Chiswick High Road, London W4
9、4AL. 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, the EN title page, pages 2 to 12, an inside back cover and a back cover.CEN European Committee for Standar
10、dization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1997 Copyright reserved to CEN members Ref. No. EN 10252 : 1997 E EUROPEAN STANDARD EN 10252 NORME EUROPE ENNE EUROPA ISCHE NORM January 1997 ICS 29.040.10; 77.140.5
11、0 Descriptors: Metal plates, strips, steels, magnetic alloys, measurements, magnetic properties English version Magnetic materials Methods of measurement of magnetic properties of magnetic steel sheet and strip at medium frequencies Mate riaux magne tiques Me thodes de mesure des proprie te s magne
12、tiques a fre quences moyennes des to les et feuillards magne tiques en acier Magnetische Werkstoffe Verfahren zur Messung der magnetischen Eigenschaften von Elektroblech und-band bei mittleren Frequenzen This European Standard was approved by CEN on 1995-05-13. CEN members are bound to comply with t
13、he CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat
14、or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official ver
15、sions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.Page 2 EN 10252 : 1997 BSI 1997 Foreword This European Standard has b
16、een prepared by Technical Committee ECISS/TC 24, Electrical steel and strip qualities Qualities, dimensions, tolerances and specific tests, the secretariat of which is held by AFNOR. This European Standard is technically in accordance with IEC 404-10, with some editorial amendments. This European St
17、andard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by July 1997, and conflicting national standards shall be withdrawn at the latest by July 1997. According to the CEN/CENELEC Internal Regulations, the national standar
18、ds organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Contents Page Foreword 2 1 Sc
19、ope 3 2 Normative references 3 3 Accuracy and reproducibility 3 4 General conditions for a.c. measurements made with the 25 cm Epstein frame 3 5 Determination of specific total loss by the wattmeter method 5 6 Determination of magnetic field strength, excitation current and specific apparent power 7
20、 Annexes A (informative) Epstein frame for use at medium frequencies 11Page 3 EN 10252 : 1997 BSI 1997 1 Scope This European Standard is applicable to electrical steel sheet and strip for the construction of magnetic circuits for use in the frequency range 400 Hz to 10 000 Hz. This European Standard
21、 specifies the following methods for the measurement of magnetic properties of electrical steel sheet and strip: a.c. measurements made with the 25 cm Epstein frame; determination of specific total losses by the wattmeter method; determination of magnetic field strength excitation and current and sp
22、ecific apparent power. NOTE. The informative annex A gives the calculation method for the supplementary loss arising from the use of the Epstein frame at medium frequencies. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications.
23、These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For un
24、dated references the latest edition of the publication referred to applies. IEC 50 (221) International Electrotechnical Vocabulary (IEV), Chapter 221: Magnetism 3 Accuracy and reproducibility The final accuracy of the test apparatus is a complex function dependent on the measuring instruments and ot
25、her features of the measuring environment and equipment components; therefore, it is not always possible to state the absolute accuracy which can be attained. Moreover, experience in the use of a given method indicates the reproducibility which can be expected. Whenever the drafting Technical Commit
26、tee has agreed upon reproducibility values, these have been given in this standard. 4 General conditions for a.c. measurements made with the 25 cm Epstein frame 4.1 Scope This clause specifies the general conditions for the determination of a.c. magnetic properties of electrical steel sheet and stri
27、p by means of the 25 cm Epstein frame. The use of the 25 cm Epstein frame is applicable to flat strip specimens obtained from electrical sheets and strips of any quality. The magnetic properties are determined for a sinusoidal induced voltage. The measurements are made at an ambient temperature of 2
28、3 C 5 C on test specimens which have first been demagnetized. 4.2 Principle of the 25 cm Epstein frame method The 25 cm Epstein frame, which comprises a primary winding, a secondary winding and the specimen to be tested as a core, forms an unloaded transformer whose properties are measured by the me
29、thods described in the following clauses. At the higher end of the frequency range a specially constructed Epstein frame (see annex A) may be required in which the interwinding capacitances are low and the material of the winding formers supporting the solenoids has a low dielectric loss. A separate
30、 measuring system (for example a commercially available universal bridge capable of measuring resistance, capacitance and inductance) is required to determine the interwinding capacitance of the Epstein frame. 4.3 Test specimens The magnetic circuit shall be made up of a core constructed with the st
31、rips to be tested, assembled in a square having double-lapped joints (see figure 1) to form four branches of equal length and equal cross-sectional area. Figure 1. Double-lapped joints The strips shall be sampled in accordance with the product standard. They shall be cut by a method which will produ
32、ce clean burr-free edges. They shall have the following dimensions: width b =3 0m m 0,2 mm; length l such that 280 mm# l # 500 mm, the strips being of the same length within a tolerance of 0,5 mm. For specimens of length greater than 305 mm, care shall be taken to avoid bending the strips during the
33、 test. When the strips are cut parallel or normal to the direction of rolling, the edge of the parent sheet shall be taken as the reference direction.Page 4 EN 10252 : 1997 BSI 1997 Figure 2. 25 cm Epstein frame The following tolerances shall be allowed for the angle between the direction of rolling
34、 and that of cutting: 1 for grain-oriented steel sheet; 5 for non-oriented steel sheet. Only flat strips shall be used. Measurements shall be made without additional insulation. The number of strips forming a test specimen shall be not less than twelve and shall be a multiple of four. A force of 1 N
35、 0,1 N shall be applied to each corner, normal to the plane of the overlapping strips. 4.4 25 cm Epstein frame The 25 cm Epstein frame (hereafter referred to as the Epstein frame) shall consist of four solenoids which are practically identical into which the test specimen strips are introduced in su
36、ch a manner that a closed magnetic circuit is formed (see figure 2). If measurements are to be made under the conditions specified in 4.5, a mutual inductor shall be provided for air flux compensation. The winding formers supporting the solenoids shall be made of hard insulating material of low diel
37、ectric loss, such as polystyrene, and have a rectangular cross-section and an inner width of 32 mm. A height of about 5 mm will be sufficient and is recommended. The solenoids shall be mounted on a non-conducting and non-magnetic base plate in a square arrangement. Each side of the inner square form
38、ed by the test specimen strips shall have a length of 220 mm 0 +1 (figure 2). In order to avoid undue wear of the winding formers and especially of their inner surfaces, winding formers of larger cross-section can be used, into which replaceable liners of appropriate dimensions may be inserted. Each
39、 solenoid comprises two windings: a primary winding (magnetizing winding); a secondary winding (voltage winding). The windings on each solenoid shall be evenly distributed over a length of at least 190 mm, with each solenoid carrying one-fourth of the total number of turns. The individual primary wi
40、ndings of the four solenoids shall be connected in series, and the secondary individual windings shall be connected in a similar fashion. At high frequencies, the loss due to the capacitance between the primary and secondary windings and also the self-capacitance of the secondary winding could be si
41、gnificant. The windings shall be spaced to minimize this loss. The capacitance between the windings and the self-capacitance of the secondary winding shall be measured. If necessary, a correction shall be applied for the loss introduced. The number of turns of the primary and secondary windings shal
42、l be chosen to suit the particular conditions of the power supply, instrumentation and measuring frequency.Page 5 EN 10252 : 1997 BSI 1997 V 1 measures average rectified voltage V 2 measures r.m.s. voltage M c = mutual inductor E = Epstein frame Figure 3. Circuit for the wattmeter method A total of
43、200 turns for each of the primary and secondary windings is recommended and is commonly used for tests in the frequency range 400 Hz to 10 000 Hz. The impedance of the windings shall be sufficiently small to avoid waveform distortion and to minimize internal voltage drops. The effective length l m o
44、f the magnetic path in this test equipment is conventionally taken as 0,94 m. This value shall be used. Consequently, the effective mass, i.e. the magnetically active mass of the test specimen, is given by the equation: m a = m (1) l m 4l where: m a = effective mass of test specimen, in kilogrammes;
45、 m = mass of test specimen, in kilogrammes; l m = conventional effective magnetic path length, in metres; l = length of a test specimen strip, in metres. 4.5 Air flux compensation A correction for air flux shall be made for field strengths greater than or equal to 1000 A/m. For low frequencies (less
46、 than or equal to 1000 Hz) a mutual inductor may be used to compensate for the air flux. The mutual inductance of the compensator shall be adjusted to be the same as that of the windings of the empty Epstein frame. Thus when the windings are properly connected, the voltage induced in the secondary w
47、inding of the mutual inductor by the primary current compensates for the voltage induced in the secondary winding of the empty Epstein frame by the flux attributed to the primary current. 4.6 Power supply The source shall be of low internal impedance and shall be highly stable in terms of voltage an
48、d frequency. During the measurement, the variation of voltage and the variation of frequency shall not exceed 0,2 % of the specified value. The form factor of the secondary induced voltage shall be maintained within 1% of 1,111 (this can be achieved by various means, e.g. electronic feedback amplifi
49、ers). The form factor of the secondary voltage is the quotient of the r.m.s. value and the average rectified value. The former is measured by an r.m.s. voltmeter, such as a moving iron instrument and the latter by an average type voltmeter, such as a rectifier-type instrument. NOTE. When a negative feedback amplifier is used for the supply it may be necessary to observe the waveform of the secondary induced voltage on an oscilloscope to ensure that the waveform of the fundamental frequency is being pr
