1、DEUTSCHE NORM Mav 1997 DIN EN 10252 Magnetic materials Methods of measurement of magnetic properties of magnetic steel sheet and strip at medium frequencies English version of DIN EN 10252 ICs 29.030: 77.140.50 Descriptors: Steel, magnetic steel, testing. Magnetische Werkstoffe - Verfahren zur Messu
2、ng der magnetischen Eigenschaften von Elektroblech und -band bei mittleren Frequenzen European Standard EN 10252: 1997 has the status of a DIN Standard. A comma is used as the decimal marker. National foreword This standard has been prepared by ECISS/TC 24. The responsible German body involved in it
3、s preparation was the Deutsche Elektrotechnische Kommission im DIN und VDE (German Electrotechnical Commission of DIN and VDE), Technical Committee Verfahren zur Bestimmung der Eigenschaften magnetischer Werkstoffe. This standard is based on IEC 404-10. National Annex NA Standard referred to (and no
4、t included in Normative references) IEC 404-10 Magnetic materials - Part 10: Methods of measurement of magnetic properties of magnetic steel sheet and strip at medium frequencies EN comprises 23 pages. Q No pari of this standard may be reproduced without the prior permission of DIN Deutsches Institu
5、t fr Normung e.V., Berlin. Beuth Verlag GmbH, Berlin, has the exclusive right of sale for German Standards (DIN-Normen). Ref. No. DIN EN 10252: 1997-05 Sales No. 1108 01.98 English price group 08 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 10252 January 1997 ICs 29.040.10; 77.140.50 Descrip
6、tors: Steel, magnetic steel, testing English version Magnetic materials Methods of measurement of magnetic properties of magnetic steel sheet and strip at medium frequencies Matriaux magntiques - Mthodes de mesure des proprits magntiques frquences moyennes des tles et feuil- lards magntiques en acie
7、r Magnetische Werkstoffe - Verfahren zur Messung der magnetischen Eigenschaf- ten 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 the CENLENELEC Internal Regulations which stipulate the conditions for
8、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 or to any CEN member. The European Standards exist in three official ve
9、rsions (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 versions. CEN members are the national standards bodies of Austria, Belgium
10、, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, and the United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de St
11、assart 36, B-IO50 Brussels O 1997. CEN - All rights of exploitation in any form and by any means reserved worldwide for CEN national members. Ref. No. EN 10252:1997 E Page 2 EN 10252 : 1997 Contents Page Foreword 1 Scope 2 Normative references 3 Accuracy and reproducibility 3 4 General conditions fo
12、r a.c. measurements made with the 25 cm Epstein frame 4 5 Determination of specific total loss by the wattmeter method 9 6 Determination of magnetic field strength, excitation current and specific apparent power 14 Annexes 23 A (informative) Epstein frame for use at medium frequencies 23 Foreword Th
13、is European Standard has been prepared by Technical Committee ECISS/TC 24 “Electrical steel and strip qualitiees - 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 editoria
14、l amendments. This European Standard 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 CENKENELEC Internal Regu
15、lations, the national standards 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.
16、Page 3 EN 10252 : 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 O00 Hz. This European Standard specifies the following methods for the measurement of magnetic properties of e
17、lectrical 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 nd specific apparent power. NOTE. The informative annex A gives the calculation
18、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. These normative references are cited at the appropriate places in the text
19、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 undated references the latest edition of the publication referred to applies.
20、 IEC 50 (22 1) 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 other features of the measuring environment and equipment components; there
21、fore, 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 Committee has agreed upon reproducibility values, these have been given in this
22、 standard. Page 4 EN 10252 : 1997 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 strip by means of the 25 cm Epstein frame. The use of
23、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 23 “C - length I such that 280 mm I I s 500 mm, the
24、 strips being of the same length within a tolerance of f 0,5 mm. For specimens of length greater than 305 mm, care shall be taken to avoid bending the strips during the 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 re
25、ference direction. The following tolerances shall be allowed for the angle between the direction of rolling and that of cutting: f 1“ for grain-oriented steel sheet; f 5“ for non-oriented steel sheet; Only flat strips shall be used. Measurements shall be made without additional insulation. The numbe
26、r of strips forming a test specimen shall be not less than twelve and shall be a multiple of four. A force of 1 N f 0,l N shall be applied to each corner, normal to the plane of the overlapping strips. - Page 6 EN 10252 : 1997 4.4 25 cm Epstein frame The 25 cm Epstein frame (hereafter referred to as
27、 the “Epstein frame“) shall consist of four solenoids which are practically identical into which the test specimen strips are introduced in such a manner that a closed magnetic circuit is formed (see figure 2). lrn = 0,94 in Figure 2: 25 cm Epstein frame If measurements are to be made under the cond
28、itions 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 dielectric loss, such as polystyrene, and have a rectangular cross-section and an inner width of 32 mm. A height of ab
29、out 5 mm will be sufficient and is recommended. Page 7 EN 10252 : 1997 The solenoids shall be mounted on a non-conducting and non-magnetic base plate in a square arrangement. Each side of the inner square formed by the test specimen strips shall have a length of 220 i mm (figure 2). In order to avoi
30、d 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 solenoid comprises two windings: - a primary winding (magnetizing winding): - a secondary wind
31、ing (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 windings of the four solenoids shall be connected in series, and the secondary individual win
32、dings 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 significant. The windings shall be spaced to minimize this loss. The capacitance between the
33、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 shall be chosen to suit the particular conditions of the power supply, instrumentation and meas
34、uring frequency. A total of 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 O00 Hz. The impedance of the windings shall be sufficiently small to avoid waveform distortion and minimize internal voltage drops. T
35、he effective length 1, of the magnetic path in this test equipment is conventionally taken as 0,94 m. This value shall be used. Page 8 EN 10252 : 1997 Consequently, the effective mass, i.e. the magnetically active mass of the test specimen, is given by the equation: .m m, - - 41 - 1, where : ma = ef
36、fective mass of test specimen, in kilogrammes rn = mass of test specimen, in kilogrammes 1, = conventional effective magnetic path length, in metres 1 = 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 eq
37、ual to 1000 A/m. For low frequencies (less 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 connect
38、ed, the voltage induced in the secondary winding 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 sha
39、ll be highly stable in terms of voltage and frequency. During the measurement, the variation of voltage and the variation of frequency shall not exceed f 0,2 % of the specified value. The form factor of the secondary induced voltage shall be maintained within * 1 96 of 1.111 (this can be achieved by
40、 various means, e.g. electronic feedback amplifiers). 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. volmeter, such as a moving iron instrument and the latter by an average type voltmeter, such as a re
41、ctifier-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 produced. Page 9 EN 10252 : 1997 5 Determination
42、of specific total loss by the wattmeter method 5.1 Scope This clause describes the wattmeter method for the determination of the specific total loss of electrical steel sheet strip at frequencies in the range 400 Hz to 10 O00 Hz. The specific total loss is determined, according to this method, for s
43、pecified peak values of magnetic polarization and for a specified frequency. In order to obtain comparable results, test values shall be referred to magnetic polarization of sinusoidal waveform. NOTE. Throughout this standard the term “magnetic polarization“ is used as defined in Chapter 221, IEC 50
44、. In some publications the term “magnetic flux density“ has been used. 5.2 Principle of measurement The 25 cm Epstein frame with the test specimen represents an unloaded transformer whose total losses are measured by the wattmeter method in the circuit shown in figure 3 which illustrates the princip
45、le. v1 v2 Mc E measures average rectified voltage measures r.m.s. voltage mutual inductor Epstein frame Figure 3. Circuit for the wattmeter method Page 10 EN 10252 : 1997 5.3 Apparatus 5.3.1 Voltage measurement 5.3.1.1 Average type voltmeter The average value of the secondary rectified voltage of th
46、e Epstein frame shall be measured with an average type voltmeter of accuracy 0,5 % or better (e.g. a rectifier type digital voltmeter). NOTE. Instruments of this type are usually graduated in average rectified value multiplied by 1,111. The load on the secondary circuit of the network shall be as sm
47、all as possible. Consequently, the internal resistance of the average type voltmeter shall be at least 1000 Q/V. 5.3.1.2 R. M. S voltmeter A voltmeter of accuracy 0,5 % or better shall be used, e.g. a r.m.s. sensing digital voltmeter. 5.3.2 Current measurement The primary current may be measured by
48、either: - a class 1 ammeter or better of low impedance; or - measuring the voltage drop across a non-inductive precision resistor connected in series with the primary winding. The combined uncertainties of the resistor and the voltmeter shall not exceed 1 %. The ammeter and the precision resistor, r
49、espectively, shall be short-circuited when the secondary voltage is adjusted and the losses are measured. 5.3.3 Frequency measurement A frequency meter of accuracy 0.2 % or better shall be used. 5.3.4 Power measurement The power shall be measured by a wattmeter of accuracy 0,5 % or better at the frequency, power factor, and crest factor to be used. Readings in the first quarter of the scale shall be avoided as far as possible. Page 11 EN 10252 : 1997 The resistance of the voltage circuit of the wattmeter shall be greater than or equal to 100 WV for all ranges. If necessary
