1、STD-BSI BS EN L0252-ENGL L777pm lb24669 b21040 BRITISH STANDARD Magnetic materials - Methods of measurement of magnetic properties of magnetic steel sheet and strip at medium frequencies * v) * The European Standard EN 10252 : 1997 has the status of a British Standard ICs 77.140.40 BS EN 10252 : 199
2、7 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BS EN 10262 : 1997 Committees responsible for this British Standard The prepamlion of this British Standard was entrusted to Technical Committee ISE/NFE/5, Magnetic alloys and steels, upon which the following bodies were repres
3、entd Association of Manufacturem Allied to the El-cal and Electronic British Steel Industry Depariment of We and Industry (National Physical Laboratory) Electricity Supply Industry in England and Wales GAMBICA (BEL4M.A Ltd.) institute of Physics Rotating Electrical Machines Association (BEAMA Ltd.)
4、Sunderland Polytechnic (Magnet Centre) Ti.ansmission and Distribution Association (BEAMA Ltd.) Woifson Centre for Magnetics Technology Co-opted members Industry (BEAMA Ltd.) This British Standard, having been prepared under the direction of the Engineering Sector Board, was published under the auhor
5、ity of the Standards Board and comes inta effect on 15 June 1997 O BSI 1997 Amendments issued since publication I Text affected kd. No. Date The foiiowing BSI references relate to the work on this standard Commiaee reference ISE/NFEY5 Draft for cornent 86B5473 DC ISBN O 680 27618 X STD-BSI BS EN 102
6、52-ENGL 1777 1b24bb7 Ob2LULI2 bb8 = BS EN 10262 : 1997 Contents Committees responsible page Inside hnt cover Nationai foreword ii Foreword 2 Text of EN 10252 3 * * CJ-2 i STD-SI BS EN 10252-ENGL 2777 1b2qbb7 Ob21OLi3 5Tq BS EN 10262 : 1997 National foreword This British Standard has been prepared by
7、 Technid Committee ISJWFE and is the Engish language veision of EN 10252 : 1997 Magnetic materials - Methods of measurement of magnetic pmperties of magnetic steel sheet and strip at medium jhqwmks published by the European committee for Standarchation (CEN). It supemedes BS 6404 : Part 10 : 1989 wh
8、ich is withdrawn. NOTE. international and European Standards, as well as overseas standards, are available !?om Customer Services, BSI, 389 Chiswick High Road, London W4 4AL. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document
9、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. ii O BSI 1997 STD-BSI BS EN 10252-ENGL 1777 1b24bb7 Ob21O44 Y30 W EUROPEIN sTANDAII;D EN 10252 NORME EUR0PEE”E EUROP- NORM Januxy 1997 _ ICs 29.040.10; 77.140.60 D
10、escriptors: Metal plates, strips, steels, magnetic alloys, measurements, magnetic propees English version Magnetic materials - Methods of measurement of magnetic properties of magnetic steel sheet and strip at medium fkquencies Matriaux magntiques - Mhodes de mesure des Magnetkche Werkstoffe - Verfa
11、hren zur Messung pmpritranslaton under the responsibility of a CEN member into its own language and notified to the Centsal Secretariat has the same status as the official versions. CEN members are the nationai standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland,
12、 Ireland, Italy, Luxembourg, Netherlands, Norway, Portugd, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Stanh-on Comit Europen de Normalisation Europaisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels O 1997 Copyright reserved to CEN membe
13、rs Ref. No. EN 10252 : 1997 E Page 2 EN 10252 : 1997 Foreword This European Standard has been prepared by Technical Committee ECISWT 24, Electrical steel and strip quaiities - Quaiities, dimensions, tolerances and specific tests, the secretariat of which is held by AFNOR. This European standard is t
14、echnically in accordance with EC - determination of specific total losses by the wattmeter method; - determination of magnetic field strength excitation and current and specific apparent power. NOTE. The informative annex A gives the calculation method for the supplemenary loss arising from the use
15、of the Epstein frame at meium frequencies. 2 Normative references Ihis European Standard incorporates by dated or undated reference, provisions fiom other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafkr. For dated refe
16、rences, 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. IEC 50 (221) International EktmteehnicaL Vocabulu (Im),
17、Chapter 221: Magneth 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; therefore, it is not always possible to state the absolute accuracy whic
18、h cm be attained. Moreover, experience in the use of a given method indicates the reproducibility which can be expected. Whenever the drafting Technicai Committee has agreed upon reproducibility values, these have been given in this standard. 4 General conditions for a.c. measurements made with the
19、25 em Epstein frame 4.1 Scope This clause specifies the general conditions for the determination of ac. magnetic properties of electricai steel sheet and strip by means of the 25 cm Epstein frame. Page 3 EN lu252 : 1997 The use of the 25 cm Epstein frame is applicable to flat stsip specimens obtaine
20、d hm electrical sheets and stsips of any quality. The magnetic properties are determined for a sinusoidal induced voltage. The measurements are made at an ambient temperature of 23 “C f 6 “C on test specimens which have first been demagnetized. 4.2 Principle of the 26 cm Epstein frame method The 25
21、cm Epstein frame, which comprises a primary winding, a secondary win- and the specimen to be tested as a core, forms an unloaded transformer whose properties are measured by the methods described in the following clauses. At the higher end of the frequency range a speciaily constructed Epstein frame
22、 (see annex A) may be required in which the interwinding capacitances are low and the materiai of the winding formets supporting the solenoids has a low dielechic loss. A sep- measuring system (for example a commercially available universal bridge capable of measuring resistance, capacitance and ind
23、uctance) is required to detennine the interwjnding capacitance of the Epstein frame. 4.3 Test specimens The magnetic circuit shall be made up of a core constnicted with the strips to be tested, assembled in a square having doublelapped joints (see figure 1) to form four branches of equal length and
24、equal cross-sectional area I Figure 1. Double-lapped joints 1 The ships shail be sampled in accordance with the product standard. They shall be cut by a method which will produce clean burr-free edges. They shail have the foliowing dimensions: -widthb =IWL+_O,IIUII; - length I such tsiat28omm 5 I 55
25、00 mm, the 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
26、 as the reference direction. O BSI 1997 STD-BSI BS EN 10252-ENGL 1997 W 1b24bb ObZLDLi7 1,T-m Page 4 EN 10252 : 1997 The foiowing tolerances shall be allowed for the angle between the diredion of rolling and that of cutting: Il“ for grain-oriented steel sheec k 5 for non-oriented steel sheet. nly fi
27、at strips shall be used Measurements shall be made without additional insulation. The number of strips forming a test specimen shall be not less than tweve and shall be a multiple of four. A force of 1 N f 0,l N shall be applied to each corner, nod to the piane of the overlapping strips. 4.4 26 cm E
28、pstein frame The 25 cm Epstein fixme (hereafter referred to as the E - 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 windin
29、gs of the four solenoids shall be connected in series, and the secondary individual windings sha be COM m = mass of test specimen, in kiiogrammes; d, = conventional effective magnetic path length, in me- 2 = length of a test specimen strip, in metres. 4.6 Air flux compensation A correction for air f
30、lux shall be made for field = strengths greater than or equal to lo00 Ahn. For low frequencies (iess than or equal to loo0 Hz) a mutual inductor may be used to compensate for the air flux, The mutual inductance of the compensator shall be dusted to be the same as that of the windings of the empty pr
31、operly connected, 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 me by the flux attributed to the primary current. E * Ln * frame. Thus when the windings are Page 6 EN 10252
32、: 1997 4.6 Power supply The source shall be of low internai impecance and shall be highly stable in terms of voltage and frequency During the measurement, the Variation of voltage and the variation of frequency shall not exceed i 0,2 % of the specified value. The form factor of the secondary induced
33、 voltage shall be maintaineci within k 1 % of 1,111 (this can be achieved by various means, e.g. electronic feedback amplifien). 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. voitmeter, such as a movi
34、ng iron instrum ent and the latter by an average type voltmeter, such as a rectifier-type instnxment. NOTE. When a negative feedback amplifier is used for the suppiy it may be necessary to observe the waveform of the secondary induced voltage on an osciioscope to ensure that the waveform of the fund
35、amental frequency is being produced. 6 Determination of specific total loss by the wattmeter method 6.1 Scope This clause describes the wattmeter method for the determination of the specific tota loss of electrical steel sheet strip at frequencies in the range 400 Hz to1oOooHz. The specific total lo
36、ss is determined, according to this method, for specified peak values of magnetic polarization and for a specified frequency. in order to obtain comparable resdts, test values shal be referred to magnetic polarization of sinusoidal waveform. NOTE. Throughout this standard the term magnetic polarizat
37、ion is used as defined in Chapter 221, IEC 50. in some publications the term magnetic flux density has been used. 6.2 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 show
38、n in figure 3 which illustmtes the principle. P I i I 3 4 measures average rectified voltage measures r.m.s. voltage = mutual inductor = Epstein frame L Figure 3. Circuit for the wattmeter method O BSI 1997 STD-BSI BS EN 10252-ENGL 1777 1b24bb7 Ob2L047 TL2 W Page 6 EN 10252 : 1997 5.3 Apparatus 5.3.
39、1 Voltage measurement 6.3.1.1 Average tw volmter The average value of the secondary rectifed voltage of the Epstein frame shall be measured with an average type voltmeter of ammcy 0,5 % or better (e.g. a or - measuring the voltage drop across a non-inductive precision resistor connected in series wi
40、th the primary winding. The combined uncertainties of the resistor and the voltmeter shall not exceed 1 Oh The ammeter and the precision rr, respectively, shall be shortcircuited when the secondary voltage is adjusted and the losses are measured. 5.3.3 Frequency measurement A frequency meter of accu
41、racy 0,2 % or better shall be used. 6.3.4 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. The resistance of the voltag
42、e circuit of the wattmeter shall be greater than or equal to 1OWV for ali ranges. :f necessary the losses in the secondary circuit shall be subtracted Grom the indicated loss value. Moreover, the ohmic resistance of the voltage circuit shall be at least5OOOhes the reactance, unless the wattmeter is
43、compensahi for the latter, to avoid corrections of phase angle. where IGI = f= fkequency in hertz; combined equivaient resistance of the secondary windings of Epstein frame and mutual inductor, in OW, series resistance of the secondary windings of Epstein frame and mutual inductor, in Ohms, number o
44、f turns of the secondary winding; crosfsection of test specimen, in square me-, peak vaiue of magnetic polarization, in teslas. The crosssection A is obained by the equation (3) . where: m = mass of test specimen, in kiiogmmmes; 1 = length of a test specimen strip, in metres; pm = density of the tes
45、t material, in kilogrammes per cubic metre. 6.4.3 Measurements The ammeter in the primary circuit shdl be observed to ensure that the current circuit of the wattmeter is not overloaded. Then the ammeter shall be short-circuited and the secondary voltage readjusted After checking the waveform of the
46、secondary voltage in compliance with 4.6, the wattmeter shall be read. NOTE. To avoid undue heating of the test specimen and to facilitate reproducibility, measurements should be made as quickly as possible after energizing the Epstein frame. The specimen should be aiiowed to cool between readings.
47、0 BSI 1997 STD-BSI BS EN L0252-ENGL 1997 = lb24bb9 Ob21050 734 = Page 7 EN 10252 : 1997 6.6 Determination of specific total loss The power P, measured by the wattmeter includes the power consumed by the instnim ents in the secondary circuit, which to a first approximation is equa to (i,ii1lGly/q sin
48、ce the secondary voltage is essentially sinkoida. Thus, the totai loss Pc of the test specimen shall be calculated from the equation: where: 1 pc pIn Ni N2 4 = calculated total loss of test specimen, in = power measured by the wathneter, in = number of tunis of the primary winding; = number of turns
49、 of the secondary = combined equivalent resistance of the Watts; watts; winding; instruments in the secondary circuit, in Ohms, - tU,t = average due of secondam rectified - L* = - voltage, in volts. = The specic total loss P, shall be obtained by dividing Pc by the effective mass of the test specimen, see 4.4. = - - - where: P, = specific total loss of test specimen, in watts per Wogramme (corrected if necessary) for flux waveform distortion according to 4.6 m = mass of test specimen, in kiiogrammeq ma = effective mass of test specimen, in
