1、Designation:A889/A889M14Standard Test Method forAlternating-Current Magnetic Properties of Materials at LowMagnetic Flux Density Using the Voltmeter-Ammeter-Wattmeter-Varmeter Method and 25-cm Epstein Frame1This standard is issued under the fixed designation A889/A889M;the number immediately followi
2、ng the designation indicates the yearof original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers t
3、ests for the magnetic propertiesof basic flat-rolled magnetic materials at power frequencies(25to 400 Hz)using a 25-cm Epstein test frame and the 25-cmdouble-lap-jointed core.1.2 The magnetic properties of materials are determinedfrom measurements on Epstein core specimens with the coreand test coil
4、s treated as though they constituted a series-parallelequivalent circuit(Fig.A1.1)for the fundamental frequency ofexcitation where the apparent parallel inductance,L1,andresistance,R1,are attributable to the test specimen.1.3 This test method is suitable for the determination of coreloss,rms volt-am
5、peres,rms exciting current,reactive volt-amperes,and related properties of flat-rolled magnetic materi-als under ac magnetization.1.4 The frequency range of this test method is normally thatof the commercial power frequencies 50 to 60 Hz.It is alsoacceptable for measurements at frequencies from 25 t
6、o 400 Hz.This test method is customarily used on nonoriented electricalsteels at inductions up to 10 kG 1.0 T and for grain-orientedelectrical steels at inductions up to 15 kG 1.5 T.1.5 For reactive properties,both flux and current waveformsintroduce limitations.Over its range of useful inductions,t
7、hevarmeter is valid for the measurement of reactive volt-amperes(vars)and inductance permeability.For the measurement ofthese properties,it is suggested that test inductions be limitedto values sufficiently low that the measured values of vars donot differ by more than 15%(Note 1)from those calculat
8、edfrom the measured values of exciting volt-amperes and coreloss.NOTE1This limitation is placed on this test method in considerationof the nonlinear nature of the magnetic circuit,which leads to a differencebetween vars based on fundamental frequency components of voltage andcurrent and current afte
9、r harmonic rejection and vars computed from rmscurrent,voltage,and watt values when one or more of these quantities arenonsinusoidal.1.6 This test method shall be used in conjunction withPractice A34/A34M.1.7 Explanation of terms,symbols,and definitions used maybe found in the various sections of th
10、is test method.The officiallist of definitions and symbols may be found in TerminologyA340.1.8 The values and equations stated in customary(cgs-emuand inch-pound)or SI units are to be regarded separately asstandard.Within this standard,SI units are shown in bracketsexcept for the sections concerning
11、 calculations where there areseparate sections for the respective unit systems.The valuesstated in each system may not be exact equivalents;therefore,each system shall be used independently of the other.Combin-ing values from the two systems may result in nonconformancewith this standard.1.9 This st
12、andard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to its use.2.Referenced Documents2.1
13、 ASTM Standards:2A34/A34M Practice for Sampling and Procurement Testingof Magnetic MaterialsA340 Terminology of Symbols and Definitions Relating toMagnetic TestingA343/A343M Test Method for Alternating-Current Mag-netic Properties of Materials at Power Frequencies UsingWattmeter-Ammeter-Voltmeter Me
14、thod and 25-cm Ep-stein Test Frame1This test method is under the jurisdiction of ASTM Committee A06 onMagnetic Properties and is the direct responsibility of Subcommittee A06.01 on TestMethods.Current edition approved May 1,2014.Published May 2014.Originallyapproved in 1988.Last previous edition app
15、roved in 2008 as A889/A889M-03(2008).DOI:10.1520/A0889_A0889M-14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.C
16、opyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.Significance and Use3.1 This test method may be used to determine the specificcore loss,specific reactive power,specific exciting power,inductance permeability,and impedance permeability of flat-rolled magnetic materials over a wide range of inductions andat frequencies up to 400 Hz for symmetrically magnetized testsamples.3.2 These measurements are used by the producer and userof the f