ASTM_A_348_-_A_348M_-_05_2015.pdf

Designation:A348/A348M05(Reapproved 2015)Standard Test Method forAlternating Current Magnetic Properties of Materials Usingthe Wattmeter-Ammeter-Voltmeter Method,100 to 10 000 Hzand 25-cm Epstein Frame1This standard is issued under the fixed designation A348/A348M;the number immediately following 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 the determination of the mag-netic properties of flat-rolled magnetic materials using Epsteintest specimens with double-lap joints in the 25-cm Epsteinframe.It covers determination of core loss,rms and peakexciting current,exciting power,magnetic field strength,andpermeability.This test method is commonly used to testgrain-oriented and nonoriented electrical steels but may also beused to test nickel-iron,cobalt-iron,and other flat-rolledmagnetic materials.1.2 This test method shall be used in conjunction withPractice A34/A34M and Test Method A343/A343M.1.3 Tests under this test method may be conducted witheither normal ac magnetization or with ac magnetization andsuperimposed dc bias(incremental magnetization).1.4 In general,this test method has the following limita-tions:1.4.1 FrequencyThe range of this test method normallycovers frequencies from 100 to 10 000 Hz.With properequipment,the test method may be extended above 10 000 Hz.When tests are limited to the use of power sources havingfrequencies below 100 Hz,they shall use the procedures of TestMethod A343/A343M.1.4.2 Magnetic Flux Density(may also be referred to asFlux Density)The range of magnetic flux density for this testmethod is governed by the test specimen properties and by theavailable instruments and other equipment components.Normally,for many materials,the magnetic flux density rangeis from 1 to 15 kG 0.1 to 1.5 T.1.4.3 Core Loss and Exciting PowerThese measurementsare normally limited to test conditions that do not cause a testspecimen temperature rise in excess of 50C or exceed 100W/lb 220 W/kg.1.4.4 ExcitationEither rms or peak values of excitingcurrent may be measured at any test point that does not exceedthe equipment limitations provided that the impedance of theammeter shunt is low and its insertion into the test circuit doesnot cause appreciably increased voltage waveform distortion atthe test magnetic flux density.1.4.5 Incremental PropertiesMeasurement of incrementalproperties shall be limited to combinations of ac and dcexcitations that do not cause secondary voltage waveformdistortion,as determined by the form factor method,to exceeda shift of 10%away from sine wave conditions.1.5 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 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.1.6 This standard 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 use.2.Referenced Documents2.1 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 Method 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 Oct.1,2015.Published October 2015.Originallyapproved in 1960.Last previous edition approved in 2011 as A348/A348M05(2011).DOI:10.1520/A0348_A0348M-05R15.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.Summary of Test Method3.1 A representative sample of the magnetic material is cutinto Epstein strips and then annealed or otherwise treated inaccordance with the appropriate material specification or asagreed between producer and user.The strips are weighed andloaded into the Epstein frame becoming the transformer core.The primary coil is then excited with ac voltage and current atthe fre