ASTM A343 A343M-2014 Standard Test Method for Alternating-Current Magnetic Properties of Materials at Power Frequencies Using Wattmeter-Ammeter-Voltmeter Method and 25-cm Epstein T.pdf

1、Designation: A343/A343M 03 (Reapproved 2008)A343/A343M 14Standard Test Method forAlternating-Current Magnetic Properties of Materials atPower Frequencies Using Wattmeter-Ammeter-VoltmeterMethod and 25-cm Epstein Test Frame1This standard is issued under the fixed designation A343/A343M; the number im

2、mediately 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 Th

3、is test method covers tests for the magnetic properties of basic flat-rolled magnetic materials at power frequencies (25to 400 Hz) using a 25-cm Epstein test frame and the 25-cm double-lap-jointed core. It covers the determination of core loss, rmsexciting power, rms and peak exciting current, and s

4、everal types of ac permeability and related properties of flat-rolled magneticmaterials under ac magnetization.1.2 This test method shall be used in conjunction with Practice A34/A34M.1.3 This test method2 provides a test for core loss and exciting current at moderate and high magnetic flux densitie

5、s up to 15kG 1.5 T on nonoriented electrical steels and up to 18 kG 1.8 T on grain-oriented electrical steels.1.4 The frequency range of this test method is normally that of the commercial power frequencies 50 to 60 Hz. With properinstrumentation, it is also acceptable for measurements at other freq

6、uencies from 25 to 400 Hz.1.5 This test method also provides procedures for calculating ac impedance permeability from measured values of rms excitingcurrent and for ac peak permeability from measured peak values of total exciting currents at magnetic field strengths up to about150 Oe 12 000 A/m.1.6

7、 Explanation of symbols and abbreviated definitions appear in the text of this test method. The official symbols anddefinitions are listed in Terminology A340.1.7 The values stated in either SI units or inch-pound units and equations stated in customary (cgs-emu and inch-pound) or SIunits are to be

8、regarded separately as standard. Within this standard, SI units are shown in brackets except for the sectionsconcerning calculations where there are separate sections for the respective unit systems. The values stated in each system maynot be exact equivalents; therefore, each system shall be used i

9、ndependently of the other. Combining values from the two systemsmay result in non-conformance with the standard. Within this standard, SI units are shown in brackets except in the sectionsconcerning calculations where there are separate sections for the respective unit systems.this standard.1.8 This

10、 standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.

11、1 ASTM Standards:3A34/A34M Practice for Sampling and Procurement Testing of Magnetic MaterialsA340 Terminology of Symbols and Definitions Relating to Magnetic TestingA677 Specification for Nonoriented Electrical Steel Fully Processed TypesA683 Specification for Nonoriented Electrical Steel, Semiproc

12、essed TypesA876 Specification for Flat-Rolled, Grain-Oriented, Silicon-Iron, Electrical Steel, Fully Processed Types1 This test method is under the jurisdiction of ASTM Committee A06 on Magnetic Properties and is the direct responsibility of Subcommittee A06.01 on Test Methods.Current edition approv

13、ed May 1, 2008May 1, 2014. Published June 2008May 2014. Originally approved in 1949. Last previous edition approved in 20032008 asA343/A343M-03. -03 (2008). DOI: 10.1520/A0343_A0343M-03R08.10.1520/A0343_A0343M-14.2 Burgwin, S. L., “Measurement of Core Loss and A-C Permeability with the 25-cm Epstein

14、 Frame,” Proceedings, American Society for Testing and Materials, ASTEA,Vol 41, 1941, p. 779.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document S

15、ummary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recomme

16、nds that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1A889/A889M Test

17、Method for Alternating-Current Magnetic Properties of Materials at Low Magnetic Flux Density Using theVoltmeter-Ammeter-Wattmeter-Varmeter Method and 25-cm Epstein FrameE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study to

18、Determine the Precision of a Test MethodE1338 Guide for Identification of Metals and Alloys in Computerized Material Property Databases3. Significance and Use3.1 This test method is a fundamental method for evaluating the magnetic performance of flat-rolled magnetic materials in eitheras-sheared or

19、stress-relief annealed condition.3.2 This test method is suitable for design, specification acceptance, service evaluation, and research and development.4. Test Specimens4.1 The specimens for this test shall be selected and prepared for testing in accordance with provisions of Practice A34/A34Mand a

20、s directed in AppendixAnnex A3 of this test method.5. Basic Circuit5.1 Fig. 1 shows the essential apparatus and basic circuit connections for this test method. Terminals 1 and 2 are connected toa source of adjustable ac voltage of sinusoidal waveform and sufficient power rating to energize the prima

21、ry circuit withoutappreciable voltage drop in the source impedance.All primary circuit switches and all primary wiring should be capable of carryingmuch higher currents than are normally encountered to limit primary circuit resistance to values that will not cause appreciabledistortion of the flux w

22、aveform in the specimen when relatively nonsinusoidal currents are drawn. The ac source may be anelectronic amplifier which has a sine-wave oscillator connected to its input and may include the necessary circuitry to maintaina sinusoidal flux waveform by using negative feedback of the induced second

23、ary voltage. In this case, higher primary resistancecan be tolerated since this system will maintain sinusoidal flux at much higher primary resistance. Although the current drain inthe secondary is quite small, especially when using modern high-input impedance instrumentation, the switches and wirin

24、g shouldbe selected to minimize the lead resistance so that the voltage available at the terminals of the instruments is imperceptibly lowerthan the voltage at the secondary terminals of the Epstein test frame.6. Apparatus6.1 The apparatus shall consist of as many of the following component parts as

25、 are required to perform the desired measurementfunctions:6.2 Epstein Test Frame:FIG. 1 Basic Circuit for Wattmeter-Ammeter-Voltmeter MethodA343/A343M 1426.2.1 The test frame shall consist of four solenoids (each having two windings) surrounding the four sides of the squaremagnetic circuit, and a mu

26、tual inductor to compensate for air flux within the solenoids. The solenoids shall be wound onnonmagnetic, nonconducting forms of rectangular cross section appropriate to the specimen mass to be used. The solenoids shallbe mounted so as to be accurately in the same horizontal plane, and with the cen

27、ter line of solenoids on opposite sides of the square,250 6 0.3 mm apart. The compensating mutual inductor may be located in the center of the space enclosed by the four solenoidsif the axis of the inductor is made to be perpendicular to the plane of the solenoid windings.6.2.2 The inner or potentia

28、l winding on each solenoid shall consist of one fourth of the total number of secondary turns evenlywound in one layer over a winding length of 191 mm or longer of each solenoid. The potential windings of the four solenoids shallbe connected in series so their voltages will add. The outer or magneti

29、zing winding likewise shall consist of one fourth of the totalnumber of primary turns evenly wound over the winding length of each solenoid. These individual solenoid windings, too, shallbe connected in series so their magnetic field strengths will add. The primary winding may comprise up to three l

30、ayers using twoor more wires in parallel.6.2.3 Primary and secondary turns shall be wound in the same direction, with the starting end of each winding being at the samecorner junction of one of the four solenoids. This enables the potential between adjacent primary and secondary turns to be aminimum

31、 throughout the length of the winding, thereby reducing errors as a result of electrostatic phenomena.6.2.4 The solenoid windings on the test frame may be any number of turns suited to the instrumentation, mass of specimen, andtest frequency. Windings with a total of 700 turns are recommended for te

32、sts in the frequency range of 25 through 400 Hz.6.2.5 The mutual inductance of the air-flux compensating inductor shall be adjusted to be the same as that between thetest-frame windings to within one turn of the compensator secondary. Its windings shall be connected in series with thecorresponding t

33、est-frame windings so that the voltage induced in the secondary winding of the inductor by the primary current willcompletely oppose or cancel the total voltage induced in the secondary winding of the test frame when no sample is in place inthe solenoids. Specifications for the approximate turns and

34、 construction details of the compensating mutual inductor for thestandard test frame are given in Table A1.1 of Annex A1.6.3 Flux Voltmeter, VfA full-wave true-average, voltmeter, with scale reading in average volts times =2 pi/4 so that itsindications will be identical with those of a true rms volt

35、meter on a pure sinusoidal voltage, shall be provided for evaluating thepeak value of the test magnetic flux density. To produce the estimated precision of test under this test method, the full-scale metererrors shall not exceed 0.25 % (Note 1). Meters of 0.5 % of more error may be used at reduced a

36、ccuracy. Either digital or analogflux voltmeters are permitted. The normally high-input impedance of digital flux voltmeters is desirable to minimize loading effectsand to reduce the magnitude of instrument loss compensations. The input resistance of an analog flux voltmeter shall not be lessthan 10

37、00 /V of full-scale indication. A resistive voltage divider, a standard-ratio transformer, or other variable scaling devicemay be used to cause the flux voltmeter to indicate directly in units of magnetic flux density if the combination of basic instrumentand scaling device conforms to the specifica

38、tions stated above.NOTE 1Inaccuracies in setting the test voltage produce errors approximately two times as large in the specific core loss. Voltage scales should be suchthat the instrument is not used at less than half scale. Care should also be taken to avoid errors caused by temperature and frequ

39、ency effects in theinstrument.6.3.1 If used with a mutual inductor as a peak ammeter at magnetic flux densities well above the knee of the magnetizationcurve, the flux voltmeter must be capable of accurately measuring the extremely nonsinusoidal (peaked) voltage that is inducedin the secondary windi

40、ng of the mutual inductor. Additionally, if so used, an analog flux voltmeter should have a minimum inputresistance of 5000 /V of full-scale indication.6.4 RMS Voltmeter, VrmsA true rms-indicating voltmeter shall be provided for evaluating the form factor of the voltageinduced in the secondary windi

41、ng of the test fixture and for evaluating the instrument losses. The accuracy of the rms voltmetershall be the same as that specified for the flux voltmeter. Either digital or analog rms voltmeters are permitted. The normallyhigh-input impedance of digital rms voltmeters is desirable to minimize loa

42、ding effects and to reduce the magnitude of instrumentloss compensations. The input resistance of an analog rms voltmeter shall not be less than 5000 /V of full-scale indication.6.5 Wattmeter, WThe full-scale accuracy of the wattmeter must not be poorer than 0.25 % at the frequency of test and at un

43、itypower factor. The power factor encountered by a wattmeter during a core loss test on a specimen is always less than unity and,at magnetic flux densities far above the knee of the magnetization curve, approaches zero. The wattmeter must maintain adequateaccuracy (1.0 % of reading) even at the most

44、 severe (lowest) power factor that is presented to it. Variable scaling devices may beused to cause the wattmeter to indicate directly in units of specific core loss if the combination of basic instrument and scalingdevices conforms to the specifications stated here.6.5.1 Electronic Digital Wattmete

45、rElectronic digital wattmeters have been developed that have proven satisfactory for useunder the provisions of this test method. Usage of a suitable electronic digital wattmeter is permitted as an alternative to anelectrodynamometer wattmeter in this test method. An electronic digital wattmeter oft

46、entimes is preferred in this test methodbecause of its digital readout and its capability for direct interfacing with electronic data acquisition systems.6.5.1.1 The voltage input circuitry of the electronic digital wattmeter must have an input impedance sufficiently high thatconnection of the circu

47、itry, during testing, to the secondary winding of the test fixture does not change the terminal voltage of thesecondary by more than 0.05 %. In addition, the voltage input circuitry must be capable of accepting the maximum peak voltagethat is induced in the secondary winding during testing.A343/A343

48、M 1436.5.1.2 The current input circuitry of the electronic digital wattmeter must have an input impedance of no more than 1 .Preferably the input impedance should be no more than 0.1 if the flux waveform distortion otherwise tends to be excessive. Inaddition, the current input circuitry must be capa

49、ble of accepting the maximum rms current and the maximum peak current drawnby the primary winding of the test fixture when core loss tests are being performed. In particular, since the primary current willbe very nonsinusoidal (peaked) if core-loss tests are performed on a specimen at magnetic flux densities above the knee of themagnetization curve, the crest factor capability of the current input circuitry should be three or more.6.5.2 Electrodynamometer WattmeterAreflecting-type dynamometer is recommended among this class of instruments, but, ifthe specimen mas