1、Designation: A 1013 00 (Reapproved 2005)Standard Test Method forHigh-Frequency (10 kHz-1 MHz) Core Loss of Soft MagneticCore Components at Controlled Temperatures Using theVoltmeter-Ammeter-Wattmeter Method1This standard is issued under the fixed designation A 1013; the number immediately following
2、the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method cove
3、rs the equipment, procedures, andmeasurement of core loss of either toroidal or mated softmagnetic core components, such as soft ferrite cores, ironpowder cores, and so forth, over ranges of controlled ambienttemperatures typically from 20 to +120C, frequencies from10 kHz to 1 MHz, under sinusoidal
4、flux conditions.1.2 The values and equations stated in customary (cgs-emuand inch-pound) of SI units are to be regarded separately asstandard. Within this test method, SI units are shown inbrackets except for the sections concerning calculations wherethere are separate sections for the respective un
5、it systems. Thevalues stated in each system may not be exact equivalents;therefore, each system shall be used independently of the other.Combining values from the two systems may result in noncon-formance with this standard.1.3 This standard does not purport to address all of thesafety concerns, if
6、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:2A 34/A 34M Practice for Sampling and Procurement
7、 Test-ing of Magnetic MaterialsA 340 Terminology of Symbols and Definitions Relating toMagnetic TestingE 177 Practice for Use of the Terms Precision and Bias inASTM Test Methods3. Terminology3.1 The definitions of terms, symbols, and conversion fac-tors relating to magnetic testing, used in this tes
8、t method, arefound in Terminology A 340.3.2 Definitions of Terms Specific to This Standard:3.2.1 bifilar transformera transformer in which the turnsof the primary and secondary windings are wound together sideby side and in the same direction. This type of winding resultsin near unity coupling, so t
9、hat there is a very efficient transferof energy from primary to secondary.3.2.2 core-loss density, Pcdcore loss per unit volume inmW/cm3W/m3.3.2.3 effective permeabilitythe relative permeability of amagnetic circuit including the effect of air gaps in the magneticpath length.3.2.4 mated core settwo
10、or more core segments as-sembled with the magnetic flux path perpendicular to themating surface.4. Significance and Use4.1 This test method is designed for testing of either toroidalor mated soft magnetic core components over a range oftemperatures, frequencies, and flux densities.4.2 The reproducib
11、ility and repeatability of this test methodare such that it is suitable for design, specification acceptance,service evaluation, and research and development.5. Apparatus5.1 The apparatus shall consist of as many of the componentparts as shown in the block circuit diagrams (Figs. 1 and 2) anddescrib
12、ed as follows and in the appendix, as required toperform the tests.5.2 Signal GeneratorA low distortion sine wave signalgenerator is required. The frequency accuracy of the signalgenerator should be within 60.1 % with an output amplituderange from 1-mV to 10-V p-p.5.3 Broadband Power Amplifier, capa
13、ble of amplifying theoutput of the signal source by 50 dB.1This test method is under the jurisdiction of ASTM Committee A06 onMagnetic Properties and is the direct responsibility of SubcommitteeA06.01 on TestMethods.Current edition approved Nov. 1, 2005. Published November 2005. Originallyapproved i
14、n 2000. Last previous edition approved in 2000 as A 1013 00.2For 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.1
15、Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.4 Volt-Amp-Watt Meter with Current Transformer, ac-coupled, broadband, power factor independent, true RMSreading instrument. Voltage channel minimum input imped-ance 1 MV, voltage rang
16、e from 2 to 100 V, current ranges from5 mA to 5A, power ranges from 100 mW to 500 W. Thefull-scale accuracy of the wattmeter shall not exceed 0.75 % ofthe product of the input voltage and current ranges.5.5 Flux VoltmeterA full-wave true-averaging voltmeterwith scale reading in average volts times 1
17、.111 so that itsindications will be identical with those of a true rms voltmeteron a pure sinusoidal voltage. Input impedance of at least 2 MV.To produce the estimated precision of test under this testmethod, the full-scale meter errors shall not exceed 0.25 %.5.6 Temperature Chamber, heated with el
18、ectric elements,cooled by injecting liquid CO2or liquid nitrogen into the airstream through an expansion nozzle or equivalent methods.5.7 Temperature with Platinum RTD or Type T Thermo-couple.5.8 OptionalPersonal computer with appropriate I/O tocontrol equipment and collect data.6. Test Core Compone
19、nt6.1 The test core component can be of any magneticmaterial (soft ferrite, iron powder, and so forth). The effectivepermeability of the material must be sufficiently high so thatthe test core component can be driven to the desired fluxdensity with the available test equipment (within the powerampli
20、fier limitations).6.2 When testing for material properties, the cross-sectionalarea of the test core component shall be uniform throughout itsentire magnetic path length. The core may be of any shape.Shapes with nonuniform cross-sectional areas within theirmagnetic path length can be tested for spec
21、ific core shapeperformance comparisons; however, the core-loss density willnot be accurate, since the flux density and core loss varythroughout the magnetic path length and are not uniform.FIG. 1 Basic Circuit for VAW Meter Method Using Primary and Secondary WindingsFIG. 2 Optional Circuit for VAW M
22、eter Method Using One Winding Only (See 7.1)A 1013 00 (2005)26.3 Mated core set assembled around a prewound coil canbe used, as well as toroidal cores.6.3.1 Mating surfaces must be ground smooth and flat tominimize air gaps. Air gaps cause reluctance in the flux pathand cause flux to fringe, both of
23、 which contribute to highermeasured losses.6.3.2 Clamping pressure for the mated core set needs to besufficient to hold the cores together with minimum air gaps butnot so strong that it affects the properties of the materialthrough the creation of stress-magnetostriction anisotropy. Apressure of 5 l
24、b/in.235 kPa is recommended where the area isthe area of the mating surfaces.6.4 The length of test leads from the measuring instrumentsto the test core component should be minimized. The test leadsshould be twisted pairs to minimize magnetic pickup. The testlead capacitance can be significant at hi
25、gh frequencies andcontributes to inaccuracy in the measurements.7. Procedure7.1 Prepare the test core component in the form of atransformer by applying windings to a toroid or for a matedcore set by winding a bobbin and then assembling the magneticcores around it. In either case, the winding should
26、be singlelayer, wound as a bifilar transformer, and distributed evenlyaround the winding length. The number of turns is based on themaximum voltage available from the power amplifier calcu-lated using Eq 6. If sufficient wire size (600 circular mil/amp0.30 mm2/amp) is used, the winding losses are ne
27、gligible;therefore, the secondary of Fig. 1 may be eliminated. Voltagescan then be measured across the primary as shown in theoptional circuit diagram (Fig. 2).7.2 Place the test core component in the temperature cham-ber and attach it to the test equipment.7.3 Set the chamber temperature. Sense the
28、 temperature ofthe core material by imbedding a platinum RTD or Type Tthermocouple into a block of material similar to the materialunder test and with a cross-sectional area equal to or larger thanthe test core component. Some materials, such as ferrite, arepoor thermal conductors and therefore may
29、take considerabletime to reach the ambient temperature (20 min for a 0.5- by0.5-in. 12.7- by 12.7-mm cross-sectional area is common).7.4 Use Eq 6 to calculate the flux voltage for the desired fluxdensity. Set the signal generator to the desired frequency thenadjust the output so that the flux voltme
30、ter indicates the valueof voltage calculated to give the desired test induction. Thevoltage waveform must be sinusoidal to ensure that the powermeasurements are accurate. The simplest way to verify that thevoltage waveform is sinusoidal is to observe that the fluxvoltmeter and the RMS voltmeter indi
31、cate equal values within61 %, showing that the form factor of the voltage is 1.111.7.5 For core loss determinations, read and record the powerfrom the wattmeter. Core loss density can be calculated usingEq 7.8. Calculation (Customary Units)8.1 The effective dimensional core parameters of the testspe
32、cimen are computed by normalizing the core area (A)throughout the cores magnetic path length (l). Core constantsC1and C2are calculated and used to calculate effectivemagnetic path length (l1), effective core cross-sectional area(Ae), and effective core volume (Ve), as follows:Core constant, C15(1n1n
33、Ancm21(1)Core constant, C25(1n1nAn2cm23(2)Effective magnetic path length, l15C1!2C2cm (3)Effective core cross2sectional area, Ae5C1C2cm2(4)Effective core volume, Ve5C1!3C2!2cm3(5)8.2 Calculate flux voltage as follows:Ef5 =2 p BAeN2f 3 1028(6)where:Ef= flux voltage induced in winding N2,V;B = peak fl
34、ux density, G;Ae= effective cross-sectional area of the test core compo-nent, cm2;N2= number of turns of secondary winding; andf = frequency, Hz.8.3 Calculate specific core loss density as follows:Pcd5PCVe(7)where:Pcd= core loss density, mW/cm3;PC= core loss, mW; andVe= effective core volume, cm3.9.
35、 Calculation (SI Units)9.1 The effective dimensional core parameters of the testcore component are computed by normalizing the core area (A)throughout the cores magnetic path length (l). Core constantsC1and C2are calculated and used to calculate effectivemagnetic path length (l1), effective core cro
36、ss-sectional area(Ae), and effective core volume (Ve), as follows:Core constant, C15(1n1nAnm21(8)Core constant, C25(1nlnAn2m23(9)Effective magnetic path length, l15C1!2C2m (10)Effective core cross2sectional area, Ae5C1C2m2(11)Effective core volume, Ve5C1!3C2!2m3(12)A 1013 00 (2005)39.2 Calculate flu
37、x voltage as follows:Ef5 =2 p BAeN2f (13)where:Ef= flux voltage induced in winding N2,V;B = peak flux density, T;Ae= effective cross-sectional area of the test core compo-nent, m2;N2= number of turns of secondary winding; andf = frequency, Hz.9.3 Calculate specific core loss density as follows:Pcd5
38、fPCVe(14)where:Pcd= core-loss density, W/m3;PC= core loss, W; andVe= effective core volume, m3.10. Report10.1 Report the following information:10.1.1 Core component identification,10.1.2 Test frequencies,10.1.3 Test magnetic flux densities,10.1.4 Test temperature, and10.1.5 Test results (core loss d
39、ensity).11. Precision and Bias11.1 Test ProgramNine independent laboratories per-formed core-loss measurements on a common MnZn ferritetoroid using this test method. The core loss was measured at aninduction of 1 kG 0.1 T, a frequency of 25 kHz, and at 25C.This data plus an experiment to determine r
40、epeatability at onelaboratory were used to develop the following precisioninformation.11.2 PrecisionThe precision is as follows:Core Loss, W Percent of ValueAverage test value: 0.246 . . .95 % repeatability limit (withinlaboratory)0.008 3.2595 % reproducibility limit(between laboratories)0.055 22.4T
41、he preceding terms (repeatability and reproducibility) areused as specified in Practice E 177.These values are used forthe comparison of two test results, both of which are singlemeasurements. The respective standard deviations among testresults may be obtained by dividing the preceding values by2.8
42、.11.3 BiasSince there is no accepted reference material,method, or laboratory suitable for measuring the magneticproperties determined using this test method, there is nostatement of bias.12. Keywords12.1 alternating current; core; core loss; core test; ferritecore; high frequency; magnetic material
43、; magnetic test; sinu-soidal; soft ferrite; volt-amp-wattAPPENDIX(Nonmandatory Information)X1. EQUIPMENT LIST FOR APPARATUS SHOWN IN FIGS. 1 AND 2X1.1 The following equipment list for the apparatus shownin Figs. 1 and 2 is included for information only and does notimply an endorsement of the particu
44、lar equipment manufactur-ers nor limit the use of comparable equipment.X1.1.1 Signal GeneratorHP 3225B or equivalent.X1.1.2 Broadband Power AmplifierENI 2100Lor equiva-lent.X1.1.3 Volt-Amp-Watt Meter with Current TransformerClarke-Hess Model 258 or equivalent.X1.1.4 Flux VoltmeterFluke 8810A with ac
45、 converteroption 008 or equivalent.X1.1.5 Temperature ChamberDelta Design Model 9064or equivalent.X1.1.6 Temperature Meter with Platinum RTD or Type TThermocoupleNewport 269 digital pyrometer or equivalent.X1.1.7 OptionalPersonal computer with appropriate I/Oto control equipment and collect data.AST
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47、tirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsa
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49、on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).A 1013 00 (2005)4
