ASTM A1013-00(2013)e1
(Test Method)Standard Test Method for High-Frequency (10 kHz-1 MHz) Core Loss of Soft Magnetic Core Components at Controlled Temperatures Using the Voltmeter-Ammeter-Wattmeter Method
Standard Test Method for High-Frequency (10 kHz-1 MHz) Core Loss of Soft Magnetic Core Components at Controlled Temperatures Using the Voltmeter-Ammeter-Wattmeter Method
SIGNIFICANCE AND USE
4.1 This test method is designed for testing of either toroidal or mated soft magnetic core components over a range of temperatures, frequencies, and flux densities.
4.2 The reproducibility and repeatability of this test method are such that it is suitable for design, specification acceptance, service evaluation, and research and development.
SCOPE
1.1 This test method covers the equipment, procedures, and measurement of core loss of either toroidal or mated soft magnetic core components, such as soft ferrite cores, iron powder cores, and so forth, over ranges of controlled ambient temperatures typically from −20 to +120°C, frequencies from 10 kHz to 1 MHz, under sinusoidal flux conditions.
1.2 The values and equations stated in customary (cgs-emu and inch-pound) or SI units are to be regarded separately as standard. Within this test method, SI units are shown in brackets except for the sections concerning calculations where there are separate sections for the respective unit systems. The values 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 nonconformance with this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: A1013 − 00 (Reapproved 2013)
Standard Test Method for
High-Frequency (10 kHz-1 MHz) Core Loss of Soft Magnetic
Core Components at Controlled Temperatures Using the
Voltmeter-Ammeter-Wattmeter Method
This standard is issued under the fixed designation A1013; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Language in the units statement was editorially corrected in June 2013.
1. Scope ASTM Test Methods
1.1 This test method covers the equipment, procedures, and
3. Terminology
measurement of core loss of either toroidal or mated soft
3.1 The definitions of terms, symbols, and conversion fac-
magnetic core components, such as soft ferrite cores, iron
tors relating to magnetic testing, used in this test method, are
powder cores, and so forth, over ranges of controlled ambient
found in Terminology A340.
temperatures typically from −20 to +120°C, frequencies from
10 kHz to 1 MHz, under sinusoidal flux conditions. 3.2 Definitions of Terms Specific to This Standard:
3.2.1 bifilar transformer—a transformer in which the turns
1.2 The values and equations stated in customary (cgs-emu
oftheprimaryandsecondarywindingsarewoundtogetherside
and inch-pound) or SI units are to be regarded separately as
by side and in the same direction. This type of winding results
standard. Within this test method, SI units are shown in
in near unity coupling, so that there is a very efficient transfer
brackets except for the sections concerning calculations where
of energy from primary to secondary.
there are separate sections for the respective unit systems. The
3.2.2 core-loss density, P —core loss per unit volume in
values stated in each system may not be exact equivalents;
cd
3 3
mW/cm [W⁄m ].
therefore,eachsystemshallbeusedindependentlyoftheother.
Combiningvaluesfromthetwosystemsmayresultinnoncon-
3.2.3 effective permeability—the relative permeability of a
formance with this standard.
magneticcircuitincludingtheeffectofairgapsinthemagnetic
path length.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.2.4 matedcoreset—twoormorecoresegmentsassembled
responsibility of the user of this standard to establish appro-
with the magnetic flux path perpendicular to the mating
priate safety and health practices and determine the applica-
surface.
bility of regulatory limitations prior to use.
4. Significance and Use
2. Referenced Documents
4.1 Thistestmethodisdesignedfortestingofeithertoroidal
2.1 ASTM Standards:
or mated soft magnetic core components over a range of
A34/A34MPractice for Sampling and Procurement Testing temperatures, frequencies, and flux densities.
of Magnetic Materials
4.2 The reproducibility and repeatability of this test method
A340Terminology of Symbols and Definitions Relating to
are such that it is suitable for design, specification acceptance,
Magnetic Testing
service evaluation, and research and development.
E177Practice for Use of the Terms Precision and Bias in
5. Apparatus
5.1 Theapparatusshallconsistofasmanyofthecomponent
This test method is under the jurisdiction of ASTM Committee A06 on
partsasshownintheblockcircuitdiagrams(Figs.1and2)and
MagneticPropertiesandisthedirectresponsibilityofSubcommitteeA06.01onTest
Methods.
described as follows and in the appendix, as required to
Current edition approved May 1, 2013. Published June 2013. Originally
perform the tests.
approved in 2000. Last previous edition approved in 2005 as A1013–00 (2005).
DOI:10.1520/A1013–00R13E01.
5.2 Signal Generator—A low distortion sine wave signal
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
generator is required. The frequency accuracy of the signal
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
generator should be within 60.1% with an output amplitude
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. range from 1-mV to 10-V p-p.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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A1013 − 00 (2013)
FIG. 1 Basic Circuit for VAW Meter Method Using Primary and Secondary Windings
FIG. 2 Optional Circuit for VAW Meter Method Using One Winding Only (See 7.1)
5.3 Broadband Power Amplifier, capable of amplifying the 5.8 Optional—Personal computer with appropriate I/O to
output of the signal source by 50 dB. control equipment and collect data.
5.4 Volt-Amp-Watt Meter with Current Transformer, ac-
6. Test Core Component
coupled, broadband, power factor independent, true RMS
reading instrument. Voltage channel minimum input imped-
6.1 The test core component can be of any magnetic
ance1MΩ,voltagerangefrom2to100V,currentrangesfrom
material (soft ferrite, iron powder, and so forth). The effective
5 mA to 5A, power ranges from 100 mW to 500 W. The
permeability of the material must be sufficiently high so that
full-scaleaccuracyofthewattmetershallnotexceed0.75%of
the test core component can be driven to the desired flux
the product of the input voltage and current ranges.
density with the available test equipment (within the power
amplifier limitations).
5.5 Flux Voltmeter—A full-wave true-averaging voltmeter
with scale reading in average volts times 1.111 so that its
6.2 When testing for material properties, the cross-sectional
indications will be identical with those of a true rms voltmeter
areaofthetestcorecomponentshallbeuniformthroughoutits
onapuresinusoidalvoltage.Inputimpedanceofatleast2MΩ.
entire magnetic path length. The core may be of any shape.
To produce the estimated precision of test under this test
Shapes with nonuniform cross-sectional areas within their
method, the full-scale meter errors shall not exceed 0.25%.
magnetic path length can be tested for specific core shape
performance comparisons; however, the core-loss density will
5.6 Temperature Chamber, heated with electric elements,
not be accurate, since the flux density and core loss vary
cooled by injecting liquid CO or liquid nitrogen into the air
throughout the magnetic path length and are not uniform.
stream through an expansion nozzle or equivalent methods.
5.7 Temperature with Platinum RTD or Type T Thermo- 6.3 Mated core set assembled around a prewound coil can
couple. be used, as well as toroidal cores.
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A1013 − 00 (2013)
6.3.1 Mating surfaces must be ground smooth and flat to magnetic path length (l ), effective core cross-sectional area
minimize air gaps. Air gaps cause reluctance in the flux path (A ), and effective core volume (V ), as follows:
e e
and cause flux to fringe, both of which contribute to higher
n
n
Coreconstant, C 5 cm (1)
measured losses.
(
A
1 n
6.3.2 Clamping pressure for the mated core set needs to be
n
n
sufficienttoholdthecorestogetherwithminimumairgapsbut 23
Coreconstant, C 5 cm (2)
2 (
An
not so strong that it affects the properties of the material
through the creation of stress-magnetostriction anisotropy. A C
~ !
2 Effectivemagneticpathlength, l 5 cm (3)
pressure of 5 lb/in. [35 kPa] is recommended where the area
C
is the area of the mating surfaces.
C
Effectivecorecross 2 sectionalarea, A 5 cm (4)
e
6.4 The length of test leads from the measuring instruments C
tothetestcorecomponentshouldbeminimized.Thetestleads 3
C
~ !
Effectivecorevolume, V 5 cm (5)
should be twisted
...
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