ASTM A1013-00

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

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 +120oC, frequencies from 10 kHz to 1 MHz, under sinusoidal flux conditions.
1.2 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.
1.2 The values and equations stated in customary (cgs-emu and inch-pound) of 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.

General Information

• Status: Historical
• Publication Date: 09-Oct-2000
• ICS: 29.100.10 - Magnetic components
• Technical Committee: A06 - Magnetic Properties
• Drafting Committee: A06.01 - Test Methods

Relations

• Replaced By: ASTM A1013-00(2005) - 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
• Effective Date: 01-Nov-2005
• Referred By: ASTM A1009-18 - Standard Specification for Soft Magnetic MnZn Ferrite Core Materials for Transformer and Inductor Applications
• Effective Date: 10-Oct-2000

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:A1013–00
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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.2 Definitions of Terms Specific to This Standard:
3.2.1 bifilar transformer—a transformer in which the turns
1.1 This test method covers the equipment, procedures, and
oftheprimaryandsecondarywindingsarewoundtogetherside
measurement of core loss of either toroidal or mated soft
by side and in the same direction. This type of winding results
magnetic core components, such as soft ferrite cores, iron
in near unity coupling, so that there is a very efficient transfer
powder cores, and so forth, over ranges of controlled ambient
of energy from primary to secondary.
temperatures typically from −20 to +120°C, frequencies from
3.2.2 core-loss density, P —core loss per unit volume in
cd
10 kHz to 1 MHz, under sinusoidal flux conditions.
3 3
mW/cm [W/m ].
1.2 This standard does not purport to address all of the
3.2.3 effective permeability—the relative permeability of a
safety concerns, if any, associated with its use. It is the
magneticcircuitincludingtheeffectofairgapsinthemagnetic
responsibility of the user of this standard to establish appro-
path length.
priate safety and health practices and determine the applica-
3.2.4 mated core set—two or more core segments as-
bility of regulatory limitations prior to use.
sembled with the magnetic flux path perpendicular to the
1.3 The values and equations stated in customary (cgs-emu
mating surface.
and inch-pound) of SI units are to be regarded separately as
standard. Within this test method, SI units are shown in
4. Significance and Use
brackets except for the sections concerning calculations where
4.1 Thistestmethodisdesignedfortestingofeithertoroidal
there are separate sections for the respective unit systems. The
or mated soft magnetic core components over a range of
values stated in each system may not be exact equivalents;
temperatures, frequencies, and flux densities.
therefore,eachsystemshallbeusedindependentlyoftheother.
4.2 The reproducibility and repeatability of this test method
Combiningvaluesfromthetwosystemsmayresultinnoncon-
are such that it is suitable for design, specification acceptance,
formance with this standard.
service evaluation, and research and development.
2. Referenced Documents
5. Apparatus
2.1 ASTM Standards:
5.1 Theapparatusshallconsistofasmanyofthecomponent
A34/A34M Practice for Sampling and Procurement Test-
2 partsasshownintheblockcircuitdiagrams(Figs.1and2)and
ing of Magnetic Materials
described as follows and in the appendix, as required to
A340 Terminology of Symbols and Definitions Relating to
2 perform the tests.
Magnetic Testing
5.2 Signal Generator—A low distortion sine wave signal
E177 Practice for Use of the Terms Precision and Bias in
generator is required. The frequency accuracy of the signal
ASTM Test Methods
generator should be within 60.1% with an output amplitude
3. Terminology range from 1-mV to 10-V p-p.
5.3 Broadband Power Amplifier, capable of amplifying the
3.1 The definitions of terms, symbols, and conversion fac-
output of the signal source by 50 dB.
tors relating to magnetic testing, used in this test method, are
5.4 Volt-Amp-Watt Meter with Current Transformer, ac-
found in Terminology A340.
coupled, broadband, power factor independent, true RMS
reading instrument. Voltage channel minimum input imped-
This test method is under the jurisdiction of ASTM Committee A06 on
ance1MV,voltagerangefrom2to100V,currentrangesfrom
MagneticPropertiesandisthedirectresponsibilityofSubcommitteeA06.01onTest
5 mA to 5A, power ranges from 100 mW to 500 W. The
Methods.
full-scaleaccuracyofthewattmetershallnotexceed0.75%of
Current edition approved Oct. 10, 2000. Published January 2001.
the product of the input voltage and current ranges.
Annual Book of ASTM Standards, Vol 03.04.
Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
A1013
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)
5.5 Flux Voltmeter—A full-wave true-averaging voltmeter 6.2 When testing for material properties, the cross-sectional
with scale reading in average volts times 1.111 so that its
areaofthetestcorecomponentshallbeuniformthroughoutits
indications will be identical with those of a true rms voltmeter
entire magnetic path length. The core may be of any shape.
onapuresinusoidalvoltage.Inputimpedanceofatleast2MV.
Shapes with nonuniform cross-sectional areas within their
To produce the estimated precision of test under this test
magnetic path length can be tested for specific core shape
method, the full-scale meter errors shall not exceed 0.25%.
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.
6.3 Mated core set assembled around a prewound coil can
5.7 Temperature with Platinum RTD or Type T Thermo-
be used, as well as toroidal cores.
couple.
6.3.1 Mating surfaces must be ground smooth and flat to
5.8 Optional—Personal computer with appropriate I/O to
minimize air gaps. Air gaps cause reluctance in the flux path
control equipment and collect data.
and cause flux to fringe, both of which contribute to higher
measured losses.
6. Test Core Component
6.3.2 Clamping pressure for the mated core set needs to be
6.1 The test core component can be of any magnetic
sufficienttoholdthecorestogetherwithminimumairgapsbut
material (soft ferrite, iron powder, and so forth). The effective
not so strong that it affects the properties of the material
permeability of the material must be sufficiently high so that
through the creation of stress-magnetostriction anisotropy. A
the test core component can be driven to the desired flux
pressure of 5 lb/in. [35 kPa] is recommended where the area
density with the available test equipment (within the power
amplifier limitations). is the area of the mating surfaces.
A1013
C
6.4 The length of test leads from the measuring instruments
Effectivecorecross2sectionalarea, A 5 cm (4)
e
C
tothetestcorecomponentshouldbeminimized.Thetestleads 2
should be twisted pairs to minimize magnetic pickup. The test
lead capacitance can be significant at high frequencies and
~C !
Effectivecorevolume, V 5 cm (5)
e 2
contributes to inaccuracy in the measurements.
~C !
8.2 Calculate flux voltage as follows:
7. Procedure
7.1 Prepare the test core component in the form of a
E 5 2 pBA N f 310 (6)
=
f e 2
transformer by applying windings to a toroid or for a mated
wh
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