ASTM A1013-00(2020)

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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-May-2020
• ICS: 29.100.10 - Magnetic components
• Technical Committee: A06 - Magnetic Properties
• Drafting Committee: A06.01 - Test Methods

Relations

• Replaces: ASTM A1013-00(2013)e1 - 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-Jun-2020
• Refers: ASTM A340-23a - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-Dec-2023
• Refers: ASTM A340-19b - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 15-Oct-2019
• Refers: ASTM A340-19a - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 15-Jun-2019
• Refers: ASTM A340-19 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 15-Feb-2019
• Refers: ASTM A340-18 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-Jun-2018
• Refers: ASTM A340-17a - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 15-Oct-2017
• Refers: ASTM A340-17 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-Jul-2017
• Refers: ASTM A340-16e1 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-May-2016
• Refers: ASTM A340-16 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-May-2016
• Refers: ASTM A340-15 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-Oct-2015
• Refers: ASTM A340-14 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-Oct-2014
• Refers: ASTM E177-14 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2014
• Refers: ASTM E177-13 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2013
• Refers: ASTM A34/A34M-06(2012) - Standard Practice for Sampling and Procurement Testing of Magnetic Materials
• Effective Date: 01-Nov-2012

Overview

ASTM A1013-00(2020) is a standard test method developed by ASTM International for measuring the high-frequency core loss of soft magnetic core components. This method, also known as the Voltmeter-Ammeter-Wattmeter (VAW) Method, is applicable to toroidal and mated core shapes made from soft magnetic materials such as ferrite cores and iron powder cores. The standard is designed for testing magnetic core components under controlled temperatures (from -20°C to +120°C) and high-frequency ranges (10 kHz to 1 MHz) using sinusoidal flux conditions.

Accurate measurement of high-frequency core loss is important for evaluating the performance of magnetic materials used in modern electronic devices, power conversion systems, and inductive components. This method ensures reproducibility and repeatability, making it suitable for design verification, specification compliance, service evaluation, and research and development.

Key Topics

• Test Equipment and Setup

  • Requires a signal generator, broadband power amplifier, volt-amp-watt meter with current transformer, flux voltmeter, temperature chamber, and temperature sensors (Platinum RTD or Type T thermocouple).
  • Optional use of a personal computer with I/O control for automated data collection.

• Sample Preparation

  • Applicable to both toroidal and mated soft magnetic core components.
  • Care must be taken with mated cores to ensure minimal air gaps and proper clamping pressure to reduce measurement errors.

• Measurement Procedures

  • Test procedures cover the application of sinusoidal signals, temperature stabilization, and core loss measurement across different frequencies and temperatures.
  • Measurements are performed over a range of flux densities and are based on both SI and customary (inch-pound) units.

• Data Calculation and Reporting

  • Effective core dimensions, flux voltage, and specific core loss density are calculated using standardized equations.
  • Reporting includes details on test component, frequencies, flux densities, temperatures, and measured core loss values.

Applications

The ASTM A1013-00(2020) standard is widely used in industries where soft magnetic core components are critical, including:

• Electronics Manufacturing
  Ensures the quality and reliability of ferrite and iron powder cores used in transformers, inductors, and chokes for high-frequency circuits.

• Power Electronics
  Facilitates the performance evaluation of magnetic materials in power converters, power supplies, and switching devices operating in the kHz to MHz frequency range.

• Research and Development
  Provides a consistent framework for the experimental assessment and comparison of new magnetic core materials and shapes across laboratories.

• Quality Assurance and Specification Compliance
  Used for specification acceptance, batch testing, and service evaluation in procurement and supplier quality management.

By following the procedures in this standard, manufacturers and engineers can optimize core material selection, improve device efficiency, and ensure product compliance with global market requirements.

Related Standards

For broader context and integration into testing programs, consider the following related ASTM standards:

• ASTM A34/A34M - Practice for Sampling and Procurement Testing of Magnetic Materials
• ASTM A340 - Terminology of Symbols and Definitions Relating to Magnetic Testing
• ASTM E177 - Practice for Use of the Terms Precision and Bias in ASTM Test Methods

These standards provide additional guidance for terminology, sampling, and the interpretation of test results in the evaluation of magnetic materials.

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Keywords: high-frequency core loss, soft magnetic core, ASTM A1013, ferrite core, iron powder core, voltmeter-ammeter-wattmeter, magnetic material testing, toroidal core, mated core, core loss measurement, power electronics, specification acceptance, R&D, quality assurance, standard test method.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: A1013 − 00 (Reapproved 2020)
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.
1. Scope A34/A34MPractice for Sampling and Procurement Testing
of Magnetic Materials
1.1 This test method covers the equipment, procedures, and
A340Terminology of Symbols and Definitions Relating to
measurement of core loss of either toroidal or mated soft
Magnetic Testing
magnetic core components, such as soft ferrite cores, iron
E177Practice for Use of the Terms Precision and Bias in
powder cores, and so forth, over ranges of controlled ambient
ASTM Test Methods
temperatures typically from −20 to +120°C, frequencies from
10 kHz to 1 MHz, under sinusoidal flux conditions.
3. Terminology
1.2 The values and equations stated in customary (cgs-emu
3.1 The definitions of terms, symbols, and conversion fac-
and inch-pound) or SI units are to be regarded separately as
tors relating to magnetic testing, used in this test method, are
standard. Within this test method, SI units are shown in
found in Terminology A340.
brackets except for the sections concerning calculations where
there are separate sections for the respective unit systems. The 3.2 Definitions of Terms Specific to This Standard:
values stated in each system may not be exact equivalents; 3.2.1 bifilar transformer—a transformer in which the turns
therefore,eachsystemshallbeusedindependentlyoftheother. oftheprimaryandsecondarywindingsarewoundtogetherside
Combining values from the two systems may result in noncon- by side and in the same direction. This type of winding results
formance with this standard. in near unity coupling, so that there is a very efficient transfer
of energy from primary to secondary.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 3.2.2 core-loss density, P —core loss per unit volume in
cd
3 3
responsibility of the user of this standard to establish appro- mW/cm [W⁄m ].
priate safety, health, and environmental practices and deter-
3.2.3 effective permeability—the relative permeability of a
mine the applicability of regulatory limitations prior to use.
magneticcircuitincludingtheeffectofairgapsinthemagnetic
1.4 This international standard was developed in accor-
path length.
dance with internationally recognized principles on standard-
3.2.4 mated core set—twoormorecoresegmentsassembled
ization established in the Decision on Principles for the
with the magnetic flux path perpendicular to the mating
Development of International Standards, Guides and Recom-
surface.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
4. Significance and Use
4.1 Thistestmethodisdesignedfortestingofeithertoroidal
2. Referenced Documents
or mated soft magnetic core components over a range of
2.1 ASTM Standards:
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,
This test method is under the jurisdiction of ASTM Committee A06 on
service evaluation, and research and development.
MagneticPropertiesandisthedirectresponsibilityofSubcommitteeA06.01onTest
Methods.
CurrenteditionapprovedJune1,2020.PublishedJuly2020.Originallyapproved
5. Apparatus
ɛ1
in 2000. Last previous edition approved in 2013 as A1013 – 00 (2013) .
DOI:10.1520/A1013-00R20.
5.1 Theapparatusshallconsistofasmanyofthecomponent
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
partsasshownintheblockcircuitdiagrams(Figs.1and2)and
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
described as follows and in the appendix, as required to
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. perform the tests.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A1013 − 00 (2020)
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)
5.2 Signal Generator—A low distortion sine wave signal 5.6 Temperature Chamber, heated with electric elements,
generator is required. The frequency accuracy of the signal cooled by injecting liquid CO or liquid nitrogen into the air
generator should be within 60.1% with an output amplitude stream through an expansion nozzle or equivalent methods.
range from 1-mV to 10-V p-p.
5.7 Temperature with Platinum RTD or Type T Thermo-
5.3 Broadband Power Amplifier, capable of amplifying the couple.
output of the signal source by 50 dB.
5.8 Optional—Personal computer with appropriate I/O to
5.4 Volt-Amp-Watt Meter with Current Transformer, ac- control equipment and collect data.
coupled, broadband, power factor independent, true RMS
6. Test Core Component
reading instrument. Voltage channel minimum input imped-
ance1MΩ,voltagerangefrom2to100V,currentrangesfrom 6.1 The test core component can be of any magnetic
5 mA to 5A, power ranges from 100 mW to 500 W. The material (soft ferrite, iron powder, and so forth). The effective
full-scaleaccuracyofthewattmetershallnotexceed0.75%of permeability of the material must be sufficiently high so that
the product of the input voltage and current ranges. the test core component can be driven to the desired flux
density with the available test equipment (within the power
5.5 Flux Voltmeter—A full-wave true-averaging voltmeter
amplifier limitations).
with scale reading in average volts times 1.111 so that its
indications will be identical with those of a true rms voltmeter 6.2 When testing for material properties, the cross-sectional
onapuresinusoidalvoltage.Inputimpedanceofatleast2MΩ. areaofthetestcorecomponentshallbeuniformthroughoutits
To produce the estimated precision of test under this test entire magnetic path length. The core may be of any shape.
method, the full-scale meter errors shall not exceed 0.25%. Shapes with nonuniform cross-sectional areas within their
A1013 − 00 (2020)
magnetic path length can be tested for specific core shape 8. Calculation (Customary Units)
performance comparisons; however, the core-loss density will
8.1 The effective dimensional core parameters of the test
not be accurate, since the flux density and core loss vary
specimen are computed by normalizing the core area (A)
throughout the magnetic path length and are not uniform.
throughout the core’s magnetic path length (l). Core constants
6.3 Mated core set assembled around a prewound coil can C and C are calculated and used to calculate effective
1 2
be used, as well as toroidal cores. magnetic path length (l ), effective core cross-sectional area
6.3.1 Mating surfaces must be ground smooth and flat to (A ), and effective core volume (V ), as follows:
e e
minimize air gaps. Air gaps cause reluctance in the flux path n
n
and cause flux to fringe, both of which contribute to higher Coreconstant, C 5 cm (1)
1 (
A
n
measured losses.
n
n
6.3.2 Clamping pressure for the mated core set needs to be
Coreconstant, C 5 cm (2)
2 ( 2
An
sufficient to hold the cores together with minimum air gaps but
not so strong that it affects the properties of the material
~C !
...