ASTM A1013-00(2005)
(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
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.
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 +120C, 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) 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.
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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Standards Content (Sample)
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Designation: A1013 − 00(Reapproved 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
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 3. Terminology
1.1 This test method covers the equipment, procedures, and
3.1 The definitions of terms, symbols, and conversion fac-
measurement of core loss of either toroidal or mated soft tors relating to magnetic testing, used in this test method, are
magnetic core components, such as soft ferrite cores, iron
found in Terminology A340.
powder cores, and so forth, over ranges of controlled ambient
3.2 Definitions of Terms Specific to This Standard:
temperatures typically from −20 to +120°C, frequencies from
3.2.1 bifilar transformer—a transformer in which the turns
10 kHz to 1 MHz, under sinusoidal flux conditions.
oftheprimaryandsecondarywindingsarewoundtogetherside
1.2 The values and equations stated in customary (cgs-emu
by side and in the same direction. This type of winding results
and inch-pound) of SI units are to be regarded separately as in near unity coupling, so that there is a very efficient transfer
standard. Within this test method, SI units are shown in
of energy from primary to secondary.
brackets except for the sections concerning calculations where
3.2.2 core-loss density, P —core loss per unit volume in
cd
there are separate sections for the respective unit systems. The 3 3
mW/cm [W/m ].
values stated in each system may not be exact equivalents;
3.2.3 effective permeability—the relative permeability of a
therefore,eachsystemshallbeusedindependentlyoftheother.
magneticcircuitincludingtheeffectofairgapsinthemagnetic
Combiningvaluesfromthetwosystemsmayresultinnoncon-
path length.
formance with this standard.
3.2.4 matedcoreset—twoormorecoresegmentsassembled
1.3 This standard does not purport to address all of the
with the magnetic flux path perpendicular to the mating
safety concerns, if any, associated with its use. It is the
surface.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4. Significance and Use
bility of regulatory limitations prior to use.
4.1 Thistestmethodisdesignedfortestingofeithertoroidal
2. Referenced Documents
or mated soft magnetic core components over a range of
temperatures, frequencies, and flux densities.
2.1 ASTM Standards:
A34/A34MPractice for Sampling and Procurement Testing
4.2 The reproducibility and repeatability of this test method
of Magnetic Materials
are such that it is suitable for design, specification acceptance,
A340Terminology of Symbols and Definitions Relating to
service evaluation, and research and development.
Magnetic Testing
E177Practice for Use of the Terms Precision and Bias in
5. Apparatus
ASTM Test Methods
5.1 Theapparatusshallconsistofasmanyofthecomponent
partsasshownintheblockcircuitdiagrams(Figs.1and2)and
described as follows and in the appendix, as required to
This test method is under the jurisdiction of ASTM Committee A06 on
perform the tests.
MagneticPropertiesandisthedirectresponsibilityofSubcommitteeA06.01onTest
Methods.
5.2 Signal Generator—A low distortion sine wave signal
Current edition approved Nov. 1, 2005. Published November 2005. Originally
generator is required. The frequency accuracy of the signal
approved in 2000. Last previous edition approved in 2000 as A1013–00.
generator should be within 60.1% with an output amplitude
DOI:10.1520/A1013–00R05.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or range from 1-mV to 10-V p-p.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.3 Broadband Power Amplifier, capable of amplifying the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. output of the signal source by 50 dB.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A1013 − 00 (2005)
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)
5.4 Volt-Amp-Watt Meter with Current Transformer, ac- 5.8 Optional—Personal computer with appropriate I/O to
coupled, broadband, power factor independent, true RMS control equipment and collect data.
reading instrument. Voltage channel minimum input imped-
ance1MΩ,voltagerangefrom2to100V,currentrangesfrom
6. Test Core Component
5 mA to 5A, power ranges from 100 mW to 500 W. The
6.1 The test core component can be of any magnetic
full-scaleaccuracyofthewattmetershallnotexceed0.75%of
material (soft ferrite, iron powder, and so forth). The effective
the product of the input voltage and current ranges.
permeability of the material must be sufficiently high so that
5.5 Flux Voltmeter—A full-wave true-averaging voltmeter
the test core component can be driven to the desired flux
with scale reading in average volts times 1.111 so that its
density with the available test equipment (within the power
indications will be identical with those of a true rms voltmeter
amplifier limitations).
onapuresinusoidalvoltage.Inputimpedanceofatleast2MΩ.
6.2 When testing for material properties, the cross-sectional
To produce the estimated precision of test under this test
areaofthetestcorecomponentshallbeuniformthroughoutits
method, the full-scale meter errors shall not exceed 0.25%.
entire magnetic path length. The core may be of any shape.
5.6 Temperature Chamber, heated with electric elements,
Shapes with nonuniform cross-sectional areas within their
cooled by injecting liquid CO or liquid nitrogen into the air
magnetic path length can be tested for specific core shape
stream through an expansion nozzle or equivalent methods.
performance comparisons; however, the core-loss density will
5.7 Temperature with Platinum RTD or Type T Thermo- not be accurate, since the flux density and core loss vary
couple. throughout the magnetic path length and are not uniform.
A1013 − 00 (2005)
6.3 Mated core set assembled around a prewound coil can throughout the core’s magnetic path length (l). Core constants
be used, as well as toroidal cores. C and C are calculated and used to calculate effective
1 2
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
sufficienttoholdthecorestogetherwithminimumairgapsbut
n
n
not so strong that it affects the properties of the material
Coreconstant, C 5 cm (2)
2 (
An
through the creation of stress-magnetostriction anisotropy. A
pressure of 5 lb/in. [35 kPa] is recommended where the area
C
~ !
is the area of the mating surfaces. 1
Effectivemagneticpathlength, l 5 cm (3)
C
6.4 The length of test leads from the measuring instruments
tothetestcorecomponentshouldbeminimized.Thetestleads
C
should be twisted pairs to minimize magneti
...
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