ASTM A889/A889M-14(2020)

Standard Test Method for Alternating-Current Magnetic Properties of Materials at Low Magnetic Flux Density Using the Voltmeter-Ammeter-Wattmeter-Varmeter Method and 25-cm Epstein Frame

SIGNIFICANCE AND USE
3.1 This test method may be used to determine the specific core loss, specific reactive power, specific exciting power, inductance permeability, and impedance permeability of flat-rolled magnetic materials over a wide range of inductions and at frequencies up to 400 Hz for symmetrically magnetized test samples.  
3.2 These measurements are used by the producer and user of the flat-rolled material for quality control purposes. The fundamental assumption inherent in these measurements is that they can be correlated with the electromagnetic characteristics of a core fabricated from the flat-rolled material.
SCOPE
1.1 This test method covers tests for the magnetic properties of basic flat-rolled magnetic materials at power frequencies (25 to 400 Hz) using a 25-cm Epstein test frame and the 25-cm double-lap-jointed core.  
1.2 The magnetic properties of materials are determined from measurements on Epstein core specimens with the core and test coils treated as though they constituted a series-parallel equivalent circuit (Fig. A1.1) for the fundamental frequency of excitation where the apparent parallel inductance, L1, and resistance, R1, are attributable to the test specimen.  
1.3 This test method is suitable for the determination of core loss, rms volt-amperes, rms exciting current, reactive volt-amperes, and related properties of flat-rolled magnetic materials under ac magnetization.  
1.4 The frequency range of this test method is normally that of the commercial power frequencies 50 to 60 Hz. It is also acceptable for measurements at frequencies from 25 to 400 Hz. This test method is customarily used on nonoriented electrical steels at inductions up to 10 kG [1.0 T] and for grain-oriented electrical steels at inductions up to 15 kG [1.5 T].  
1.5 For reactive properties, both flux and current waveforms introduce limitations. Over its range of useful inductions, the varmeter is valid for the measurement of reactive volt-amperes (vars) and inductance permeability. For the measurement of these properties, it is suggested that test inductions be limited to values sufficiently low that the measured values of vars do not differ by more than 15 % (Note 1) from those calculated from the measured values of exciting volt-amperes and core loss.  
Note 1: This limitation is placed on this test method in consideration of the nonlinear nature of the magnetic circuit, which leads to a difference between vars based on fundamental frequency components of voltage and current and current after harmonic rejection and vars computed from rms current, voltage, and watt values when one or more of these quantities are nonsinusoidal.  
1.6 This test method shall be used in conjunction with Practice A34/A34M.  
1.7 Explanation of terms, symbols, and definitions used may be found in the various sections of this test method. The official list of definitions and symbols may be found in Terminology A340.  
1.8 The values and equations stated in customary (cgs-emu and inch-pound) or SI units are to be regarded separately as standard. Within this standard, 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.  
1.9 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.  
1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Stand...

General Information

• Status: Published
• Publication Date: 31-May-2020
• ICS: 29.030 - Magnetic materials
• Technical Committee: A06 - Magnetic Properties
• Drafting Committee: A06.01 - Test Methods

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: A889/A889M − 14 (Reapproved 2020)
Standard Test Method for
Alternating-Current Magnetic Properties of Materials at Low
Magnetic Flux Density Using the Voltmeter-Ammeter-
1
Wattmeter-Varmeter Method and 25-cm Epstein Frame
This standard is issued under the fixed designationA889/A889M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
current and current after harmonic rejection and vars computed from rms
1. Scope
current, voltage, and watt values when one or more of these quantities are
1.1 This test method covers tests for the magnetic properties
nonsinusoidal.
ofbasicflat-rolledmagneticmaterialsatpowerfrequencies(25
1.6 This test method shall be used in conjunction with
to 400 Hz) using a 25-cm Epstein test frame and the 25-cm
Practice A34/A34M.
double-lap-jointed core.
1.7 Explanationofterms,symbols,anddefinitionsusedmay
1.2 The magnetic properties of materials are determined
befoundinthevarioussectionsofthistestmethod.Theofficial
from measurements on Epstein core specimens with the core
list of definitions and symbols may be found in Terminology
andtestcoilstreatedasthoughtheyconstitutedaseries-parallel
A340.
equivalent circuit (Fig.A1.1) for the fundamental frequency of
1.8 The values and equations stated in customary (cgs-emu
excitation where the apparent parallel inductance, L , and
1
and inch-pound) or SI units are to be regarded separately as
resistance, R , are attributable to the test specimen.
1
standard. Within this standard, SI units are shown in brackets
1.3 Thistestmethodissuitableforthedeterminationofcore
except for the sections concerning calculations where there are
loss, rms volt-amperes, rms exciting current, reactive volt-
separate sections for the respective unit systems. The values
amperes, and related properties of flat-rolled magnetic materi-
stated in each system may not be exact equivalents; therefore,
als under ac magnetization.
each system shall be used independently of the other. Combin-
1.4 The frequency range of this test method is normally that
ingvaluesfromthetwosystemsmayresultinnonconformance
of the commercial power frequencies 50 to 60 Hz. It is also
with this standard.
acceptable for measurements at frequencies from 25 to 400 Hz.
1.9 This standard does not purport to address all of the
This test method is customarily used on nonoriented electrical
safety concerns, if any, associated with its use. It is the
steels at inductions up to 10 kG [1.0 T] and for grain-oriented
responsibility of the user of this standard to establish appro-
electrical steels at inductions up to 15 kG [1.5 T].
priate safety, health, and environmental practices and deter-
1.5 Forreactiveproperties,bothfluxandcurrentwaveforms mine the applicability of regulatory limitations prior to use.
introduce limitations. Over its range of useful inductions, the
1.10 This international standard was developed in accor-
varmeter is valid for the measurement of reactive volt-amperes dance with internationally recognized principles on standard-
(vars) and inductance permeability. For the measurement of
ization established in the Decision on Principles for the
these properties, it is suggested that test inductions be limited Development of International Standards, Guides and Recom-
to values sufficiently low that the measured values of vars do
mendations issued by the World Trade Organization Technical
not differ by more than 15 % (Note 1) from those calculated Barriers to Trade (TBT) Committee.
from the measured values of exciting volt-amperes and core
2. Referenced Documents
loss.
2
2.1 ASTM Standards:
NOTE 1—This limitation is placed on this test method in consideration
A34/A34M Practice for Sampling and Procurement Testing
of the nonlinear nature of the magnetic circuit, which leads to a difference
between vars based on fundamental frequency components of voltage and of Magnetic Materials
A340 Terminology of Symbols and Definitions Relating to
Magnetic Testing
1
This test method is under the jurisdiction of ASTM Committee A06 on
MagneticPropertiesandisthedirectresponsibilityofSubcommitteeA06.01onTest
2
Methods. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
CurrenteditionapprovedJune1,2020.PublishedJuly2020.Originallyapproved contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
in 1988. Last previous edition approved in 2014 as A889/A889M – 14. DOI: Standards volume information, refer to the stand
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