Standard Test Method for Alternating Current Magnetic Properties of Materials Using the Wattmeter-Ammeter-Voltmeter Method, 100 to 10 000 Hz and 25-cm Epstein Frame

SIGNIFICANCE AND USE
This test method evaluates the performance of flat-rolled magnetic materials over a wide frequency range of ac excitation with and without incremental dc bias, as used on transformers, motors, and other laminated core devices.
This test method is suitable for design, specification acceptance, service evaluation, and research.
The application of test results obtained with this test method to the design or evaluation of a particular magnetic device must recognize the influence of the magnetic circuitry upon its performance. Some specific items to consider are size, shape, holes, welding, staking, bolting, bracketing, shorting between laminations, ac waveform, adjacent magnetic fields, and stress.
SCOPE
1.1 This test method covers the determination of the magnetic properties of flat-rolled magnetic materials using Epstein test specimens with double-lap joints in the 25-cm Epstein frame. It covers determination of core loss, rms and peak exciting current, exciting power, magnetic field strength, and permeability. This test method is commonly used to test grain-oriented and nonoriented electrical steels but may also be used to test nickel-iron, cobalt-iron, and other flat-rolled magnetic materials.
1.2 This test method shall be used in conjunction with Practice A 34/A 34M and Test Method A 343/A 343M.
1.3 Tests under this test method may be conducted with either normal ac magnetization or with ac magnetization and superimposed dc bias (incremental magnetization).
1.4 In general, this test method has the following limitations:
1.4.1 FrequencyThe range of this test method normally covers frequencies from 100 to 10 000 Hz. With proper equipment, the test method may be extended above 10 000 Hz. When tests are limited to the use of power sources having frequencies below 100 Hz, they shall use the procedures of Test Method A 343/A 343M.
1.4.2 Magnetic Flux Density(may also be referred to as Flux Density)-The range of magnetic flux density for this test method is governed by the test specimen properties and by the available instruments and other equipment components. Normally, for many materials, the magnetic flux density range is from 1 to 15 kG [0.1 to 1.5 T].
1.4.3 Core Loss and Exciting PowerThese measurements are normally limited to test conditions that do not cause a test specimen temperature rise in excess of 50C or exceed 100 W/lb [220 W/kg].
1.4.4 ExcitationEither rms or peak values of exciting current may be measured at any test point that does not exceed the equipment limitations provided that the impedance of the ammeter shunt is low and its insertion into the test circuit does not cause appreciably increased voltage waveform distortion at the test magnetic flux density.
1.4.5 Incremental PropertiesMeasurement of incremental properties shall be limited to combinations of ac and dc excitations that do not cause secondary voltage waveform distortion, as determined by the form factor method, to exceed a shift of 10 % away from sine wave conditions.
1.5 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.
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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Status
Historical
Publication Date
31-Oct-2005
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Drafting Committee
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ASTM A348/A348M-05 - Standard Test Method for Alternating Current Magnetic Properties of Materials Using the Wattmeter-Ammeter-Voltmeter Method, 100 to 10 000 Hz and 25-cm Epstein Frame
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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:A348/A348M–05
Standard Test Method for
Alternating Current Magnetic Properties of Materials Using
the Wattmeter-Ammeter-Voltmeter Method, 100 to 10000 Hz
1
and 25-cm Epstein Frame
This standard is issued under the fixed designationA348/A348M; 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 1.4.4 Excitation—Either rms or peak values of exciting
current may be measured at any test point that does not exceed
1.1 This test method covers the determination of the mag-
the equipment limitations provided that the impedance of the
netic properties of flat-rolled magnetic materials using Epstein
ammeter shunt is low and its insertion into the test circuit does
test specimens with double-lap joints in the 25-cm Epstein
notcauseappreciablyincreasedvoltagewaveformdistortionat
frame. It covers determination of core loss, rms and peak
the test magnetic flux density.
exciting current, exciting power, magnetic field strength, and
1.4.5 Incremental Properties—Measurement of incremental
permeability. This test method is commonly used to test
properties shall be limited to combinations of ac and dc
grain-orientedandnonorientedelectricalsteelsbutmayalsobe
excitations that do not cause secondary voltage waveform
used to test nickel-iron, cobalt-iron, and other flat-rolled
distortion, as determined by the form factor method, to exceed
magnetic materials.
a shift of 10% away from sine wave conditions.
1.2 This test method shall be used in conjunction with
1.5 The values and equations stated in customary (cgs-emu
Practice A34/A34M and Test Method A343/A343M.
and inch-pound) or SI units are to be regarded separately as
1.3 Tests under this test method may be conducted with
standard. Within this standard, SI units are shown in brackets
either normal ac magnetization or with ac magnetization and
except for the sections concerning calculations where there are
superimposed dc bias (incremental magnetization).
separate sections for the respective unit systems. The values
1.4 In general, this test method has the following limita-
stated in each system may not be exact equivalents; therefore,
tions:
each system shall be used independently of the other. Combin-
1.4.1 Frequency—The range of this test method normally
ingvaluesfromthetwosystemsmayresultinnonconformance
covers frequencies from 100 to 10000 Hz. With proper
with this standard.
equipment,thetestmethodmaybeextendedabove10000Hz.
1.6 This standard does not purport to address all of the
When tests are limited to the use of power sources having
safety concerns, if any, associated with its use. It is the
frequenciesbelow100Hz,theyshallusetheproceduresofTest
responsibility of the user of this standard to establish appro-
Method A343/A343M.
priate safety and health practices and determine the applica-
1.4.2 Magnetic Flux Density (may also be referred to as
bility of regulatory limitations prior to use.
Flux Density)—Therangeofmagneticfluxdensityforthistest
method is governed by the test specimen properties and by the
2. Referenced Documents
available instruments and other equipment components. Nor-
2
2.1 ASTM Standards:
mally, for many materials, the magnetic flux density range is
A34/A34M Practice for Sampling and Procurement Testing
from 1 to 15 kG [0.1 to 1.5 T].
of Magnetic Materials
1.4.3 Core Loss and Exciting Power—These measurements
A340 Terminology of Symbols and Definitions Relating to
are normally limited to test conditions that do not cause a test
Magnetic Testing
specimen temperature rise in excess of 50°C or exceed 100
A343/A343M Test Method for Alternating-Current Mag-
W/lb [220 W/kg].
netic Properties of Materials at Power Frequencies Using
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
Current edition approved Nov. 1, 2005. Published December 2005. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1960. Last previous edition approved in 2000 as A348/A348M–00. Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/A0348_A0348M-05. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

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A348/A348M–05
TABLE 1 Number of Strips for Various Nominal Specimen
Wattmeter-Ammeter-VoltmeterMethodand25-cmEpstein
Weight Epstein Frames (Minimum Strip Length is 28 cm [280
...

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