ASTM A698/A698M-15
(Test Method)Standard Test Method for Magnetic Shield Efficiency in Attenuating Alternating Magnetic Fields
Standard Test Method for Magnetic Shield Efficiency in Attenuating Alternating Magnetic Fields
SIGNIFICANCE AND USE
5.1 This test method provides an easy, accurate, and reproducible method for determination of shielding factors (attenuation ratios) in simple alternating magnetic fields.
5.2 Since the sensing or pickup coil is of finite size, the measured shielding factor tends to be the average value for the space enclosed by the coil. Due care is required when interpreting results when the coil is located near an opening in the shield.
5.3 This test method is suitable for design, specification acceptance, service evaluation, quality assurance, and research purposes on magnetic shields.
5.4 Provided geometrically identical shields are compared, this test method is also suitable for evaluation and grading of magnetic shielding materials.
SCOPE
1.1 This test method covers the means for determining the performance quality of a magnetic shield when placed in a magnetic field of alternating polarity.
1.2 This test method provides a means of evaluating and grading magnetic shielding materials to determine their suitability for use in the production of magnetic shields.
1.3 This test method shall be used in conjunction with and shall conform to the requirements of Practice A34/A34M.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. 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 non-conformance with the standard.
1.5 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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Designation: A698/A698M − 15
Standard Test Method for
Magnetic Shield Efficiency in Attenuating Alternating
1
Magnetic Fields
This standard is issued under the fixed designationA698/A698M; 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.
1. Scope 3.2 Definitions of Terms Specific to This Standard:
3.2.1 attenuation ratio—the ratio of the measured voltage in
1.1 This test method covers the means for determining the
thepickupcoilbeforeandaftertheinsertionoftheshieldunder
performance quality of a magnetic shield when placed in a
test, E /E .
1 2
magnetic field of alternating polarity.
3.3 Abbreviations:
1.2 This test method provides a means of evaluating and
3.3.1 A—ac ammeter (usually root mean square (rms) but
grading magnetic shielding materials to determine their suit-
may be peak reading type).
ability for use in the production of magnetic shields.
3.3.2 E —voltage in the pickup coil, after establishing the
1
1.3 This test method shall be used in conjunction with and
field of test but before insertion of the shield into the test
shall conform to the requirements of Practice A34/A34M.
position.
1.4 The values stated in either SI units or inch-pound units
3.3.3 E —highest voltage observed in the pickup coil, at the
2
are to be regarded separately as standard. The values stated in
field of test, while rotating the test shield in the test position.
each system may not be exact equivalents; therefore, each
3.3.4 H —magnetic field strength, Oe [A/m].
p
system shall be used independently of the other. Combining
values from the two systems may result in non-conformance 3.3.5 I —ac magnetizing current, peak amperes.
p
with the standard.
3.3.6 I—ac magnetizing current, rms amperes.
1.5 This standard does not purport to address all of the
3.3.7 l —length of demagnetizing air coil, cm [m].
c
safety concerns, if any, associated with its use. It is the
3.3.8 N—number of turns per coil section (one half of total
responsibility of the user of this standard to establish appro-
Helmholtz coil turns).
priate safety and health practices and determine the applica-
3.3.9 N —number of turns in demagnetizing coil.
bility of regulatory limitations prior to use. 1
3.3.10 R—mean radius of Helmholtz coil, cm [m].
2. Referenced Documents
3.3.11 V—electronic voltmeter (average volts 3π/2 =2).
2
2.1 ASTM Standards:
A34/A34M Practice for Sampling and Procurement Testing
4. Summary of Test Method
of Magnetic Materials
4.1 Frequency—Tests under this test method are normally
A340 Terminology of Symbols and Definitions Relating to
conducted at a test frequency of 60 Hz.
Magnetic Testing
NOTE 1—Other test frequencies are used by mutual agreement. In
3. Terminology
general, as test frequencies are increased, it will be necessary to make
corresponding changes in pickup or test coils and in the size of the power
3.1 The following symbols and abbreviated definitions ap-
supply.
plyonlytothistestmethod(theofficialsymbolsanddefinitions
4.2 Magnetic Field Strength—Tests may be conducted at
are listed in Terminology A340):
any desired magnetic field strength. The standard test level for
ac magnetic fields is 0.5 or 2.0 peak Oe [39.8 or 159 peakA/m]
1
This test method is under the jurisdiction of ASTM Committee A06 on
and in the presence of the earth’s magnetic field (see 9.2).
MagneticPropertiesandisthedirectresponsibilityofSubcommitteeA06.01onTest
Methods.
4.3 Instrumentation—The instruments described are for use
Current edition approved April 1, 2015. Published May 2015. Originally
at 60 Hz. At higher frequencies, electronic voltmeters and
approved in 1974. Last previous edition approved in 2007 as A698/A698M–07.
DOI: 10.1520/A0698_A0698M-15.
preamplifiers should also be satisfactory. It may be necessary
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
to change the rms ammeter and power supplies for use at
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
higher test frequencies. It may also be desirable to reduce the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. number of area turns in the pickup coil at these frequencies.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
A698/A698M − 15
4.4 Field Attenuation—The usable range of attenuation
ratios is determined by the strength of the starting field and the
sensitivity of the available instrumentation. Measurements
shall not be made when signal voltages cannot be clearly
distingu
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: A698/A698M − 07 A698/A698M − 15
Standard Test Method for
Magnetic Shield Efficiency in Attenuating Alternating
1
Magnetic Fields
This standard is issued under the fixed designation A698/A698M; 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.
1. Scope
1.1 This test method covers the means for determining the performance quality of a magnetic shield when placed in a magnetic
field of alternating polarity.
1.2 This test method provides a means of evaluating and grading magnetic shielding materials to determine their suitability for
use in the production of magnetic shields.
1.3 This test method shall be used in conjunction with and shall conform to the requirements of Practice A34/A34M.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. 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 non-conformance with the standard.
1.5 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.
2. Referenced Documents
2
2.1 ASTM Standards:
A34/A34M Practice for Sampling and Procurement Testing of Magnetic Materials
A340 Terminology of Symbols and Definitions Relating to Magnetic Testing
3. Terminology
3.1 The following symbols and abbreviated definitions apply only to this test method (the official symbols and definitions are
listed in Terminology A340):
3.2 Definitions of Terms Specific to This Standard:
3.2.1 attenuation ratio—the ratio of the measured voltage in the pickup coil before and after the insertion of the shield under
test, E /E .
1 2
3.3 Abbreviations:
3.3.1 A—ac ammeter (usually root mean square (rms) but may be peak reading type).
3.3.2 E —voltage in the pickup coil, after establishing the field of test but before insertion of the shield into the test position.
1
3.3.3 E —highest voltage observed in the pickup coil, at the field of test, while rotating the test shield in the test position.
2
3.3.4 H —magnetic field strength, Oe [A/m].
p
3.3.5 I —ac magnetizing current, peak amperes.
p
3.3.6 I—ac magnetizing current, rms amperes.
3.3.7 l —length of demagnetizing air coil, cm [m].
c
3.3.8 N—number of turns per coil section (one half of total Helmholtz coil turns).
1
This test method is under the jurisdiction of ASTM Committee A06 on Magnetic Properties and is the direct responsibility of Subcommittee A06.01 on Test Methods.
Current edition approved May 1, 2007April 1, 2015. Published June 2007May 2015. Originally approved in 1974. Last previous edition approved in 20022007 as
A698/A698M–02.–07. DOI: 10.1520/A0698_A0698M-07.10.1520/A0698_A0698M-15.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
A698/A698M − 15
3.3.9 N —number of turns in demagnetizing coil.
1
3.3.10 R—mean radius of Helmholtz coil, cm [m].
3.3.11 V—electronic voltmeter (average volts 3π/2 =2).
4. Summary of Test Method
4.1 Frequency—Tests under this test method are normally conducted at a test frequency of 60 Hz.
NOTE 1—Other test frequencies are used by mutual agreement. In general, as test frequencies are increased, it will be necessary to make corresponding
changes in pickup or test coils and in the size of the power supply.
4.2 Magnetic Field Strength—Tests may be conducted at any desired magnetic field strength. The standard test level for ac
magnetic fields is 0.5 or 2.0 peak Oe [40[39.8 or 160159 peak A/m] and in the presence of the earth’s magnetic field (see 9.2).
4.3 Instrumentation—The instruments described are for use at 60 Hz. At higher frequencies, electronic voltmeters and
preamplifiers should also be satisfactory. It may be necessary to change the rms ammeter and power supplies fo
...
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