ASTM A340-23

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Designation: A340 − 22 A340 − 23
Standard Terminology of
1
Symbols and Definitions Relating to Magnetic Testing
This standard is issued under the fixed designation A340; 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.
INTRODUCTION
In preparing this terminology standard, an attempt has been made to avoid, where possible, vector
analysis and differential equations so as to make the definitions more intelligible to the average worker
in the field of magnetic testing. In some cases, rigorous treatment has been sacrificed to secure
simplicity and clarity, but it is believed that none of the definitions will prove to be misleading.
It is the intent of this terminology standard to be consistent in the use of symbols and units with
those found in IEC 60050-221:1990 International Electrotechnical Vocabulary Chapter 221: Magnetic
materials and components. Although Committee A06 has chosen to make SI units normative, the
extensive technical and commercial literature using the older Gaussian units requires that many
definitions contain discussion about and use of both unit systems. This is not an endorsement of the
older unit system and users of this terminology are encouraged to use SI units where possible.
1. Referenced Documents
2
1.1 ASTM Standards:
A343/A343M Test Method for Alternating-Current Magnetic Properties of Materials at Power Frequencies Using Wattmeter-
Ammeter-Voltmeter Method and 25-cm Epstein Test Frame
A772/A772M Test Method for AC Magnetic Permeability of Materials Using Sinusoidal Current
2. Terminology
Part 1—Symbols Used in Magnetic Testing
Symbol Term
a cross-sectional area of B coil
A cross-sectional area of specimen
A' solid area
B
magnetic flux density
H
magnetic induction
∆B excursion range of induction
B biased flux density
b
B demagnetization flux density
d
B H energy product
d d
(BH) maximum energy product
max
1
This terminology is under the jurisdiction of ASTM Committee A06 on Magnetic Properties and is the direct responsibility of Subcommittee A06.92 on Terminology
and Definitions.
Current edition approved July 1, 2022May 1, 2023. Published July 2022May 2023. Originally approved in 1949. Last previous edition approved in 20212022 as
A340 – 21.A340 – 22. DOI: 10.1520/A0340-22.10.1520/A0340-23.
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.
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A340 − 23
B incremental flux density
∆
B intrinsic flux density
i
B maximum value of magnetic flux density in a
m
static hysteresis loop
B maximum value of magnetic flux density in a
max
dynamic hysteresis loop
B residual flux density
r
B saturation flux density
s
cf crest factor
CM cyclically magnetized condition
d lamination thickness
df distortion factor
D magnetic dissipation factor
m
E exciting voltage
E induced primary voltage
1
E induced secondary voltage
2
E flux volts
f
f cyclic frequency in hertz
^ magnetomotive force
ff form factor
H magnetic field strength
∆H excursion range of magnetic field strength
H biasing magnetic field strength
b
H coercive field strength
cB
H intrinsic coercive field strength
cJ
H demagnetizing field strength
d
H incremental magnetic field strength
∆
H ac magnetic field strength (from an assumed
L
peak value of magnetizing current)
H maximum magnetic field strength in a hyster-
m
esis loop
H maximum magnetic field strength in a flux-
max
current loop
H ac magnetic field strength (from a measured
p
peak value of exciting current)
H instantaneous magnetic field strength (coinci-
t
dent with B )
max
H ac magnetic field strength (from an assumed
z
peak value of exciting current)
I ac exciting current (rms value)
I ac core loss current (rms value)
c
I constant current
dc
I ac magnetizing current (rms value)
m
J magnetic polarization
J residual magnetic polarization
r
J saturation magnetic polarization
s
k' coupling coefficient
! flux path length
! effective flux path length
1
! gap length
g
+ (also φ N ) flux linkage
+ mutual flux linkage
m
L self inductance
L core inductance
1
L incremental inductance
...