1、Designation: A340 17aA340 18Standard Terminology ofSymbols and Definitions Relating to Magnetic Testing1This standard is issued under the fixed designation A340; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONIn preparing this glossary of terms, terminology standard, an attempt has been made to avoid, wherepossible, vector analysis an
3、d differential equations so as to make the definitions more intelligible tothe average worker in the field of magnetic testing. In some cases, rigorous treatment has beensacrificed to secure simplicity, simplicity and clarity, but it is believed that none of the definitions willprove to be misleadin
4、g.It is the intent of this glossary terminology standard to be consistent in the use of symbols and unitswith those found in ANSI/IEEE 260-1978 and USA Standard Y 10.5-1968.IEC 60050-221:1990International Electrotechnical Vocabulary Chapter 221: Magnetic materials and components.AlthoughCommittee A0
5、6 has chosen to make SI units normative, the extensive technical and commercialliterature using the older Gaussian units requires that many definitions contain discussion about anduse of both unit systems. This is not an endorsement of the older unit system and users of thisterminology are encourage
6、d to use SI units where possible.Part 1Symbols Used in Magnetic TestingSymbol Term cross-sectional area of B coilA cross-sectional area of specimenA solid areaB Hmagnetic flux densitymagnetic inductionB excursion range of inductionBb biased inductionBd remanent inductionBdm remanenceBdHd energy prod
7、uct(BH)max maximum energy productB incremental inductionBi intrinsic inductionBi intrinsic flux densityBm maximum induction in a hysteresis loopBmax maximum induction in a flux current loopBr residual inductionBrs retentivityBs saturation inductioncf crest factorCM cyclically magnetized conditiond l
8、amination thicknessDB demagnetizing coefficientdf distortion factorDm magnetic dissipation factorE exciting voltageE1 induced primary voltage1 This terminology is under the jurisdiction of ASTM Committee A06 on Magnetic Properties and is the direct responsibility of Subcommittee A06.92 on Terminolog
9、yand Definitions.Current edition approved Oct. 15, 2017June 1, 2018. Published October 2017July 2018. Originally approved in 1949. Last previous edition approved in 2017 asA340 17.A340 17a. DOI: 10.1520/A0340-17A.10.1520/A0340-18.This document is not an ASTM standard and is intended only to provide
10、the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit 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 versionof the stan
11、dard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1E2 induced secondary voltageEf flux voltsf cyclic frequency in hertz magnetomotive forceff form factorH magnetic field
12、 strengthH excursion range of magnetic field strengthHb biasing magnetic field strengthHcB coercive field strengthHcJ intrinsic coercive field strengthHd demagnetizing field strengthH incremental magnetic field strengthHg air gap magnetic field strengthHL ac magnetic field strength (from an assumedp
13、eak value of magnetizing current)Hm maximum magnetic field strength in a hyster-esis loopHmax maximum magnetic field strength in a flux-current loopHp ac magnetic field strength (from a measuredpeak value of exciting current)Ht instantaneous magnetic field strength (coinci-dent with Bmax)Hz ac magne
14、tic field strength force (from an as-sumed peak value of exciting current)Hz ac magnetic field strength (from an assumedpeak value of exciting current)I ac exciting current (rms value)Ic ac core loss current (rms value)Idc constant currentIm ac magnetizing current (rms value)J magnetic polarizationk
15、 coupling coefficient! flux path length!1 effective flux path length!g gap length+ (also N ) flux linkage+m mutual flux linkageL self inductanceL1 core inductanceL incremental inductanceLi intrinsic inductanceLm mutual inductanceL0 initial inductanceLs series inductanceLw winding inductancem magneti
16、c momentM magnetizationm total mass of a specimenm1 active mass of a specimenND demagnetizing factorN1 turns in a primary windingN2 turns in a secondary windingN1I/!1 ac excitationp magnetic pole strength3 permeanceP active (real) powerPa apparent powerPa (B;f) specific apparent powerPc total core l
17、ossPc (B;f) specific core lossPc incremental core lossPe normal eddy current core lossPe incremental eddy current core lossPh normal hysteresis core lossPh incremental hysteresis core lossPq reactive (quadrature) powerPr residual core lossPw winding loss (copper loss)Pz exciting powerPz (B;f) specif
18、ic exciting powerQm magnetic storage factor5 reluctanceR1 core resistanceRw winding resistanceS lamination factor (stacking factor)SCM symmetrically cyclically magnetized conditionTc Curie temperatureA340 182w lamination widthWh hysteresis loop loss linear expansion, coefficient (average) incrementa
19、l tolerance hysteretic angle loss anglecos magnetic power factorp proton gyromagnetic ratio0 magnetic constant density susceptibilityac Permeabilities:a ideal permeabilityL inductance permeabilityL incremental inductance permeability0d initial dynamic permeabilityp peak permeabilityp incremental pea
20、k permeabilityi instantaneous permeabilityz impedance permeabilityz incremental impedance permeabilitydc Permeabilities: normal permeabilityabs absolute permeabilityd differential permeability incremental permeabilityeff effective circuit permeabilityi incremental intrinsic permeabilitym maximum per
21、meabilityi initial permeabilityr relative permeabilityrev reversible permeability/cot figure of merit reluctivity the numeric 3.1416 resistivity magnetic fluxN flux linkage (see +) mass susceptibility0 initial susceptibility angular frequency in radians per secondPart 2Definition of Terms Used in Ma
22、gnetic Testingac excitation, N1I/1the ratio of the rms ampere-turns of exciting current in the primary winding of an inductor to the effectiveflux path length of the inductor.active (real) power, Pthe product of the rms current, I, in an electrical circuit, the rms voltage, E, across the circuit, an
23、d thecosine of the angular phase difference, between the current and the voltage.P 5 EI cosDISCUSSIONThe portion of the active power that is expended in a magnetic core is the total core loss, Pc.aging coefficientthe percentage change in a specific magnetic property resulting from a specific aging t
24、reatment.DISCUSSIONThe aging treatments usually specified are:(a) 100 h at 150C or(b) 600 h at 100C.aging, magneticthe change in the magnetic properties of a material resulting from metallurgic change due to a normal orspecified aging condition.DISCUSSIONThis term implies a deterioration of the magn
25、etic properties of magnetic materials for electronic and electrical applications, unless otherwise specified.A340 183air-gap magnetic field strength, Hgthe magnetic field strength required to produce the induction magnetic flux density existingat some point in a nonmagnetic gap in a magnetic circuit
26、.DISCUSSIONIn the cgs-emu system of units, Hg is numerically equal to the induction magnetic flux density existing at such a point and exceeds the magnetic fieldstrength in the magnetic material.amorphous alloya semiprocessed alloy produced by a rapid quenching, direct casting process resulting in m
27、etals withnoncrystalline structure.ampere (turn),Athe unit of magnetomotive force in the SI system of units. The symbolArepresents the unit of electric current,ampere, in the SI system of units.ampere per metre, A/mthe unit of magnetic field strength in the SI system of units.anisotropic materiala m
28、aterial in which the magnetic properties differ in various directions.anisotropy of lossthe ratio of the specific core loss measured with flux parallel to the rolling direction to the specific core losswith flux perpendicular to the rolling direction.anisotropy of loss5Pc B;f! lPc B;f! twhere:Pc (B;
29、f) l = specific core loss value with flux parallel to the rolling direction, W/lb W/kg, andPc (B;f) t = specific core loss value with flux perpendicular to the rolling direction, W/lb W/kg.DISCUSSIONThis definition of anisotropy normally applies to electrical steels with measurements made in an Epst
30、ein frame at a flux density of 15 kG 1.5 T anda frequency of 60 Hz (see Test Method A343).anisotropy of permeabilitythe ratio of relative peak permeability measured with flux parallel to the rolling direction to therelative peak permeability measured with flux perpendicular to the rolling direction.
31、anisotropy of permeability5prlprtwhere:prl = relative peak permeability value with flux parallel to the rolling direction, andprt = relative peak permeability value with flux perpendicular to the rolling direction.DISCUSSIONThis definition of anisotropy normally applies to electrical steels with mea
32、surements made in an Epstein frame at a flux density of 15 kG 1.5 T anda frequency of 60 Hz (see Test Method A343).antiferromagnetic materiala feebly magnetic material in which almost equal magnetic moments are lined up antiparallel toeach other. Its susceptibility increases as the temperature is ra
33、ised until a critical (Nel) temperature is reached; above thistemperature the material becomes paramagnetic.apparent power, Pathe product (volt-amperes) of the rms exciting current and the applied rms terminal voltage in an electriccircuit containing inductive impedance. The components of this imped
34、ance as a result of the winding will be linear, while thecomponents as a result of the magnetic core will be nonlinear. The unit of apparent power is the volt-ampere, VA.apparent power, specific, Pa(B;f)the value of the apparent power divided by the active mass of the specimen, that is,volt-amperes
35、per unit mass. The values of voltage and current are those developed at a maximum value of cyclically varyinginduction magnetic flux density B and specified frequency f.area, Athe geometric cross-sectional area of a magnetic path which is perpendicular to the direction of the induction.magneticflux
36、density.A340 184B(H) loopa hysteresis loop where the magnetic flux density (B) is plotted as a function of the magnetic field strength (H). Unlessotherwise stated, it is assumed that the loop represents the SCM condition and therefore has 180 rotational symmetry about theorigin of the coordinate sys
37、tem.Bi(H) loopa hysteresis loop where the intrinsic flux density (Bi) is plotted as a function of the magnetic field strength (H). Unlessotherwise stated, it is assumed that the loop represents the SCM condition and therefore has 180 rotational symmetry about theorigin of the coordinate system.Bloch
38、 walla domain wall in which the magnetic moment at any point is substantially parallel to the wall surface. See alsodomain wall.Bohr magnetona constant that is equal to the magnetic moment of an electron because of its spin. The value of the constantis (9 274 078 1021 erg/gauss or 9 274 078 1024 J/T
39、).cgs-emu system of unitsthe system for measuring physical quantities in which the base units are the centimetre, gram, andsecond, and the numerical value of the magnetic constant, 0, is unity.coercive field strength, HcBthe absolute value of the applied magnetic field strength (H) required to resto
40、re the magnetic fluxdensity (B) to zero.DISCUSSIONThe symbol Hc has historically been used to denote the coercive field strength determined from a (B,HB(H) loop. Further use of this symbol inASTMA06 standards is deprecated.DISCUSSIONThe coercive field strength monotonically increases with increasing
41、 maximum magnetic field strength (Hm) reaching a maximum or limiting valuetermed the coercivity. Unless it is known that the material has been magnetized to saturation, the term coercive field strength is preferred.DISCUSSIONThe coercive field strength is not completely described without knowing the
42、 maximum magnetic flux density (Bm) or maximum magnetic field strength(Hm) used in the measurement.coercive field strength, intrinsic, HcJthe absolute value of the applied magnetic field strength (H) required to restore either themagnetic polarization (J) or magnetization (M) to zero.DISCUSSIONThe s
43、ymbol Hci has historically been used to denote the intrinsic coercive field strength determined from a (Bi,(H)H) loop. Further use of this symbolin ASTM A06 standards is deprecated.DISCUSSIONThe intrinsic coercive field strength monotonically increases with increasing maximum magnetic field strength
44、 (Hm) reaching a maximum or limitingvalue termed the intrinsic coercivity. Unless it is known that the material has been magnetized to saturation, the term intrinsic coercive field strengthis preferred.DISCUSSIONThe measured value of intrinsic coercive field strength will be the same whether it is m
45、easured from a magnetic polarization (J,HJ(H) or amagnetization (M,HM(H) hysteresis loop and will always be numerically larger than the coercive field strength (HcB) measured from a magnetic fluxdensity (B,HB(H) hysteresis loop.DISCUSSIONThe intrinsic coercive field strength is not completely descri
46、bed without knowing the maximum magnetic polarization, maximum magnetization ormaximum magnetic field strength (Hm) used in the measurement.coercivitysee coercive field strength.coercivity, intrinsicsee coercive field strength, intrinsic.A340 185core, laminateda magnetic component constructed by sta
47、cking suitably thin pieces of magnetic material which are stamped,sheared, or milled from sheet or strip material. Individual pieces usually have an insulating surface coating to minimize eddycurrent losses in the assembled core.core, matedtwo or more magnetic core segments assembled with the magnet
48、ic flux path perpendicular to the mating surface.core, powder(dust)a magnetic core comprised of small particles of electrically insulated metallic ferromagnetic material. Thesecores are characterized by low hysteresis and eddy current losses.core, tape-wounda magnetic component constructed by the sp
49、iral winding of strip material onto a suitable mandrel. The stripmaterial usually has an insulating surface coating which reduces interlaminar eddy current losses in the finished core.core loss, ac eddy current, incremental, Pethe power loss caused by eddy currents in a magnetic material that is cyclicallymagnetized.core loss, ac eddy current, normal, Pethe power losses as a result of eddy currents in a magnetic material that issymetr
