1、Designation: A340 16Standard 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 revision. A
2、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, an attempt has been made to avoid, where possible, vectoranalysis and differential equations so as
3、 to make the definitions more intelligible to the average workerin the field of magnetic testing. In some cases, rigorous treatment has been sacrificed to securesimplicity, but it is believed that none of the definitions will prove to be misleading.It is the intent of this glossary to be consistent
4、in the use of symbols and units with those found inANSI/IEEE 260-1978 and USA Standard Y 10.5-1968.Part 1Symbols Used in Magnetic TestingSymbol Term cross-sectional area of B coilA cross-sectional area of specimenA solid areaBHmagnetic flux densitymagnetic inductionB excursion range of inductionBb b
5、iased inductionBdremanent inductionBdmremanenceBdHdenergy product(BdHd)mmaximum energy productBincremental inductionBiintrinsic inductionBmmaximum induction in a hysteresis loopBmaxmaximum induction in a flux current loopBrresidual inductionBrsretentivityBssaturation inductioncf crest factorCM cycli
6、cally magnetized conditiond lamination thicknessDBdemagnetizing coefficientdf distortion factorDmmagnetic dissipation factorE exciting voltageE1induced primary voltageE2induced secondary voltageEfflux voltsf cyclic frequency in hertz magnetomotive forceff form factorH magnetic field strengthH excurs
7、ion range of magnetic field strengthHbbiasing magnetic field strengthHcBcoercive field strengthHcJintrinsic coercive field strengthHddemagnetizing field strengthHincremental magnetic field strengthHgair gap magnetic field strengthHLac magnetic field strength (from an assumedpeak value of magnetizing
8、 currentHmmaximum magnetic field strength in a hyster-esis loopHmaxmaximum magnetic field strength in a flux-current loopHpac magnetic field strength (from a measuredpeak value of exciting current)Htinstantaneous magnetic field strength (coinci-dent with Bmax)Hzac magnetic field strength force (from
9、 an as-sumed peak value of exciting current)I ac exciting current (rms value)Icac core loss current (rms value)Idcconstant currentImac magnetizing current (rms value)J magnetic polarizationk coupling coefficient! flux path length!1effective flux path length!ggap length+ (also N ) flux linkage+mmutua
10、l flux linkage1This terminology is under the jurisdiction of ASTM Committee A06 onMagnetic Properties and is the direct responsibility of Subcommittee A06.92 onTerminology and Definitions.Current edition approved May 1, 2016. Published May 2016. Originallyapproved in 1949. Last previous edition appr
11、oved in 2015 as A340 15. DOI:10.1520/A0340-16.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1L self inductanceL1core inductanceLincremental inductanceLiintrinsic inductanceLmmutual inductanceL0initial inductanceLsseries inductanceLww
12、inding inductancem magnetic momentM magnetizationm total mass of a specimenm1active mass of a specimenNDdemagnetizing factorN1turns in a primary windingN2turns in a secondary windingN1I/!1ac excitationp magnetic pole strength3 permeanceP active (real) powerPaapparent powerPa (B;f)specific apparent p
13、owerPctotal core lossPc (B;f)specific core lossPcincremental core lossPenormal eddy current core lossPeincremental eddy current core lossPhnormal hysteresis core lossPhincremental hysteresis core lossPqreactive (quadrature) powerPrresidual core lossPwwinding loss (copper loss)Pzexciting powerPz (B;f
14、)specific exciting powerQmmagnetic storage factor5 reluctanceR1core resistanceRwwinding resistanceS lamination factor (stacking factor)SCM symmetrically cyclically magnetized conditionTcCurie temperaturew lamination widthWhhysteresis loop losslinear expansion, coefficient (average) incremental toler
15、ance hysteretic angle loss anglecos magnetic power factorpproton gyromagnetic ratio0magnetic constant density susceptibilityac Permeabilities:aideal permeabilityLinductance permeabilityL incremental inductance permeability0dinitial dynamic permeabilityppeak permeabilitypincremental peak permeability
16、iinstantaneous permeabilityzimpedance permeabilityzincremental impedance permeabilitydc Permeabilities: normal permeabilityabsabsolute permeabilityddifferential permeabilityincremental permeabilityeffeffective circuit permeabilityiincremental intrinsic permeabilitymmaximum permeabilityiinitial perme
17、abilityrrelative permeabilityvspace permeabilityrevreversible permeability/cot figure of merit reluctivity the numeric 3.1416 resistivity magnetic fluxN flux linkage (see +) mass susceptibility0initial susceptibility angular frequency in radians per secondPart 2Definition of Terms Used in Magnetic T
18、estingac excitation, N1I/1the ratio of the rms ampere-turns ofexciting current in the primary winding of an inductor to theeffective flux path length of the inductor.active (real) power, Pthe product of the rms current, I,inanelectrical circuit, the rms voltage, E, across the circuit, andthe cosine
19、of the angular phase difference, between thecurrent and the voltage.P 5 EI cosDISCUSSIONThe portion of the active power that is expended in amagnetic core is the total core loss, Pc.aging coefficientthe percentage change in a specific mag-netic property resulting from a specific aging treatment.DISC
20、USSIONThe aging treatments usually specified are:(a) 100 h at 150C or(b) 600 h at 100C.aging, magneticthe change in the magnetic properties of amaterial resulting from metallurgic change due to a normalor specified aging condition.DISCUSSIONThis term implies a deterioration of the magneticproperties
21、 of magnetic materials for electronic and electricalapplications, unless otherwise specified.air-gap magnetic field strength, Hgthe magnetic fieldstrength required to produce the induction existing at somepoint in a nonmagnetic gap in a magnetic circuit.DISCUSSIONIn the cgs-emu system of units, Hgis
22、 numerically equalto the induction existing at such a point and exceeds the magnetic fieldstrength in the magnetic material.amorphous alloya semiprocessed alloy produced by a rapidquenching, direct casting process resulting in metals withnoncrystalline structure.ampere (turn), Athe unit of magnetomo
23、tive force in the SIsystem of units. The symbol A represents the unit of electriccurrent, ampere, in the SI system of units.ampere per metre, A/mthe unit of magnetic field strength inthe SI system of units.anisotropic materiala material in which the magnetic prop-erties differ in various directions.
24、anisotropy of lossthe ratio of the specific core loss measuredwith flux parallel to the rolling direction to the specific coreloss with flux perpendicular to the rolling direction.A340 162anisotropy of loss 5Pc B;f! lPc B;f! twhere:Pc (B;f) l= specific core loss value with flux parallel to therollin
25、g direction, W/lb W/kg, andPc (B;f) t= specific core loss value with flux perpendicular tothe rolling direction, W/lb W/kg.DISCUSSIONThis definition of anisotropy normally applies to elec-trical steels with measurements made in an Epstein frame at a fluxdensity of 15 kG 1.5 T and a frequency of 60 H
26、z (see Test MethodA343).anisotropy of permeabilitythe ratio of relative peak perme-ability measured with flux parallel to the rolling direction tothe relative peak permeability measured with flux perpen-dicular to the rolling direction.anisotropy of permeability 5prlprtwhere:prl= relative peak perme
27、ability value with flux parallel tothe rolling direction, andprt= relative peak permeability value with flux perpendicu-lar to the rolling direction.DISCUSSIONThis definition of anisotropy normally applies to elec-trical steels with measurements made in an Epstein frame at a fluxdensity of 15 kG 1.5
28、 T and a frequency of 60 Hz (see Test MethodA343).antiferromagnetic materiala feebly magnetic material inwhich almost equal magnetic moments are lined up antipar-allel to each other. Its susceptibility increases as the tem-perature is raised until a critical (Nel) temperature isreached; above this t
29、emperature the material becomes para-magnetic.apparent power, Pathe product (volt-amperes) of the rmsexciting current and the applied rms terminal voltage in anelectric circuit containing inductive impedance. The compo-nents of this impedance as a result of the winding will belinear, while the compo
30、nents as a result of the magnetic corewill be nonlinear. The unit of apparent power is the volt-ampere, VA.apparent power, specific, Pa(B;f)the value of the apparentpower divided by the active mass of the specimen, that is,volt-amperes per unit mass. The values of voltage andcurrent are those develo
31、ped at a maximum value of cycli-cally varying induction B and specified frequency f.area, Athe geometric cross-sectional area of a magnetic pathwhich is perpendicular to the direction of the induction.Bloch walla domain wall in which the magnetic moment atany point is substantially parallel to the w
32、all surface. Seealso domain wall.Bohr magnetona constant that is equal to the magneticmoment of an electron because of its spin. The value of theconstant is (9 274 078 1021erg/gauss or9 274 078 1024J/T).cgs-emu system of unitsthe system for measuring physicalquantities in which the base units are th
33、e centimetre, gram,and second, and the numerical value of the magneticconstant, 0, is unity.coercive field strength, HcBthe absolute value of the appliedmagnetic field strength (H) required to restore the magneticflux density (B) to zero.DISCUSSIONThe symbol Hchas historically been used to denote th
34、ecoercive field strength determined from a (B,H) loop. Further use of thissymbol in ASTM A06 standards is deprecated.DISCUSSIONThe coercive field strength monotonically increaseswith increasing maximum magnetic field strength (Hm) reaching amaximum or limiting value termed the coercivity. Unless it
35、is knownthat the material has been magnetized to saturation, the term coercivefield strength is preferred.DISCUSSIONThe coercive field strength is not completely describedwithout knowing the maximum magnetic flux density (Bm) or maxi-mum magnetic field strength (Hm) used in the measurement.coercive
36、field strength, intrinsic, HcJthe absolute value ofthe applied magnetic field strength (H) required to restoreeither the magnetic polarization (J) or magnetization (M)tozero.DISCUSSIONThe symbol Hcihas historically been used to denote theintrinsic coercive field strength determined from a (Bi,H) loo
37、p. Furtheruse of this symbol in ASTM A06 standards is deprecated.DISCUSSIONThe intrinsic coercive field strength monotonicallyincreases with increasing maximum magnetic field strength (Hm)reaching a maximum or limiting value termed the intrinsic coercivity.Unless it is known that the material has be
38、en magnetized to saturation,the term intrinsic coercive field strength is preferred.DISCUSSIONThe measured value of intrinsic coercive field strengthwill be the same whether it is measured from a magnetic polarization(J,H) or a magnetization (M,H) hysteresis loop and will always benumerically larger
39、 than the coercive field strength (HcB) measured froma magnetic flux density (B,H) hysteresis loop.DISCUSSIONThe intrinsic coercive field strength is not completelydescribed without knowing the maximum magnetic polarization, maxi-mum magnetization or maximum magnetic field strength (Hm) used inthe m
40、easurement.coercivitysee coercive field strength.coercivity, intrinsicsee coercive field strength, intrinsic.core, laminateda magnetic component constructed bystacking suitably thin pieces of magnetic material which arestamped, sheared, or milled from sheet or strip material.Individual pieces usuall
41、y have an insulating surface coatingto minimize eddy current losses in the assembled core.core, matedtwo or more magnetic core segments assembledwith the magnetic flux path perpendicular to the matingsurface.core, powder (dust)a magnetic core comprised of smallparticles of electrically insulated met
42、allic ferromagneticmaterial. These cores are characterized by low hysteresis andeddy current losses.core, tape-wounda magnetic component constructed by thespiral winding of strip material onto a suitable mandrel. TheA340 163strip material usually has an insulating surface coating whichreduces interl
43、aminar eddy current losses in the finished core.core loss, ac eddy current, incremental, Pethe power losscaused by eddy currents in a magnetic material that iscyclically magnetized.core loss, ac eddy current, normal, Pethe power losses asa result of eddy currents in a magnetic material that issymetr
44、ically cyclically magnetized.DISCUSSIONThe voltage is generally assumed to be across theparallel combination of core inductance, L1, and core resistance, R1.core loss, ac, incremental, Pcthe core loss in a magneticmaterial when the material is subjected simultaneously to adc biasing magnetizing forc
45、e and an alternating magnetizingforce.core loss, residual, Prthe portion of the core loss power, Pc,which is not attributed to hysteresis or eddy current lossesfrom classical assumptions.core loss, ac, specific, Pc(B;f)the active power (watts) ex-pended per unit mass of magnetic material in which th
46、ere isa cyclically varying induction of a specified maximum value,B, at a specified frequency, f.core loss, ac, (total), Pcthe active power (watts) expended ina magnetic circuit in which there is a cyclically alternatinginduction.DISCUSSIONMeasurements of core loss are normally made withsinusoidally
47、 alternating induction, or the results are corrected fordeviations from the sinusoidal condition.core loss densitythe active power (watts) expended in amagnetic core in which there is a cyclically varying induc-tion of a specified maximum value, B, at a specifiedfrequency, f, divided by the effectiv
48、e volume of the core.DISCUSSIONThis parameter is normally used only for non-laminatedcores such as ferrite and powdered cores.core platea generic term for any insulating material, formedmetallurigically or applied externally as a thin surfacecoating, on sheet or strip stock used in the construction
49、oflaminated and tape wound cores.coupling coefficient, kthe ratio of the mutual inductancebetween two windings and the geometric mean of theindividual self-inductances of the windings.crest factor, cfthe ratio of the maximum value of a periodi-cally alternating quantity to its rms value.DISCUSSIONFor a sinusoidal variation the crest factor is =2.Curie temperature, Tcthe temperature above which a fer-romagnetic or ferrimagnetic materia
