BS EN IEC 60404-7-2020 pdf download.Magnetic materials – Part 7: Method of measurement of the coercivity (up to 160 kA/m) of magnetic materials in an open magnetic circuit (IEC 60404-7:2019).
This part of IEC 60404 specifies a method of measurement of the coercivity of magnetic materials in an open magnetic circuit.
This document is applicable to all magnetic materials with coercivities from 0,2 A/m to 1 60 kA/m.
NOTE Examples of magnetic materials covered by this document are amorphous alloys, nanocrystalline alloys, all softmagnetic crystalline materials (e.g. Fe, FeSi-, CoFe- and FeNi-alloys), soft ferrites, hard metals, semi-hard magnetic alloys (e.g. FeCoTiAl-, FeCoV-, FeCrCo- and AlNiCo-alloys) [1 ] 1 .
Special precautions are to be taken in measuring coercivities below 40 A/m, in materials with high conductivity and in test specimens which have a shape different from ellipsoids (see Annex A).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
There are no normative references in this document.
3 Terms and definitions
For the purpose of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1 coercivity H cJ
value of the coercive field strength in a material when the magnetic flux density, magnetic polarization or magnetization is brought from saturation by a monotonically changing magnetic field to zero
Note 1 to entry: The parameter that is varied should be stated, and the appropriate symbol used as follows: H cB for the coercivity relating to the magnetic flux density, H cJ for the coercivity relating to the magnetic polarization,H cM for the coercivity relating to the magnetization. The first two symbols supersede H cB and H cJ respectively.
3.2 demagnetize
to reduce the magnetic flux density of a magnetized material along the demagnetization curve
Note 1 to entry: The coercivities H cB and H cJ are respectively discriminated depending on the hysteresis loop being defined in the B = f(H) or J = f(H) system (see Figure 1 ). It can be shown that, for materials of high-differential permeability in the region B = 0, the difference between the coercivity H cJ and the coercivity H cB is negligible since:
where
H cB coercivity relating to the magnetic flux density, in amperes per metre;
H cJ coercivity relating to the magnetic polarization, in amperes per metre;
ΔB incremental change in magnetic flux density (at B = 0), in teslas;
ΔH corresponding change in magnetic field strength, in amperes per metre;
µ o magnetic constant (4π x 1 0 -7 in henrys per metre).BS EN IEC 60404-7 pdf download.