IEC 60404-7:2019

IEC 60404-7 ®
Edition 2.0 2019-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Magnetic materials –
Part 7: Method of measurement of the coercivity (up to 160 kA/m) of magnetic
materials in an open magnetic circuit

Matériaux magnétiques –
Partie 7: Méthode de mesure de la coercitivité (jusqu'à 160 kA/m) des matériaux
magnétiques en circuit magnétique ouvert

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IEC 60404-7 ®
Edition 2.0 2019-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Magnetic materials –
Part 7: Method of measurement of the coercivity (up to 160 kA/m) of magnetic

materials in an open magnetic circuit

Matériaux magnétiques –
Partie 7: Méthode de mesure de la coercitivité (jusqu'à 160 kA/m) des matériaux

magnétiques en circuit magnétique ouvert

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.030; 17.220.20 ISBN 978-2-8322-6385-3

– 2 – IEC 60404-7:2019 © IEC 2019
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle of the method . 7
5 Test specimen . 8
6 Solenoid . 8
7 Compensation for the earth’s magnetic field and static and dynamic magnetic
noise fields . 8
8 Magnetic shielding of the measurement region . 8
9 Measurement . 8
9.1 Magnetization . 8
9.2 Measuring methods . 9
9.2.1 General . 9
9.2.2 Method A . 9
9.2.3 Method B . 10
9.3 Determination of coercivity . 11
9.4 Reproducibility . 12
10 Test report . 13
Annex A (normative)  Precautions to be taken for measurements of coercivity below
40 A/m, with a complex shaped test specimen and some special cases . 14
A.1 Coercivity below 40 A/m . 14
A.2 Coercivity measurement of test specimens with complex shapes . 14
A.3 Optimization of the amplitude and time of the magnetizing cycle for a test
specimen of soft magnetic material . 14
A.4 Mechanical stress and heating of the test specimen in the solenoid . 14
Annex B (informative) Method C with a VSM (Vibrating Sample Magnetometer) . 15
Bibliography . 17

Figure 1 – Demagnetizing B(H) and J(H) curves from saturation . 6
Figure 2 – Circuit diagram for Methods A and B . 7
Figure 3 – Method A, magnetic flux sensing probe: Hall probe . 9
Figure 4 – Method A, magnetic flux sensing probe: differential fluxgate probe . 10
Figure 5 – Method B, magnetic flux sensing probe: differential fluxgate probe . 11
Figure 6 – Magnetic polarisation J over the length L of a cylindrical rod . 12
Figure B.1 – Schematic diagram of Method C with a VSM . 15

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MAGNETIC MATERIALS –
Part 7: Method of measurement of the coercivity (up to 160 kA/m) of
magnetic materials in an open magnetic circuit

FOREWORD
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International Standard IEC 60404-9 has been prepared by IEC technical committee 68:
Magnetic alloys and steels.
This second edition cancels and replaces the first published in 1982. This edition constitutes
a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Clause 1: The scope includes a more detailed description of the magnetic materials which
applies to this standard;
b) Clause 4: Figure 2 – circuit diagram for methods A and B was simplified and the fluxgate
probes inside the solenoid have been added;
c) Clause 7: Compensation for the earth’s magnetic field and for static and dynamic
magnetic noise fields has been added;

– 4 – IEC 60404-7:2019 © IEC 2019
d) Clause 8: Magnetic shielding of the measuring region has been added;
e) 9.2.2: The measuring methods for local and integral measurement of the flux in the test
specimen hav
...