IEC 60404-2:1996/AMD1:2008

Amendment 1 - Magnetic materials - Part 2: Methods of measurement of magnetic properties of electrical steel strip and sheet by means of an Epstein frame

The contents of the corrigendum of March 2018 have been included in this copy.

Amendement 1 - Matériaux magnétiques - Partie 2: Méthodes de mesure des propriétés magnétiques des bandes et tôles magnétiques en acier au moyen d'un cadre Epstein

Le contenu du corrigendum de mars 2018 a été pris en considération dans cet exemplaire.

General Information

• Status: Published
• Publication Date: 28-Apr-2008
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 17.220.20 - Measurement of electrical and magnetic quantities
• ICS: 29.030 - Magnetic materials
• Technical Committee: TC 68 - Magnetic alloys and steels
• Drafting Committee: WG 2 - TC 68/WG 2
• Current Stage: PPUB - Publication issued
• Start Date: 31-May-2008
• Completion Date: 29-Apr-2008

Relations

• Amends: IEC 60404-2:1996 - Magnetic materials - Part 2: Methods of measurement of the magneticproperties of electrical steel sheet and strip by means of anEpstein frame
• Effective Date: 05-Sep-2023
• Corrected By: IEC 60404-2:1996/AMD1:2008/COR1:2018 - Corrigendum 1 - Amendment 1 - Magnetic materials - Part 2: Methods of measurement of magnetic properties of electrical steel strip and sheet by means of an Epstein frame
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60404-2
Edition 3.0 2008-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
AMENDMENT 1
AMENDEMENT 1
Magnetic materials –
Part 2: Methods of measurement of magnetic properties of electrical steel strip
and sheet by means of an Epstein frame

Matériaux magnétiques –
Partie 2: Méthodes de mesure des propriétés magnétiques des bandes et tôles
magnétiques en acier au moyen d'un cadre Epstein

IEC 60404-2 A1:2008
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IEC 60404-2
Edition 3.0 2008-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
AMENDMENT 1
AMENDEMENT 1
Magnetic materials –
Part 2: Methods of measurement of magnetic properties of electrical steel strip
and sheet by means of an Epstein frame

Matériaux magnétiques –
Partie 2: Méthodes de mesure des propriétés magnétiques des bandes et tôles
magnétiques en acier au moyen d'un cadre Epstein

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
G
CODE PRIX
ICS 29.030; 17.220.20 ISBN 2-8318-9724-6

– 2 – 60404-2 Amend. 1  IEC:2008
FOREWORD
This amendment has been prepared by IEC technical committee 68: Magnetic alloys and steels.
The text of this amendment is based on the following documents:
FDIS Report on voting
68/365/FDIS 68/369/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the maintenance result date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
The contents of the corrigendum of March 2018 have been included in this copy.
_____________
Title
In the title of the standard, replace “steel sheet and strip” with “steel strip and sheet”:

Page 7
2 Normative references
Replace the introductory paragraph and the existing references by the following:
The following referenced documents are indispensable for the application 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.
IEC 60050-221, International Electrotechnical Vocabulary – Chapter 221: Magnetic materials
and components
IEC 60404-4, Magnetic materials – Part 4: Methods of measurement of d.c. magnetic
properties of magnetically soft materials
IEC 60404-8-3, Magnetic materials – Part 8-3: Specifications for individual materials – Cold-
rolled electrical non-alloyed and alloyed steel sheet and strip delivered in the semi-processed
state
IEC 60404-8-4, Magnetic materials – Part 8-4: Specifications for individual materials – Cold-
rolled non-oriented electrical steel sheet and strip delivered in the fully-processed state

60404-2 Amend. 1  IEC:2008 – 3 –
IEC 60404-8-7, Magnetic materials – Part 8-7: Specifications for individual materials – Cold-
rolled grain-oriented electrical steel sheet and strip delivered in the fully-processed state
IEC 60404-10, Magnetic materials – Part 10: Methods of measurement of magnetic properties
of magnetic sheet and strip at medium frequencies
IEC 60404-13, Magnetic materials – Part 13: Methods of measurement of density, resistivity
and stacking factor of electrical steel sheet and strip

Page 15
3.6 Voltage measurement
Introduce, after the existing paragraph, and before 3.6.1, the following note:
NOTE For the application of digital sampling methods, see Annex A.

3.7 Frequency measurement
Introduce, after the existing paragraph, the following note:
NOTE For the application of digital sampling methods, see Annex A.

3.8 Power measurement
Introduce, after the first paragraph, the following note:
NOTE For the application of digital sampling methods, see Annex A.

4 Procedure for the measurement of the specific total loss
Introduce, after the clause heading, the following note:
NOTE For the application of digital sampling methods, see Annex A.

– 4 – 60404-2 Amend. 1  IEC:2008
Page 37
Add, after the figures, the following new Annex A:
Annex A
(informative)
Digital sampling methods for the determination of the magnetic properties

A.1 General
The digital sampling method is an advanced technique that is becoming almost exclusively
applied to the electrical part of the measurement procedure of this standard. It is
characterized by the digitalization of the secondary voltage, U (t), and the voltage drop
across the non-inductive precision resistor in series with the primary winding (see Figure 5),
U (t), and the evaluation of the data for the determination of the magnetic properties of the

test specimen. For this purpose, instantaneous values of these voltages having index j, u
2j
and u respectively, are sampled and held simultaneously from the time-dependent voltage

1j
functions during a narrow and equidistant time period each by sample-and-hold circuits. They
are then immediately converted to digital values by analog-to-digital converters (ADC). The
data pairs sampled over one or more periods together with the specimen and the set-up
parameters provide complete information for one measurement. This data set enables
computer processing for the determination of all magnetic properties required in this standard.
The digital sampling method may be applied to the measurement procedures which are
described in the main part of this standard. The block diagram in Figure 3 applies equally to
the analogue and the digital sampling method. The digital sampling method allows all
functions of the measurement equipments in Figure 3 to 8 to be realized by a combined
system of data acquisition equipment and software. The control of the sinusoidal waveform of
the secondary voltage can also be realized by a digital method. However, the purpose and
procedure of that technique are different from those of this annex and are not treated here.

More information can be found in [1] and [2].
This annex is helpful in understanding the impact of the digital sampling method on the
precision achievable by the methods of this standard. This is particularly important because
ADC circuits, transient recorders and supporting software are easily available, thus
encouraging one to build one’s own wattmeter. The digital sampling method can offer low
uncertainty, but it leads to large errors if improperly used.
A.2 Technical details and requirements
The principle of the digital sampling method is the discretization of voltage and time, i.e. the
replacement of the infinitesimal time interval dt by the finite time interval ∆t :
___________
The figures in brackets refer to the Bibliography.

60404-2 Amend. 1  IEC:2008 – 5 –
T 1 1
(A.1)
∆t= = =
n fn f
s
where
∆t is the time interval between the sampling points, in seconds;
T is the length of the magnetizing period, in seconds;
n is the number of instantaneous values sampled over one period;
f  is the magnetizing frequency, in hertz;
f is the sampling frequency, in points per seconds.

s
In order to achieve lower uncertainties, the length of the magnetizing period divided by the
time interval between the sampling points, i.e. the ratio f /f, should be an integer (Nyquist
s
condition [5]) and the sampling frequency, f , should be greater than twice the input signal
s
bandwidth.
According to an average-sensing voltmeter, the peak value of the flux density can be
calculated by the sum of the u values sampled over one period as follows:
2j
T
n−1
1 1 1
ˆ
(A.2)
J= U (t)dt≅ u
2 ∑ 2 j
∫
4fN A T 4f N A
j=0
2 t=0 s 2
The calculation of the specific total loss is carried out by point-by-point multiplication of the u
2j
)
and u values and summation over one period as follows :
1j
~
T 2
n−1 n−1
   
1 N 1 U 1 N 1 1 1
1 2 1
 
     (A.3)
P= U (t)U (t)dt− ≅ u u − u
∑ ∑
s 1 2 1j 2j 2j
∫
   
l Aρ RN T R l Aρ RN n R n
m m 2 i m m 2 j=0 i j=0
 t=0   
where
ˆ
J is the peak value of the magnetic polarization, in teslas;
P is the specific total loss of the specimen, in watts per kilogram;
s
T is the length of the magnetization period, in seconds;
N is the number of instantaneous values sampled over one period;
f is the magnetizing frequency, in hertz;
f is the sampling frequency, in points per second;

s
N is the number of turns of the primary winding;
N is the number of turns of the secondary winding;
A is the cross-sectional area of the test specimen, in square metres;
R is the resistance of the non-inductive precision resistor R in series with the primary
winding (see Figure 5), in ohms;
___________
)
The peak value of the magnetic field strength and the apparent power can be calculated correspondingly by
using
n n
N N 1 1
2 2
1  and 1
ˆ ˆ
H= U S ≅ u u
1 s ∑ 1j ∑ 2 j
Rl l RN Aρ n n
m j=0 j=0
m 2 m
– 6 – 60404-2 Amend. 1  IEC:2008
R is the combined equivalent resistance of the instruments in the secondary circuit, in
i
ohms;
u is the voltage drop across the non-inductive precision resistor R, in volts;
u is the secondary voltage, in volts;
~
U is the r.m.s. value of the voltage induced in the secondary winding, in volts.
j is the running number of instantaneous values;
I is the conventional effective magnetic path length, in metres (I = 0,94 m);
m m
ρ is the conventional density of the test material, in kilograms per cubic metre.
m
The pairs of values, u and u , can then be processed by a computer or, for real time
2j 1j
processing, by a digital signal processor (DSP) using a sufficiently fast digital multiplier and
adder without intermediate storage being required. Keeping the Nyquist condition is possible
only where the sampling frequency f and the magnetizing frequency f are derived from a
s
common high frequency clock and thus have an integer ratio f /f. In that case, magnetization
s
waveforms may be scanned using 128 samples per period with sufficient accuracy. This
...