IEC 60404-3:1992+AMD1:2002+AMD2:2009 CSV

Magnetic materials - Part 3: Methods of measurement of the magnetic properties of electrical steel strip and sheet by means of a single sheet tester

IEC 60404-3:1992+A1:2002+A2:2009 defines the general principles and the technical details of the measurement of the magnetic properties of magnetic sheets, at power frequencies, by means of a single sheet tester. This tester is applicable to flat plate specimens obtained from magnetic sheets and strips of any quality. The magnetic characterictics are determined for a sinusoidal induced voltage, for specified peak values of magnetic polarization and for a specified frequency.  This consolidated version consists of the second edition (1992), its amendment 1 (2002), its amendment 2 (2009) and its corrigendum (2009). Therefore, no need to order amendments in addition to this publication.

Matériaux magnétiques - Partie 3: Méthodes de mesure des caractéristiques magnétiques des bandes et tôles magnétiques en acier à l'aide de l'essai sur tôle unique

La CEI 60404-3:1992+A1:2002+A2:2009 définie les principes généraux et les détails techniques de mesure des propriétés magnétiques des tôles magnétiques, à fréquences industrielles, à l'aide de l'essai sur tôle unique. L'essai sur tôle unique est applicable à des échantillons prélevés dans les tôles et feuillards magnétiques de toute qualité. Les caractéristiques magnétiques sont déterminées pour une tension induite sinusoïdale, pour des valeurs de crête spécifiées de la polarisation magnétique et pour une fréquence spécifiée.  Cette version consolidée comprend comprend la deuxième édition (1992), son amendement 1 (2002), son amendement 2 (2009) et le corrigendum de décembre 2009. Il n'est donc pas nécessaire de commander les amendements avec cette publication.

Field acceptance tests to determine the hydraulic performance of hydraulic turbines, storage pumps and pump turbines

General Information

• Status: Published
• Publication Date: 20-Apr-2010
• ICS: 17.220.20 - Measurement of electrical and magnetic quantities
• ICS: 27.140 - Hydraulic energy engineering
• ICS: 29.030 - Magnetic materials
• Technical Committee: TC 68 - Magnetic alloys and steels
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 08-Nov-2022
• Ref Project: SIST IEC 60041:1999 - Field acceptance tests to determine the hydraulic performance of hydraulic turbines, storage pumps and pump-turbines

Overview

IEC 60404-3:1992+AMD1:2002+AMD2:2009 CSV - "Magnetic materials - Part 3: Methods of measurement of the magnetic properties of electrical steel strip and sheet by means of a single sheet tester" - defines the fundamental principles and technical requirements for measuring the magnetic properties of electrical steel using a single sheet tester. This consolidated edition (second edition plus Amendments 1 & 2 and corrigendum) provides a complete, up-to-date reference for laboratory and production testing without ordering separate amendments. The standard covers measurements at power frequencies for flat plate specimens cut from magnetic sheet or strip and specifies conditions for sinusoidal excitation, peak magnetic polarization, and test frequency.

Key Topics

• Scope and applicability: Measurement methods for magnetic sheets and strips of any quality using a single sheet tester.
• Test conditions: Procedures for applying a sinusoidal induced voltage and controlling specified peak values of magnetic polarization at power frequencies.
• Specimen preparation: Use of flat plate specimens obtained from electrical steel strip and sheet (requirements for specimen geometry and handling are addressed in the standard).
• Measurement principles: Determination of magnetic characteristics (hysteresis, permeability-related parameters) under standardized excitation and frequency conditions.
• Technical details and repeatability: Requirements that ensure consistent, comparable results across labs and production facilities - including instrumentation, calibration, and data reporting practices.

Applications

IEC 60404-3 is essential for organizations involved in the selection, production, testing, and research of electrical steel and magnetic materials:

• Material manufacturers use it for quality control and specification compliance of electrical steel strip and sheet.
• Transformer and motor designers rely on standardized magnetic property data to select core materials and predict core losses at power frequencies.
• Independent test laboratories implement the methods to provide certified magnetic property measurements and comparisons.
• R&D teams apply the standard when developing new magnetic alloys or evaluating processing effects (annealing, coating, rolling).

Using this standard helps ensure reliable, comparable magnetic property data, which is critical for efficiency optimization and loss estimation in electrical machines and power conversion equipment.

Related Standards

• Other parts of the IEC 60404 series covering magnetic materials and measurement methods.
• National and international standards for electromagnetic materials testing and core-loss measurement.

Keywords: IEC 60404-3, magnetic materials, electrical steel, single sheet tester, magnetic properties measurement, power frequency, magnetic polarization, sinusoidal induced voltage.

Standards Content (Sample)

SLOVENSKI STANDARD
01-april-1999
Field acceptance tests to determine the hydraulic performance of hydraulic
turbines, storage pumps and pump turbines
Field acceptance tests to determine the hydraulic performance of hydraulic turbines,
storage pumps and pump-turbines
Essais de réception sur place des turbines hydrauliques, pompes d'accumulation et
pompes-turbines, en vue de la détermination de leurs performances hydrauliques
Ta slovenski standard je istoveten z: IEC 60041
ICS:
27.140 Vodna energija Hydraulic energy engineering
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

NORME CEI
INTERNATIONALE IEC
INTERNATIONAL
Troisième édition
STANDARD
Third edition
1991-11
Essais de réception sur place des turbines
hydrauliques, pompes d'accumulation et
pompes-turbines, en vue de la détermination
de leurs performances hydrauliques
Field acceptance tests to determine the
hydraulic performance of hydraulic turbines,
storage pumps and pump-turbines
© CEI 1991 Droits de reproduction réservés — Copyright — all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun pro- any form or by any means, electronic or mechanical,
cédé, électronique ou mécanique, y compris la photocopie et including photocopying and microfilm, without permission
les microfilms, sans l'accord écrit de l'éditeur. in writing from the publisher.
Genève, Suisse
Bureau Central de la Commission Electrotechnique Internationale 3, rue de Varembé
Commission Electrotechnique Internationale CODE PRIX
International Electrotechnical Commission PRICE CODE
Mert+uuyttapoatiaa 3netcrporexHHVecnan liornt+cct+a
IEC
el Pour prix, voir catalogue en vigueur
•
For price, see current catalogue

Publication 41 de la CEI IEC Publication 41
(Troisième édition – 1991) (Third edition – 1991)
Essais de réception sur place des turbines Field acceptance tests to determine
hydrauliques, pompes d’accumulation et the hydraulic performance of
pompes-turbines, hydraulic turbines, storage pumps and
en vue de la détermination pump-turbines
de leurs performances hydrauliques
CORRIGENDUM 1
Correction dans le texte anglais uniquement Page 3
CONTENTS
In the title of subclause 4. 1, instead of
. . . provision for the test . . .
read
. . . provision for test . . .
Page 13
Correction dans le texte anglais uniquement
In clause 1, Scope and object, change the
numeration in order to obtain (as on page 12):
Scope and object
1.1 Scope
1.1.1 This International Standard . . .
1.1.2 Model tests, when used . . .
1.1.3 Tests of speed . . .
1.2 Object
1.3 Types of machines
Page 17
Page 16
In the table, subclause 2.3.1.7 (Limits), replace the
Dans le tableau, au paragraphe 2.3.1.7 (Limites),
existing symbols by the following new symbols:
remplacer les signes représentatifs existants par
les nouveaux signes suivants:
. . . not to be exceeded
. . . à pas dépasser
ne
. . . to be reached
. . . à atteindre
Correction dans le texte anglais uniquement Page 29
In the table, subclause 2.3.6.4, third column, in the
sixth line, instead of
g +g
... and g =
read
+ g
g
... and g =
Page 30
Dans le tableau, au paragraphe 2.3.6.5, sous Correction in the French text only.
«Terme» (deuxième colonne), au lieu de
. . . . pompe à débit
lire
. . . . pompe à débit nul
Page 34, figure 5b
Page 35, figure 5b
Dans la partie supérieure du schéma, déplacer les In the upper part of the diagram, rearrange the two
existing equations so as to place them together, on
deux équations existantes afin de les situer ensemble
à droite, au-dessus du schéma décrivant un «Groupe the right-hand side, above the diagram describing a
à axe horizontal», comme suit: “Horizontal shaft unit” as follows:
Z 1
Z = z 1´ – z = z z
1´ – 1
1 1
Z2 = z2´ – z
Z = z z
2 2´ – 2 2
Page 36, figure 5c Page 37, figure 5c
Dans la bordure de droite du schéma, à la hauteur Add, at the right-hand side of the diagram, level
de la pointe de flèche, ajouter l’équation suivante: with the arrowhead, the following equation:
z z z z
1 = 2 1 = 2
Page 84, figure 14 Correction in the French text only
Dans le schéma, au lieu de «constant», lire partout
«constante».
Page 86 Correction in the French text only
6.2.3.2 Erreurs aléatoires
Dans l’avant-dernière ligne de la page, au lieu de
. . . dépend de la combinaison des lectures et de
la combinaison de l’erreur aléatoire . . .
lire
. . . dépend de la combinaison de l’erreur
aléatoire . . .
Page 128
Page 129
10.2.3.2 Prescriptions complémentaires
10.2.3.2 Additional requirements
Au cinquième alinéa, au lieu de
In the fifth paragraph, instead of
Annexes F et G de l’ISO 3354:
Annexes F and G of ISO 3354:
lire
read
Annexes H et J de l’ISO 3354:
Annexes H and J of ISO 3354:
Correction dans le texte anglais uniquement
Page 141
10.2.5.6 Computation of discharge
In the eighth line of text, instead of
m is the coefficient . . .
read
m is a coefficient . . .
Correction dans le texte anglais uniquement Page 195, figure 34b
In the legends below the diagram, on the right-hand
side; in the first line, instead of
. . . (geodesic . . .
read
. . . (geodetic . . .
third line, instead of
z ´ = z ´ – z . . .
B B B
read
Z ´ = z ´ – z . . .
B B B
Page 204, figure 37 Page 205, figure 37
Même correction qu’en page 34 (voir ci-dessus) Same correction as on page 35 (see above)
Page 206, figure 38 Page 207, figure 38
Même correction qu’en page 36 (voir ci-dessus) Same correction as on page 37 (see above)
Page 212 Page 213
Dans l’équation encadrée au haut de la page, après In the framed equation at the top of the page, after
le H, ajouter un signe égal (=); au lieu de the H add an equal sign (=); instead of
(p p
absl − abs 2 )
(vi − v
z )
E = g ⋅ H +  g ⋅ (z − z )
1 2
lire read
(p p
abs1 − abs 2 )
(vi − v Z )
E = g ⋅ H = +  g ⋅ (z − z )
1 2
Page 214 Page 215
l’équation située juste au-
Dans dessous de la In the equation following figure 41, instead of
figure 41 au lieu de
(p − p
,^)
abs
v
2 2
NPSE = g ⋅ NPSH = + g ⋅ (z − z )
+
2 2 r 2
ρ 2
lire read
(p − p
,^)
abs
v
2 2
NPSE NPSH − − z
= g ⋅ = g (z )
+
2 2 U 2
⋅
ρ 2
Correction dans le texte anglais uniquement Page 219, figure 42
In the legends under the diagram, instead of
d = 3 mm à 6 mm
read
d = 3 mm to 6 mm
Page 228, figure 45a Page 229, figure 45a
In the third line of the legends half-way up the
diagram, instead of
Δp = differential-pressure
read
Δp = differential pressure
Under the diagram, in the formula for p , delete
Sous le schéma, dans la formule pour p enlever M
M
one Δ in order to read:
un Δ afin de lire:
p = p + ρ g h = p + ρ g (h – h ) + ρ ⋅ g ⋅ h + Δp
⋅ ⋅ ⋅ ⋅
M 1 1 oil 2 1 1
Page 256 Page 257
Sous l’équation (4), dans la dernière formule de Under equation (4), in the last formula on the
la page, aligner les indices; au lieu de page, align indices; instead of
P (2w) P (2w)
COS ϕ = cos ϕ =
UU
s s
A3⋅ U ⋅ I 3⋅ U ⋅ I
s s s s
lire read
P P
as(2w) as(2w)
COS ϕ = cos ϕ
s s
U ⋅ I 9 3⋅ U ⋅ I
s s s s
Page 280 Correction in the French text only
Dans la légende de la figure 58, au lieu de
– Dimension du bâti . . .
lire
– Dimensions du bâti . . .
Correction dans le texte anglais uniquement
Page 303
In the penultimate line of the page:
instead of “ou”, read “or”.
Correction in the French text only
Page 308
14.4.2 Mesures auxiliaires
Dans la première ligne, au lieu de
. . . à ±5 % près, . . .
lire
. . . à ±5 % près environ, . . .

Page 322 Page 323
Paragraphe 15.2.1.1, deuxième alinéa, dernière Subclause 15.2.1.1, second paragraph, last line,
ligne, au lieu de instead of
. . . n, théoriquement égale à . . . . . . n theoretically equal to . . .
lire read
. . . n est théoriquement égal à . . . . . . n is theoretically equal to . . .
Page 356 Page 357
Dans les première et troisième lignes du _texte In the first line and third line of text, just below
juste au-dessous du tableau C1, au lieu de « Y» et table C.1, instead of “Y ”and "Y r ” read Yr
«Y r
» lire Y
r
Correction in the French text only
Page 398
Annexe H
Dans le titre, à la deuxième ligne, au lieu de
. . . DE L’ÉNERGIE MÉCANIQUE
lire
DE L’ÉNERGIE MÉCANIQUE
. . .
MASSIQUE
Mars 1996 March 1996
41 © I E C - 3 -
CONTENTS
Page
FOREWORD 9
PREFACE 9
SECTION ONE - GENERAL RULES
Clause
1. Scope and object 13
1.1 Scope 13
1.2 Object 13
1.3 Types of machines 13
1.4 Reference to IEC and ISO standards 15
1.5 Excluded topics 15
2. Terms, definitions, symbols and units 15
2.1 General 15
2.2 Units 15
2.3 List of terms, definitions, symbols and units 15
3. Nature and extent of hydraulic performance guarantees 51
3.1 General 51
3.2 Main guarantees 51
3.3 Other guarantees 55
4. Organisation of test 59
4.1 Adequate provision for the test 59
4.2 Authority for test 59
4.3 Personnel 59
4.4 Preparation for test 59
4.5 Agreement on test procedure 61
4.6 Instruments 63
4.7 Observations 63
4.8 Inspection after test 65
4.9 Final report 67
SECTION Two- EXECUTION OF TEST FOR THE DETERMINATION
OF THE STEADY STATE PERFORMANCE OF THE MACH INE
5. Test conditions and procedure 71
5.1 General test procedure 71
5.2 Test conditions to be fulfilled
6. Computation and analysis of results 81
6.1 Computation of test results
6.2 Uncertainties in measurements and presentation of results 87
6.3 Comparison with guarantees 93
SECTION TI IREE - EXECUTION OF TEST FOR THE DETERMINATION
OF TRIE TRANSIENT CHARACTERISTIC OF THE MACHINE
7. Test conditions and procedure
7.1 Test conditions
trumentation 7.2 Test procedure and ins

41© IEC -5 -
Page
Clause
8. Computation and analysis of results
8.1 Conversion of results
8.2 Comparison with guarantees
SECTION FOUR - METHODS OF MEASUREMENT
9. Introduction 115
9.1 Efficiency
9.2 Hydraulic power
9.3 Mechanical power
10. Discharge
10.1 General
10.2 Current-meter method
10.3 Pitot tubes
10.4 Pressure-time method 147
10.5 Tracer methods 163
10.6 Weirs 167
10.7 Standardized differential pressure devices 179
10.8 Volumetric gauging method 181
11. 187
Specific hydraulic energy of the machine
11.1 General 187
11.2 Determination of the specific hydraulic energy 189
11.3 Determination of the net positive suction specific energy
11.4 Pressure measurements
11.5 Free water level measurements
11.6 Uncertainty of measurements 251
12. Power 253
12.1 Indirect method of power measurement 253
12.2 Direct method of power measurement 283
12.3 Bearing losses
13. Rotational speed
13.1 General
13.2 Speed measurements in the case of direct measurement of power
13.3 Speed measurements in the case of indirect measurement of power
13.4 Uncertainty of measurement
14. Thermodynamic method for measuring efficiency 293
14.1 General
14.2 Efficiency and specific mechanical energy
14.3 Procedure for measurement of specific mechanical energy
14.4 Apparatus
14.5 Test conditions to be fulfilled
14.6 Corrective terms
14.7 Uncertainty of measurement

41 © IEC 7
Page
Clause
15. Index tests
15.1 General 321
15.2 Relative discharge measurement
15.3 Measurement of other quantities 331
15.4 Computation of results 331
15.5 Uncertainty of measurement
APPEr\TDIX A — Systematic uncertainties in performance measurements at steady state conditions
APPENDIX B — Rejection of outliers
APPENDIX C — Analysis of the random uncertainties for a test at constant operating conditions
D — Analysis of the random uncertainties for a test over a range of operating conditions . 363
APPENDIX
APPENDIX E — Physical data
APPENDIX F — Derivation of the equation for the specific hydraulic energy of a machine
APPENDIX G — Measurement of electric power — Determination of the correction for a single-phase
measuring system
APPENDIX H — Thermodynamic method — Examples for a balance of power and computation of the
specific mechanical energy
APPENDIX J — Acoustic method of discharge measurement

41 © IEC — 9 —
INTERNATIONAL ELECTROTECHNICAL COMMISSION
FIELD ACCEPTANCE TESTS TO DETERMINE
THE HYDRAULIC PERFORMANCE OF HYDRAULIC TURBINES,
STORAGE PUMPS AND PUMP-TURBINES
FOREWORD
The formal decisions or agreements of the IEC on technical matters, prepared by Technical Committees on which all the National
1)
rnational consensus of opinion on the
Committees having a special interest therein are represented, express, as nearly as possible, an inte
subjects dealt with.
and they arc accepted by the National Committees in that sense.
2) They have the form of recommendations for international use
In order to promote international unification, the I E C expresses the wish that all National Committees should adopt the text of the I EC
3)
recommendation for their national rules in so far as national conditions will permit. Any divergence between the I E C recommendation
and the corresponding national rules should, as far as possible, be clearly indicated in the latter.
PREFACE
This International Standard has been prepared by IEC Technical Committee No. 4: Hydraulic turbines.
It replaces the second edition of IEC 41, the first edition of IEC 198 and the first edition of IEC 607.
The text of this standard is based on the following documents:
Report on Voting
Six Months' Rule
4 (CO) 52
4 (CO) 48
Full information on the voting for the approval of this standard can be found in the Voting Report indicated in
the above table.
The following IEC publications are quoted in this standard:
Publications Nos. 34-2 (1972): Rotating electrical machines. Pa rt 2: Methods for determining losses and efficiency of rotating
electrical machinery from tests (excluding machines for traction vehicles).
34-2A (1974): First supplement: Measurement of losses by the calorimetric method.
185 (1987): Current transformers.
186 (1987): Voltage transformers.
Amendment No.1 (1988).
(1965): International code for model acceptance tests of hydraulic turbines.
Amendment No.1 (1977).
193A (1972): First supplement.
(1970): International code for testing of speed governing systems for hydraulic turbines.
(1976): International code for model acceptance tests of storage pumps.
(1976): Guide for commissioning, operation and maintenance of hydraulic turbines.
(1978): Cavitation pitting evaluation in hydraulic turbines, storage pumps and pump-turbines.
ce of storage pumps and of pump-turbines
(1985): Guide for commissioning, operation and mainten an
operating as pumps.
41© IEC - 11 —
ISO standards quoted:
Publications Nos. 31-3 (1978): Quantities and units of mechanics. Amendment 01-1985.
748 (1979): Liquid flow measurements in open channels – Velocity-area methods.
1438-1 (1980): Water flow measurement in open channels using weirs and Ventu ri flumes-Part 1: Thin-plate
weirs.
2186 (1973): Fluid flow in closed conduits – Connections for pressure signal tr ansmissions between primary
d
an secondary elements.
2533 (1975): Standard Atmosphere. Addendum 01-1985.
2537 (1988): Liquid flow measurement in open channels –Rotating element current-meters.
2975: Measurement of water flow in closed conduits – Tracer methods.
2975-1 (1974): Part I: General.
2975-2 (1975): Part II: Constant rate injection method using non-radioactive tracers.
III: Constant rate injection method using radioactive tracers.
2975-3 (1976): Pa rt
2975-6 (1977): Pa rt VI: Transit time method using non-radioactive tracers.
2975-7 (1977): Part VII: Transit time method using radioactive tracers.
3354 (1988): Measurement of clean water flow in closed conduits – Velocity area method using current-meters
in full conduits and under regular flow condi tions.
3455 (1976): Liquid flow measurement in open channels – Calibration of rotating-element current-meters in
straight open tanks.
3966 (1977): Measurement of fluid flow in closed conduits – Velocity area method using Pitot static tubes.
4373 (1979): Measurement of liquid flow in open channels – Water level measuring devices.
(1980): Measurement of fluid flow by means of orifice plates, nozzles and Venturi tubes inserted in
circular cross-section conduits running full.
5168 (1978): Measurement of fluid flow–Estimation of uncertainty of a flow-rate measurement.
7066: Assessment of uncertainty in the calibration and use of flow measurement devices.
7066-1 (1989): Part 1: Linear calibration relationships.
7066-2 (1988): Part 2: Non-linear calibration relationships.

—13
41©IEC
FIELD ACCEPTANCE TESTS TO DETERMINE
THE HYDRAULIC PERFORMANCE OF HYDRAULIC TURBINES,
STORAGE PUMPS AND PUMP-TURBINES
SECTION ONE – GENERAL RULES
Scope and object
1 Scope
1.1 This International Standard covers the arrangements for tests at the site to determine the extent to which
the main contract guarantees (see 3.2) have been satisfied. It contains the rules governing their conduct and
ase of the tests is disputed. It deals with methods of computation
prescribes measures to be taken if any ph
well the extent, content and style of the final repo rt.
of the results as as
1.2 Model tests, when used for acceptance purposes, are dealt with in IEC 193 with Amendment No. 1, first
supplement 193 A, and in IEC 497.
1.3 Tests of speed governing systems are dealt with in IEC 308.
Object
The purpose of this standard for field acceptance tests of hydraulic turbines, storage pumps or pump-
turbines, also called the machine, is:
– to define the terms and quantities which are used;
to specify methods of testing and ways of measuring the quantities involved in order to ascertain the
–
hydraulic performance of the machine;
to determine if the contract guarantees which fall within the scope of this standard have been fulfilled.
–
The decision to perform field acceptance tests including the definition of their scope is the subject of an
lier of the machine. For this, it has to be examined in each
agreement between the purchaser and the supp
case, whether the measuring conditions recommended in this standard can be realized. The influence on
the measuring uncertainties, due to hydraulic and civil conditions has to be taken into account.
If the actual conditions for field acceptance tests do not allow compliance with the guarantees to be
proved, it is recommended that acceptance tests be performed on models (see 1.1.2).
Types of machines
In general, this standard applies to any size and type of impulse or reaction turbine, storage pump
or pump-turbine. In particular, it applies to machines coupled to electric generators, motors or motor-
generators.
a turbine and the
as
For the purpose of this standard the term turbine includes a pump-turbine functioning
term pump includes a pump-turbine functioning as a pump. The term generator includes a motor-generator
functioning as a generator and the term motor includes a motor-generator functioning as a motor.

— 15 —
41 © IEC
1.4 Reference to IEC and ISO Standards
IEC and ISO Standards referred to in this standard are listed in the preface. If a contradiction is found
between this standard and another IEC or ISO standard, this standard shall prevail.
1.5 Excluded topics
1.5.1 This standard excludes all matters of a purely commercial interest except those inextricably bound up with
the conduct of the tests.
1.5.2 This standard is concerned neither with the structural details of the machines nor with the mechanical
properties of their components.
2. Terms, definitions, symbols and units
2.1 General
The common terms, definitions, symbols and units used throughout the standard arc listed in this clause.
Specialised terms arc explained where they appear.
The following terms arc given in 5.1.2 and Figure 11:
comprises the readings and/or recordings sufficient to calculate the performance of the machine
1) A run
at one operating condition.
is established by one or more consecutive runs at the same operating conditions and unchanged
2) A point
settings.
A test comprises a collection of data and results adequate to establish the performance of the machine
3)
over the specified range of operating conditions.
The clarification of any contested term, definition or unit of measure shall be agreed to in writing by the
contracting parties, in advance of the test.
2.2 Units
The International System of Units (SI) has been used throughout this standard*.
2). The basic
All terms are given in SI base units or derived coherent units (e.g. N instead of kg  m  s-
equations arc valid using these units. This has to be taken into account, if other than coherent SI Units are
5 Pa)
for certain data (e.g. kilowatt or megawatt instead of watt for power, kilopascal or bar (= 10
used.
instead of s- 1 for rotational speed, etc.). Temperatures may be given
instead of pascal for pressure, min -1
in degrees Celsius because thermodynamic (absolute) temperatures (in kelvins) are rarely required.
Any other system of units may be used but only if agreed to in writing by the contracting parties.
2.3 List of terms, definitions, symbols and units
2.3.1 Subscripts and symbols
The terms high pressure and low pressure define the two sides of the machine irrespective of the flow
direction and therefore are independent of the mode of operation of the machine.
* See ISO 31-3.
41 © IEC —
17 —
Sub-clause Term Definition Subscript
symbol
2.3.1.1 High pressure The high pressure section of the machine 1
reference to which the performance guarantees refer
section (see Figure 1)
2.3.1.2 Low pressure The low pressure section of the machine 2
reference
to which the performance
section guarantees refer (see Figure 1)
2.3.1.3 High pressure Whenever possible these sections 1', 1", .
measuring should coincide with section 1:
sections otherwise the measured values shall
be adjusted to section 1
(see 11.2.1)
2.3.1.4 Low pressure Whenever possible these sections 2', 2", .
measuring should coincide with section 2:
sections otherwise the measured values shall
be adjusted to section 2
(see 11.2.1)
2.3.1.5 Specified Subscript denoting values of sp
quantities such as speed, discharge
etc. for which other quantities are guaranteed
2.3.1.6 Maximum Subscripts denoting maximum max
Minimum or minimum values of any term min
2.3.1.7 Limits Contractually defined values:
— not to be exceeded
ffffK
O
—to be reached F
2.3.1.8 Ambient Subscript referring to surrounding atmospheric conditions amb
Turbine
Pump
IEC 362/91
Figure 1— Schematic representation of a hydraulic machine

— 19 —
41 © IEC
2.3.2 Geometric terms
Symbol Unit
Sub-clause Tenn Definition
2.3.2.1 Net cross sectional area normal to A m2
Area
general flow direction
2.3.2.2 Guide vane Average vane angle measured from a degree
opening closed position* or average
shortest distance between a m
adjacent guide vanes (at a defined
position, if necessary)
(see Figure 2)
2.3.2.3 Needle Average needle stroke measured s m
opening from closed position'
(impulse
turbine)
degree
2.3.2.4 Runner Average runner blade angle measured 0
blade from a given position*
opening
2.3.2.5 Elevation of a point in the system z to
Level
above the reference datum
(usually mean sea level)
2.3.2.6 Difference of elevation between m
Difference Z
any two points in the system
of levels
lEC 363/91
Figure 2 — Guide vane opening (from closed position)
* Under normal working oil pressure.

41 © IEC — 21 —
2.3.3 Physical quantities and properties
Sub-clause Tenn Definition Symbol Unit
s-2
2.3.3.1 as a function g m •
Acceleration Local value of g
duc
to of altitude and latitude of
gravity
the place of testing
(see Appendix E, Table EI)
K
2.3.3.2 Temperature Thermodynamic temperature; O
Celsius temperature r9 = O — 273,15 r9 °C
m-3
2.3.3.3 Density Mass per unit volume kg •
m-3
a) Values for water are given in kg •
B w
Appendix E, Table EII (g is commonly
used instead of w)
e
Values for air are given in 0, kg • m-3
b)
Appendix E, Table EIII. Usually
the value of air density at
the reference level of the
machine (see 2.3.7.10)
is used
kg • m-3
c) Values for mercury are given in p jig
Appendix E, Table EIV
2.3.3.4 Specific Volume per unit mass. Used only for 11g m3 • kg-1
volume water in this standard
m3 - kg-1
2.3.3.5 Isothermal Factor characterizing a thermodynamic
a
factor property. Values for water are given
in Appendix E, Table EV
J
2.3.3.6 Specific The rate of change of enthalpy per cR .kg- 1 • °C-1
heat unit mass with change in temperature or
J
capacity at constant pressure. Values for water • kg-1 • K-1
arc given in Appendix E, Table EVI
l'a
2.3.3.7 Vapour For purposes of this standard the p ,
v
pressure absolute partial pressure of the
(absolute) vapour in the gas mixture over the
liquid surface is the saturation
vapour pressure corresponding to the
temperature. Values for distilled
water arc given in Appendix E, Table EVII
A quantity characterising theµPa • s
2.3.3.8 Dynamic
mechanical behaviour of a fluid
viscosity
(sec ISO 31-3)
Ratio of the dynamic viscosity to the v m2 • s-1
2.3.3.9 Kinematic
viscosity density: v = L
e
41 © IEC — 23 —
2.3.4 Discharge, velocity and speed terms
Sub-clause Term Definition Symbol Unit
2.3.4.1 Discharge Volume of water per unit time flowing through any section Q m3 • s-1
(volume flow rate) in the system
2.3.4.2 Mass flow rate Mass of water flowing through any section of the system kg • s -1
(eQ)
per unit time. Both e and Q must be determined at the
same section and at the conditions existing in that section
Note. – The mass flow rate is constant between two
sections if no water is added or removed.
2.3.4.3 Measured
Volume of water per unit time flowing through any Q1, or Q 2, m3 • s-1
discharge
measuring section, for example 1' (see 2.3.1.3 and
2.3.1.4)
2.3.4.4 Discharge at Volume of water per unit time flowing through the or Q., m3 • s-1
Q1
reference section reference section 1 or 2
s-1
2.3.4.5 Corrected Volume of water per unit time flowing through a reference Q1 or Q2c m3 •
c
discharge at section referred to the ambient pressure
reference section (see 2.3.5.2) e.g.
Q1c — (eQ)llepamb
(sec 3.2.3) where gip. is the density at ambient
mb
pressure and the water temperature at the reference
section
2.3.4.6 No-load turbine Turbine discharge at no-load, at specified speed and Qo m3 • s-1
discharge specified specific hydraulic energy and generator not
excited
2.3.4.7 Index discharge Discharge given by relative (uncalibrated) flow m3 • s-1
Q;
measurement (see Clause 15) -
m . s-1
2.3.4.8 Mean velocity Discharge divided by the area v
A
2.3.4.9 Rotational speed Number of revolutions per unit time n 3-1
2.3.4.10 No load turbine The steady state turbine speed at no load with governor no s-1
speed connected and generator not excited
s-1
2.3.4.11 Initial speed The steady state turbine speed just before a ch ange in n 1
operating conditions is initiated (see Figure 3)
s-1
2.3.4.12 Final speed The steady state turbine speed after all transient waves n r
have been dissipated (see Figure 3)
specified load
2.3.4.13 Momentary The highest speed attained during a sudden n s-1
overspeed of a rejection from a specified governor setting
turbine (sec Figure 3)
s-1
Maximum The momentary overspeed attained under the most
2.3.4.14
m max
momentary unfavourable transient conditions (in some cases
overspeed of a the maximum momentary overspeed can exceed the
turbine maximum steady state runaway speed)
s-1
2.3.4.15 Maximum steady the speed for that position of needles or guide vanes
n R max
state runaway and/or runner/impeller blades which gives the highest
speed value after all transient waves have been dissipated with
electrical machine disconnected from load or network and
not excited, under the maximum specific hydraulic energy
(head). The runaway speed particularly of high specific
speed machines may be influenced by cavitation and thus
depends on the available LAPSE (see 2.3.6.9)

41©IEC —25 —
i
ni
nt
1EC 364/91
Figure 3 — Variation of turbine speed during a sudden load rejection
2.3.5 Pressure terms
Sub-Clause Tenn Definition Symbol Unit
Pa
2.3.5.1 Absolute The static pressure of a fluid measurement with
gabs
pressure reference to a perfect vacuum
2.3.5.2 Ambient pressure The absolute pressure of the ambient air Pa
Pamb
2.3.5.3 Gauge pressure The difference between the absolute presssure of a p Pa
fluid and the ambient pressure at the place and time
of measurement:
P — paba — Pamb
2.3.5.4 Initial pressure The steady state gauge pressure which occurs at a p; Pa
specified point of the system just before a change in
operating conditions is initiated (see Figure 4)
2.3.5.5 Final pressure The steady state gauge pressure which occurs at a p r Pa
specified point of the system after all transient waves
have been dissipated (see Figure 4)
Pa
2.3.5.6 Momentary The highest/lowest gauge pressure which occurs at a
pm
p; Pa
pressure specified point of the system under specified transient
conditions (see Figure 4)
Pa
2.3.5.7 Maximum/ The momentary pressure under the most unfavourable
P, max
– Pa
minimum transient condition
p
m min
momentary
pressure
41 © IEC —
27 —
a)
Pf
b)
Pi
IEC 36519!
Figure 4a — Variation of pressure at the turbine high pressure reference section
a) when a specified load is suddenly rejected
b) when a specified load is
suddenly accepted
Pf
IEC 366191
Figure 4b — Variation of pressure at the pump high p ssure
re
reference section during a power failure

41© IEC —29 —
2.3.6 Specific energy terms
In the International System of Units the mass (kg) is one of the base quantities. The energy per unit
mass, known as specific energy, is used in this standard as a primary term instead of the energy per local
unit weight which is called head and was exclusively used in the former IEC 41 and 198.
The latter term (head) has the disadvantage that the weight depends on the acceleration due to gravity
which changes mainly with latitude but also with altitude. Nevertheless, the term head will still remain
g,
in use because it is very common. Therefore both related energy terms are listed, the specific energy terms
g,
in this sub-clause and the head terms in 2.3.7. They differ only by the factor which is the local value of
acceleration due to gravity.
The symbol for specific energy at any section of flow is the small letter e; the symbol for the difference
h and
of specific energies between any two sections is the capital letter E. The same applies to H.
Term Definition Symbol Unit
Sub-clause
2.3.6.1 Specific energy The energy per unit mass of water at any section e J - kg-1
(m2 . s-2)
Specific energy of water available between the J • kg-1
2.3.6.2 Specific E
high and low pressure reference sections of the
hydraulic energy
machine, taking into account the influence of the
of machine
compressibility
= v2 v2
E Pabst — Pabst 1 2 +9
+ (z1 — z2)
Q 2
22 +.
with T. 1 2 and g . •
Note. — The value of gravity acceleration at the
reference level of the machine (see 2.3.7.10) may be
assumed as T.
and e2 can be calculated from
The values of
el
respectively, taking into account 491
and
pabsl pabs2
for both values, given the negligible influence
or 492
of the difference of the temperature on e
J • kg- 1
2.3.6.3 Specific Mechanical power transmitted through the coupling Em
d shaft (see Clause 14)
mechanical of the runner(s)/impeller(s) an
energy at divided by mass flow rate:
runner(s)/ p
Em = " (for Pm , see 2.3.8.4)
impeller(s
(eQ)1
J • kg- 1
Specific Specific hydraulic energy available between head Eg
2.3.6.4
ant
hydraulic energy water level and tailwater level of the pl
of the pl ant (see Figure 6)
It is given by:
pa h
,
E = 3 — Pahs4 v23 — v4
+ +(z3 —
z4)
B 2
e
e.2^4 93294
with -J. and
9_
The water density at ambient pressure may be
assumed as
e-
Figures 5a, 5b (reaction machines) and 5c (impulse turbines) illustrate some common cases of application of the basic formula for
the specific hydraulic energy. The applicable simplified formula is given under each figure. Measurement methods for the evaluation
of the specific hydraulic energy of the machine arc described in detail in Clause 11.
 See Appendix F.
31 —
41 © IEC —
Symbol Unit
Sub-clause Term Definition
Pump specific energy at specified speed and specified E0 J • kg-1
2.3.6.5 Zero-discharge
runner/impeller blade settings with high
(shut-off) guide vane and
specific hydraulic pressure side shut-off
energy of the
pump
J • kg-1
Specific The specific hydraulic energy dissipated between any two EL
2.3.6.6
hydraulic energy sections
loss
ELs J • kg-1
2.3.6.7 Suction specific The specific hydraulic energy dissipated between the
d the low pressure reference section of
hydraulic energy tailwater level an
loss the machine (see figure 41)
E J • kg-1
2.3.6.8 Suction specific Specific potential energy corresponding to the difference
potential energy between the reference level of the machine (see 2.3.7.10)
of the machine and the piezometric level at section 2:
Zs (see Figure 7)
,.
Es = 92 (z — = 2
z 2, )
NPSE J • kg-1
2.3.6.9 Net positive Absolute specific energy at section 2 minus the specific
referred to the
suction specific energy due to vapour pressu re per',
reference level of the machine according to Figure 7
energy
L2
Paba2 — Pva +
= NPSE
92(z r — z2) **
e2 2
2.3.7 Height and head terms
Unit
Symbol
Sub-clause Term Definition
d m
Geodetic height Difference in elevation between headwater level an Z g
2.3.7.1
of plant"* tailwater level of plant (see Figure 6)
h m
2.3.7.2 IIcad Energy per unit weight of water at any section
h = e/g
For definition of e, see 2.3.6.1
H m
Turbine or pump H = En
233.3
head
For definition of E, see 2.3.6.2
H
2.3.7.4 Plant head*** H g = Eg /g m
see 2.3.6.4
For definition of Eg ,
He m
Zero-discharge Ho = Eo
2.3.7.5 /79
(shut-off) head of
For definition of E0 , see 2.3.6.5
pump
HL
head loss HL = m
2.3.7.6 EL/9
For definition of EL , see 2.3.6.6
Appendix E, Table EVII.
 See 2.3.3.7 and
" For definition of cavitation factor a, sec IEC 193A and 497.
d plant head.
an
 Figure 6 shows the relationship between geodetic height of plant

33 —
41 © IEC —
Symbol Unit
Sub-clause Term Definition
m
IILs = TE 's "Ls
2.3.7.7 Suction head loss
see 2.3.6.7
For definition of ELs ,
Es
m
Suction height Zs = — (see Figure 7) Zs
2.3.7.8
For definition of Es , see 2.3.6.8
NPSE
in
NPSH
2.3.7.9 Net positive NPSH =
suction head 92
see 2.3.6.9
For definition of NPSE,
m
Elevation of the point of the machine taken as z r
2.3.7.10 Reference level
reference for the setting of the machine as defined in
of the machine
Figure 8
1EC 367/91
Figure 5a – Low-head machines – Determination of specific hydraulic energy of machine

41 © IEC
— 35 —
Water column manometers arc applied at point 1 and 2.
_ ^
/
vl
(Pabst ^ab^s- + (
v2
+
E_ JII _
z
J( l — z2)
The compressibility of water is neglected because the difference of pressure between 1 and 2 is small
therefore:
P1=P2= P
Hence:
l, — z
=
Pabs 1 P . J(z 1) + pambl,
z
=
Pabs 2 P - 9(z2, — 2) + pamb2,
— z,,)
Pamb 1 pamb 2 — ea . 3(z1,
, — , —
and therefore the simplified formula is:
^ (vj—
(v^—v;)—^ (1 Oa v')
E zl 2 r Z 1— ^ +
,—z , 1— + J Pa J( ) t
2 2
The water density at ambient pressure may be assumed as 13.

Vertical shaft unit
Horizontal shaft unit
EEC 368/91
Figure 5b — Medium and high-head machines — Determination of specific hydraulic energy of machine
and 2.
Pressure gauges manometers are applied at points 1
z
V:3)
= (Pabs l ^ i/abs2  E = .5H + (vl

-+ J(
z 1 — z2)
H,
Z is small compared to
The difference in ambient pressure between 1' and 2' is neglected because
therefore:
pamb2 i — Pamb
Pambl' =
Since both and Z2 are small compared to H, it may be assumed that:
Z 1
Pl 2
Z1  = Z and Z 2
=
Z2
e
41 © IEC — 37 —
hence:
pamb where p 1, is the gauge pressure measured at 1'
P1
T abs, = , + Z1  el ' 9 +
e2 .-Ù- where p 2, is the gauge pressure measured at 2'
2'9 +
pab, = P2' + Z2  pamb
and therefore the simplified formula is:
(Pl i — P2') (y? — v?) _ ^P1^ — P2^) lvï — v3)
E = – I ^ (z 1 2 Z + , – z ,) } 2 – 1 g
–
!EC 369/91
Figure 5c – Pelton turbines with vertical axis – Determination of specific hydraulic energy of machine
Case of non-pressurised housing.
It is conventionally assumed that the low pressure reference section corresponds to the plane at elevation
z, and that the pressure inside the housing is equal to the ambient pressure in the case of non-pressurised
housing.
(Albs ^ — Pabs^ ) vi) lvl — (
E
+ +9
l-1 -2)
-
II,
The difference in ambient pressure between 1' and 2 is neglected because Z is small compared to
therefore:
Pambl i = Pamb2 = Pamb
For the same reason it is assumed that:
P 1
Z  =Z
hence:
amb where pl, is the gauge pressure measured at 1'
P
Pabst = Pi, + Z  91 ' 9 +
Pabst = Pamb
41 © IEC — 39 —
As z 1 = z2 and assuming v 2 = 0, the simplified formula is:
E = =p'+^Z +vï
pl'-F^  (
z 1, '21+ ^
3 and 4 refer to the
water levels at the outer
boundaries of the plant
Z4
Reference datum
^ Z3—Z4
=
IEC 370/91
and head H of plant
Figure 6 - Hydroelectric plant - Determination of specific hydraulic energy E g g
through geodetic height of plant Zg
The general formula is:
(v3 —
pabs4 (pabs3 — )
vi)
=
E g 93-4' + 93-4(z3— z4)
Hg- +
2 e3-4
-
9s = -,
+Q4
^ Assuming
= 2
g Js-4
- z4);
a • •
Pabs3 — Pabs 4 - —e 9
assuming y3 = y4 = 0
water density at the ambient pressure, the formula becomes:
and n __ = =+ =
3 i
r n
[1— g • I1 —=1
=9•Z
Eg=J•(z
3 -z4)'
^ J E/
Aa L
is assumed equal to air density at the reference level of the machine.
where n a
Conversely:
+ turbine
where
Eg =E ^^
- pump
— 41 —
41 © IEC
Reference level of
the machine
(see 2.3.7.10)
IEC 371/91
NPSI-1
and net positive suction head,
NPSE,
Figure 7 — Net positive suction specific energy,
Water column manometer is applied at point 2.
v;
(Pabs — Pva)
NPSE = g2 NPSH = 2 + 2 r — z2^
g2  ( z
e2
With:
(2.2i — z2)
g + pamb2i
— e2 ' 2 
Pabs2
the simplified formula becomes:
Pva) v2
(pamb.,r —
(p Pva)va) + v;
amb2r —
, ) g2 S
_
g_ r — = +
z 2
'Z
°2
g2
is positive if the level 2' is lower than the reference level of the machine and vice versa.
where Zs
41 © IEC —
43 —
a) b) d)
Reference datum
6) f)
0 Reference datum
1FC
0° < a < 90°
a) Radial machines, such as Francis turbines, radial (centrifugal) pumps and pump-turbines; for multistage
machines: low pressuré stage.
b) Diagonal (mixed-flow, semi-axial) machines with fixed runner/impeller blades and with runner/impeller band.
c) Diagonal (mixed-flow, semi-axial) machines with fixed runner/impeller blades, without runner/impeller band.
d) Diagonal (mixed-flow, semi-axial) machines with adjustable runner/impeller blades).
e) Axial machines, such as propeller turbines, tubular turbines*', axial pumps and pump-turbines with fixed
runner/impeller blades.
,fl Axial machines, such as Kaplan turbines, tubular turbines**, axial pumps and pump-turbines with adjustable
runner/impeller blades.
g) Pelton turbines.
Figure 8 – Reference level of turbines, pumps and pump-turbines*
2.3.8 Power terms
Note.— All electrical power terms are defined in Clause 12.
Sub-clause Tent Definition Symbol Unit
2.3.8.1 lIydraulic power The hydraulic power available for producing power Ph W
(turbine) or imparted to the water (pump)
OPh
Ph = E(0Q)1 f
Hydraulic power Correction term to be evaluated after a relevant API, W
2.3.8.2
correction analysis according to contractual definitions and local
conditions*** (see 9.2.3)
* The reference level of the machine z r does not necessarily correspond to the point with maximum cavitation.
** The term "tubular turbines" includes bulb, pit, rim generator and S-type units.
q is taken from the system upstream of section 1 in a turbine and this water is contractually
*** Example: if a small discharge
chargeable to the hydraulic machine, the hydraulic power is: Ph =
E(2Q) 1 + E(eq)
41 © IEC — 45 —
Symbol Unit
Sub-clause Term Definition
The mechanical power delivered by the turbine shaft P W
2.3.8.3 Mechanical
power of the or to the pump shaft, assigning to the hydraulic
machine the mechanical losses of the relevant
machine (Power)
bearings (see Figure 9)
— For a turbine:
Pb+ Pc Pf
+ +Pd
P=Pa + Pe—
where:
Pa W
Pa is the generator power as measured at the
generator terminals
P b are the mechanical and electric losses in the Pb W
generator, including windage losses (see 12.1.2.1)
Q
are the thrust bearing losses due to generator. Pc W
Pc
In the case of a common thrust bearing, the bearing
losses shall be attributed to the turbine and generator
in proportion to the thrust of each on the bearing (see
12.1.2.2)
are the losses in all rotating elements external Pd W
Pd
to the turbine and to the generator, such as flywheel,
if any, gear, pump impeller in air, if any, etc. (see
12.1.2.3)
is the power supplied to any directly driven Pe W
Pe
auxiliary machine (see 12.1.2.4)
is the electric power supplied to the auxiliary Pf W
Pf
equipment of the turbine (e.g. for the governor) if the
contract specifies this to be chargeable to the turbine
— For a pump:
Pf
P=Pa—(Pb+Pc+Pd+Pe)+
where:
Pa is the power to the motor as measured at the Pa W
motor terminals
are the mechanical and electric losses in the Pb W
Pb
motor, including windage losses (see 12.1.2.1)
W
Pc are the thrust bearing losses due to the moto r. Pc
In the case of a common thrust bearing, the bearing
losses shall be attributed to the pump and motor in
ion to the thrust of each on the bearing (see
proport
12.1.2.2)
W
arc the losses in all rotating elements external Pd
Pd
d to the motor, such as flywheel, if any,
to the pump an
gear, starting turbine runner, turbine runner rotating
in air, etc. (see 12.1.2.3)
Pe is the power supplied to any directly driven Pe W
auxiliary machine (see 12.1.2.4)
P1 W
Pf is the electric power supplied to the auxiliary
equipment of the pump (e.g. for the governor) if the
contract specifies this to be chargeable to the pump

41 © IEC —
47 —
Sub-clause Term Definition Symbol Unit
2.3.8.4 Mechanical Mechanical power transmitted through the coupling Pm W
power of of the runner(s)/impeller(s) and the shaft (see
runner(s)/ demonstrative sketch Figure 9):
impeller(s)
— in the case of a turbine:
Pm=P+ Pf
PLm+
— in the case of a pump:
Pm =P — PLm — Pf
2.3.8.5 Mechanical Mechanical power dissipated
...

IEC 60404-3 ®
Edition 2.2 2010-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Magnetic materials –
Part 3: Methods of measurement of the magnetic properties of electrical steel
strip and sheet by means of a single sheet tester

Matériaux magnétiques –
Partie 3: Méthodes de mesure des caractéristiques magnétiques des bandes et
tôles magnétiques en acier à l'aide de l'essai sur tôle unique
IEC 60404-3:1992+A1:2002+A2:2009

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IEC 60404-3 ®
Edition 2.2 2010-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Magnetic materials –
Part 3: Methods of measurement of the magnetic properties of electrical steel
strip and sheet by means of a single sheet tester

Matériaux magnétiques –
Partie 3: Méthodes de mesure des caractéristiques magnétiques des bandes et
tôles magnétiques en acier à l'aide de l'essai sur tôle unique

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CJ
CODE PRIX
ICS 17.220.20; 29.030 ISBN 978-2-88910-186-3
– 2 – 60404-3 © IEC:1992+A1:2002+A2:2009
CONTENTS
FOREWORD.3
1 Object and field of application .5
2 Normative references .6
3 General principles .6
3.1 Principle of the method.6
3.2 Test apparatus .6
3.3 Air flux compensation .7
3.4 Test specimen.8
3.5 Power supply.8
4 Determination of the specific total loss .8
4.1 Principle of measurement .8
4.2 Apparatus.8
4.3 Measurement procedure of the specific total loss .9
5 Determination of magnetic field strength, excitation current and specific apparent
power .11
5.1 Principle of measurement .12
5.2 Apparatus.12
5.3 Measuring procedure.13
5.4 Determination of characteristics .14
5.5 Reproducibility .16

Annex A (normative) Requirements concerning the manufacture of yokes .19
Annex B (informative) Calibration of the test apparatus with respect to the Epstein
frame .20
Annex C (informative) Epstein to SST relationship for grain-oriented sheet steel .21
Annex D (informative) Digital sampling methods for the determination of the magnetic
properties .24

Bibliography.27

Figure 1 – Diagram of the test apparatus .17
Figure 2 – Yoke dimensions.17
Figure 3 – Diagram of the connections of the five coils of the primary winding .17
Figure 4 – Circuit for the determination of the specific total loss .18
Figure 5 – Circuit for measuring the r.m.s. value of the excitation current .18
Figure 6 – Circuit for measuring the peak value of the magnetic field strength .18
Figure C.1 – Epstein-SST conversion factor δP for grain-oriented material versus
magnetic polarization J .23
Figure C.2 – Epstein-SST conversion factor δHS for grain-oriented material versus
magnetic polarization J .23

Table C.1 – Epstein-SST conversion factors δP and δHS for grain-oriented material in
the polarization range 1,0 T to 1,8 T .22

60404-3 © IEC:1992+A1:2002+A2:2009 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MAGNETIC MATERIALS –
Part 3: Methods of measurement of the magnetic properties
of electrical steel strip and sheet by means
of a single sheet tester
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60404-3 has been prepared by IEC technical committee 68:
Magnetic alloys and steels.
This consolidated version of IEC 60404-3 consists of the second edition (1992) [documents
68(CO)68+75 and 68(CO)77+79], its amendment 1 (2002) [documents 68/258/FDIS and
68/263/RVD], its amendment 2 (2009) [documents 68/389/CDV and 68/397/RVC] and its
corrigendum of December 2009.
The technical content is therefore identical to the base edition and its amendments and has
been prepared for user convenience.
It bears the edition number 2.2.
A vertical line in the margin shows where the base publication has been modified by
amendments 1 and 2.
– 4 – 60404-3 © IEC:1992+A1:2002+A2:2009
Annex A forms an integral part of this standard.
Annex B, C and D are for information only.
The committee has decided that the contents of the base publication and its amendments 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.
IMPORTANT – The “colour inside” logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this publication using a colour printer.

60404-3 © IEC:1992+A1:2002+A2:2009 – 5 –
MAGNETIC MATERIALS –
Part 3: Methods of measurement of the magnetic properties
of electrical steel strip and sheet by means
of a single sheet tester
1 Object and field of application
The object of this part is to define the general principles and the technical details of the
measurement of the magnetic properties of magnetic sheets by means of a single sheet
tester.
This part of IEC 60404 is applicable at power frequencies to:
a) grain oriented magnetic sheet and strip:
for the measurement between 1,0 T and 1,8 T of:
– specific total loss;
– specific apparent power;
– r.m.s. value of the magnetic field strength;
for the measurement up to peak values of magnetic field strength of 1 000 A/m of:
– peak value of the magnetic polarization;
– peak value of the magnetic field strength.
b) non-oriented magnetic sheet and strip:
for the measurement between 0,8 T and 1,5 T of:
– specific total loss;
– specific apparent power;
– r.m.s. value of excitation current;
for the measurement up to peak values of magnetic field strength of 10 000 A/m of:
– peak value of the magnetic polarization;
– peak value of the magnetic field strength.
The single sheet tester is applicable to test specimens obtained from magnetic sheets and
strips of any quality. The magnetic characteristics are determined for a sinusoidal induced
voltage, for specified peak values of magnetic polarization and for a specified frequency.
The measurements are made at an ambient temperature of 23 °C ± 5 °C on test specimens
which have first been demagnetized.
NOTE Throughout this part the quantity "magnetic polarization" is used as defined in IEC 60050(901). In some
standards of the IEC 60404 series, the quantity "magnetic flux density" was used.

– 6 – 60404-3 © IEC:1992+A1:2002+A2:2009
2 Normative references
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 – Part 221: Magnetic materials
and components
IEC 60404-2, Magnetic materials – Part 2: Methods of measurement of the magnetic
properties of electrical steel strip and sheet by means of an Epstein frame
3 General principles
3.1 Principle of the method
The test specimen comprises a sample of magnetic sheet and is placed inside two windings:
– an exterior primary winding (magnetizing winding);
– an interior secondary winding (voltage winding).
The flux closure is made by a magnetic circuit consisting of two identical yokes, the cross-
section of which is very large compared with that of the test specimen (see figure 1).
To minimize the effects of pressure on the test specimen, the upper yoke shall be provided
with a means of suspension which allows part of its weight to be counterbalanced in
accordance with 3.2.1.
Care shall be taken to ensure that temperature changes are kept below a level likely to
produce stress in the test specimen due to thermal expansion or contraction.
3.2 Test apparatus
3.2.1 Yokes
Each yoke is in the form of a U made up of insulated sheets of grain oriented silicon steel or
nickel iron alloy. It shall have a low reluctance and a specific total loss not greater than
1,0 W/kg at 1,5 T and 50 Hz. It shall be manufactured in accordance with the requirements of
annex A.
In order to reduce the effect of eddy currents and give a more homogeneous distribution of
the flux over the inside of the yokes, the latter shall be made of a pair of C-cores or a glued
stack of laminations in which case the corners shall have staggered butt joints (see figure 1).
The yoke shall have pole faces having a width of 25 mm ± 1 mm.
The two pole faces of each yoke shall be coplanar to within 0,5 mm and the gap between the
opposite pole faces of the yokes shall not exceed 0,005 mm at any point. Also, the yokes
shall be rigid in order to avoid creating mechanical stresses in the test specimen.

60404-3 © IEC:1992+A1:2002+A2:2009 – 7 –
The height of each yoke shall be between 90 mm and 150 mm. Each yoke shall have a width
+5
of 500 mm and an inside length of 450 mm ± 1 mm (see figure 2).
−5
NOTE It is recognized that other yoke dimensions can be used provided that the comparability of the results can
be demonstrated.
There shall be a non-conducting, non-magnetic support between the vertical limbs of the
yokes on which the test specimen is placed. This support shall be centered and located in the
same plane as the pole faces so that the test specimen is in direct contact with the pole faces
without any gap.
The upper yoke shall be movable upwards to permit insertion of the test specimen.
After insertion the upper yoke shall be realigned accurately with the bottom yoke. The sus-
pension of the upper yoke shall allow part of its weight to be counterbalanced so as to give a
force on the test specimen of between 100 N and 200 N.
NOTE The square shape of the yoke has been chosen in order to have only one test specimen for non-oriented
material. By rotating the test specimen through 90° it is possible to determine the characteristics in the rolling
direction and perpendicular to the rolling direction.
3.2.2 Windings
The primary and secondary windings shall be at least 440 mm in length and shall be wound
on a non-conducting, non-magnetic, rectangular former. The dimensions of the former shall
be as follows:
– length: 445 mm ± 2 mm;
– internal width: 510 mm ± 1 mm;
– internal height: 5 mm;
−2
– height: ≤15 mm.
The primary winding can be made up of:
– either five or more coils having identical dimensions and the same number of turns
connected in parallel and taking up the whole length (see figure 3). For example, with five
coils, each coil can be made up of 400 turns of copper wire 1 mm in diameter, wound in
five layers;
– or a single continuous and uniform winding taking up the whole length. For example this
winding can be made up of 400 turns of copper wire 1 mm in diameter, wound in one or
more layers.
The number of turns on the secondary winding will depend on the characteristics of the
measuring instruments.
3.3 Air flux compensation
Compensation shall be made for the effect of air flux. This can be achieved, for example, by a
mutual inductor. The primary winding of the mutual inductor is connected in series with the
primary winding of the test apparatus, while the secondary winding of the mutual inductor is
connected to the secondary winding of the test apparatus in series opposition.
The adjustment of the value of the mutual inductance shall be made so that, when passing an
alternating current through the primary windings in the absence of the specimen in the
apparatus, the voltage measured between the non-common terminals of the secondary
windings shall be no more than 0,1 % of the voltage appearing across the secondary winding
of the test apparatus alone.
– 8 – 60404-3 © IEC:1992+A1:2002+A2:2009
Thus the average value of the rectified voltage induced in the combined secondary windings
is proportional to the peak value of the magnetic polarization in the test specimen.
3.4 Test specimen
The length of the test specimen shall be not less than 500 mm. Although the part of
the specimen situated outside the pole faces has no great influence on the measurement,
this part shall not be longer than is necessary to facilitate insertion and removal of the test
specimen.
The width of the test specimen shall be as large as possible and at its maximum equal to
the width of the yokes.
For maximum accuracy, the minimum width shall be not less than 60 % of the width of
the yokes.
The test specimen shall be cut without the formation of excessive burrs or mechanical
distortion. The test specimen shall be plane. When a test specimen is cut, the edge of
the parent strip is taken as the reference direction. The following tolerances are allowed
for the angle between the direction of rolling and that of cutting:
±1° for grain oriented steel sheet;
±5° for non-oriented steel sheet.
For non-oriented steel sheet, two specimens shall be cut, one parallel to the direction
of rolling and the other perpendicular unless the test specimen is square, in which case one
test specimen only is necessary.
3.5 Power supply
The power supply shall be of low internal impedance and shall be highly stable in terms
of voltage and frequency. During the measurement, the voltage and the frequency shall be
maintained constant within ±0,2 %.
In addition, the waveform of the secondary induced voltage shall be maintained as sinusoidal
as possible. It is preferable to maintain the form factor of the secondary voltage to within ±1 %
of 1,111. This can be achieved by various means, for example by using an electronic
feedback amplifier.
4 Determination of the specific total loss
4.1 Principle of measurement
The single sheet tester with the test specimen represents an unloaded transformer the total
loss of which is measured by the circuit shown in figure 4.
4.2 Apparatus
4.2.1 Voltage measurement
NOTE For the application of digital sampling methods, see Annex D.
4.2.1.1 Average type voltmeter
The secondary rectified voltage of the test apparatus shall be measured by an average type
voltmeter. The preferred instrument is a digital voltmeter having an accuracy of ±0,2 %.
NOTE Instruments of this type are usually graduated in average rectified value multiplied by 1,111.

60404-3 © IEC:1992+A1:2002+A2:2009 – 9 –
The load on the secondary circuit shall be as small as possible. Consequently, the internal
resistance of the average type voltmeter should be at least 1 000 Ω/V.
4.2.1.2 R.M.S. voltmeter
A voltmeter responsive to r.m.s. values shall be used. The preferred instrument is a digital
voltmeter having an accuracy of ±0,2 %.
4.2.2 Frequency measurement
A frequency meter having an accuracy of ±0,1 % shall be used.
NOTE For the application of digital sampling methods, see Annex D.
4.2.3 Power measurement
The power shall be measured by a wattmeter having an accuracy of ±0,5 % or better at the
actual power factor and crest factor.
NOTE For the application of digital sampling methods, see Annex D.
The resistance of the voltage circuit of the wattmeter shall be at least 100 Ω/V for all ranges.
If necessary, the losses in the secondary circuit shall be subtracted from the indicated loss
value.
The ohmic resistance of the wattmeter voltage circuit shall be at least 5 000 times its
reactance, unless the wattmeter is compensated for its reactance.
If a current-measuring device is included in the circuit, it shall be short-circuited when the
secondary voltage is adjusted and the losses are measured.
4.3 Measurement procedure of the specific total loss
NOTE For the application of digital sampling methods, see Annex D.
4.3.1 Preparation of measurement
The length of the test specimen shall be measured with an accuracy of ±0,1 % and its mass
determined within ±0,1 %. The test specimen shall be loaded and centred on the longitudinal
and transverse axes of the test coil, and the partly counterbalanced upper yoke shall be
lowered.
Before the measurement, the test specimen shall be demagnetized by slowly decreasing an
alternating magnetic field starting from well above the value to be measured.

– 10 – 60404-3 © IEC:1992+A1:2002+A2:2009
4.3.2 Source setting
The source shall be adjusted so that the average value of the secondary rectified voltage is:
R
i
U = 4 f N  AĴ (1)
2 2
R + R
i
t
where
U is the average value of the secondary rectified voltage, in volts;
f is the frequency, in hertz;
R is the combined resistance of instruments in the secondary circuit, in ohms;
i
R is the series resistance of the secondary windings of the test apparatus and mutual
t
inductor, in ohms;
N is the number of turns of the secondary winding;
A is the cross-sectional area of the test specimen, in square metres;
Ĵ is the peak value of magnetic polarization, in tesia.
The cross-sectional area A is given by the equation:
m
A = (2)
l ρ
m
where
m is the mass of the test specimen, in kilograms;
l is the length of the test specimen, in metres;
ρ is the density of the test material, in kilograms per cubic metre.
m
4.3.3 Measurements
4.3.3.1 The ammeter, if any, in the primary circuit shall be observed to ensure that the
current circuit of the wattmeter is not overloaded. The ammeter shall then be short-circuited
and the secondary voltage readjusted.

60404-3 © IEC:1992+A1:2002+A2:2009 – 11 –
After checking the waveform of the secondary voltage, the wattmeter shall be read. The value
of the specific total power loss shall then be calculated from the equation:
⎡ ⎤
(1,111 U )
N l
⎢ ⎥
P = P −  (3)
s
N R m l
⎢ ⎥
2 i m
⎣ ⎦
where
U is the average value of the secondary rectified voltage, in volts;
P is the specific total power loss of the test specimen, in watts per kilogram;
s
P is the power measured by the wattmeter, in watts;
m is the mass of the test specimen, in kilograms;
l is the conventional magnetic path length, in metres (l = 0,45 m);
m m
l is the length of the test specimen, in metres;
N is the number of turns of the primary winding;
N is the number of turns of the secondary winding;
R is the combined resistance of instruments in the secondary circuit, in ohms.
i
*
NOTE 1 Studies have shown that the inside length of the yokes is an appropriate mean value for the effective
magnetic path length l for different materials and polarization values.
m
NOTE 2 A long established practice in a few countries is to calibrate the test apparatus by determination of the
effective magnetic path length based on specific total power loss measurements made in an Epstein frame.
The details of the calibration procedure are described in annex B. This practice is permitted only for the evaluation
of magnetic sheet and strip intended for consumption in those countries.
4.3.3.2 In the case of non-oriented material, for values of the specific total loss specifid
in the product standards for magnetic materials, the reported value of the specific total loss
shall be calculated as the average of the two measurements made for the directions parallel
and perpendicular to the direction of rolling. For other purposes the values of the specific total
loss parallel and perpendicular to the direction of rolling shall be reported separately.
4.3.4 Reproducibility
The reproducibility of this method using the test apparatus defined above is characterized by
a relative standard deviation of 1 % for grain oriented steel sheet and 2 % for non-oriented
steel sheet.
5 Determination of magnetic field strength, excitation current
and specific apparent power
This clause describes measuring methods for the determination of the following
characteristics:
– r.m.s. value of the excitation current Ĩ ;
ˆ
– peak value of magnetic field strength H
– specific apparent power S .
s
________
*
J. D. Sievert, Determination of AC Magnetic Power Loss of Electrical Steel Sheet: Present Status and
Trends, IEEE Trans. Mag. Vol. 20, No. 5 (1984) 1702-1707.

– 12 – 60404-3 © IEC:1992+A1:2002+A2:2009
5.1 Principle of measurement
5.1.1 Peak value of magnetic polarization
The peak value of magnetic polarization shall be derived from the average value of the
rectified secondary voltage measured as described in 4.2.1.
5.1.2 R.M.S. value of the excitation current
The r.m.s. value of the excitation current shall be measured by an r.m.s. ammeter in the
circuit shown in figure 5.
5.1.3 Peak value of the magnetic field strength
The peak value of the magnetic field strength shall be obtained from the peak value Î of the
primary current. This shall be determined by measuring the voltage drop across a known
precision resistor R using a peak voltmeter as shown in figure 6.
n
5.2 Apparatus
5.2.1 Average type voltmeter
The secondary rectified voltage of the test apparatus shall be measured by an average type
voltmeter. The preferred instrument is a digital voltmeter having an accuracy of ±0,2 %.
NOTE Instruments of this type are usually graduated in average rectified value multiplied by 1,111.
The load on the secondary circuit shall be as small as possible. Consequently, the internal
resistance of the average type voltmeter should be at least 1 000 Ω/V.
5.2.2 Current measurement
The r.m.s. value of the primary current shall be measured either by means of an r.m.s.
ammeter of low impedance of class 0,5 or better (see figure 5), or by using a precision
resistor and r.m.s. electronic voltmeter (see figure 6).
5.2.3 Peak current measurement
The measurement of the peak voltage across resistor R (see figure 6) shall be achieved
n
either by means of an electronic voltmeter of high sensitivity indicating the peak value, or by
means of a calibrated oscilloscope.
The full scale error of the device used shall be ±3 % or better.
5.2.4 Power supply
The power supply shall be in accordance with 3.5.

60404-3 © IEC:1992+A1:2002+A2:2009 – 13 –
5.2.5 Resistor R
n
The method shown in figure 6 requires a precision non-inductive resistor of a value known to
within ±0,5 %.
The resistance value to be chosen depends upon the sensitivity of the peak voltmeter. It shall
not exceed 1 Ω in order to minimize the distortion of the induced voltage waveform.
5.3 Measuring procedure
5.3.1 Preparation for measurement
The length of the test specimen shall be measured with an accuracy of ±0,1 % and its mass
determined within ±0,1 %. The test specimen shall be loaded and centered on the longitudinal
and transverse axes of the test coil, and the partly counterbalanced upper yoke shall be
lowered.
Before the measurement, the test specimen shall be demagnetized by slowly decreasing an
alternating magnetic field starting from well above the value to be measured.
5.3.2 Measurement
In practice, single values or groups of values of magnetic polarization Ĵ and magnetic field
~
ˆ
strength ( H or H ) are determined.
If the magnetic field strength is specified and the magnetic polarization is to be determined,
the primary current shall be set to give the relevant magnetic field strength (see below).
Then the secondary voltage of the single sheet tester shall be read on the average type
voltmeter (see 4.3.2).
Again, if the magnetic polarization is specified and the magnetic field strength is to be
determined, the secondary voltage shall be set to its specified value as described in 4.3.2.
~
For the determination of H , the r.m.s. value of the primary current shall be read on the
ammeter according to the circuit of figure 5 or on the voltmeter according to the circuit of
figure 6.
ˆ
For the determination of H , the peak value of the voltage drop across resistor R shall be
n
read on the peak voltmeter.
5.3.3 Non-oriented material
In the case of non-oriented material, for the peak value of the magnetic polarization Ĵ
specified in the product standards for magnetic materials, the reported value of Ĵ shall be
calculated as the average of the two measurements made for the directions parallel and
perpendicular to the direction of rolling. For values of Ĵ for other purposes and for the
measurement of specific apparent power and the r.m.s. value of excitation current, the values
parallel and perpendicular to the direction of rolling shall be reported separately.

– 14 – 60404-3 © IEC:1992+A1:2002+A2:2009
5.4 Determination of characteristics
5.4.1 Determination of Ĵ
The peak value of the magnetic polarization is given by the equation:
Ĵ =  U  (4)
4 f N A
To obtain U , the voltmeter reading shall be corrected by the factor:
R + R
v 2
R
v
where
Ĵ is the peak value of the magnetic polarization, in tesia;
f is the frequency, in hertz;
N is the number of turns of the secondary winding;
A is the cross-section of the test specimen, in square metres;
R is the voltmeter internal resistance, in ohms;
v
R is the resistance of the secondary winding, in ohms;
U is the average value of the secondary rectified voltage, in volts.
~
5.4.2 Determination of H
The r.m.s. value of the magnetic field strength shall be calculated from the r.m.s. value of
primary current indicated by the ammeter according to the circuit of figure 5 or by the volt-
meter according to the circuit of figure 6:
N
~
H =  Ĩ; (5)
l
m
where
~
H is the r.m.s. value of the magnetic field strength, in amperes per metre;
N is the number of turns of the primary winding;
l is the conventional effective magnetic path length, in metres (l = 0,45 m);
m m
Ĩ is the r.m.s. value of primary current, in amperes.
~
After several groups of corresponding values of Ĵ and H have been determined, the magne-
~
tization curve of Ĵ against H can be drawn.

60404-3 © IEC:1992+A1:2002+A2:2009 – 15 –
ˆ
5.4.3 Determination of H
ˆ
The peak value of the magnetic field strength shall be calculated from the reading U of the
m
peak voltmeter:
N
ˆ ˆ
H =  U (6)
m
R l
n m
where
ˆ
H is the peak value of the magnetic field strength, in amperes per metre;
R is the resistance value of the precision resistor in figure 6, in ohms;
n
ˆ
U is the peak voltage drop across R , in volts.
n
m
NOTE The amplitude permeability is expressed as:
ˆ
J
µ = + 1
a
ˆ
μ H
o
5.4.4 Determination of S
s
The apparent power is given by:
N N
1 1
S = Ĩ · Ũ = Ĩ · 1,111 · U ⋅  (7)
1 2 1
N N
2 2
where
S is the apparent power, in voltamperes;
Ũ is the r.m.s. value of secondary voltage of the single sheet tester, in volts.
NOTE The relation Ũ = 1,111 U is valid only for sinusoidal voltage.
2 2
l
m
Division of this quantity by the effective mass m = m gives the specific apparent power:
a
l
~
I ⋅ 1,111 ⋅  U l N
1 2 1
S
S =  =  (8)
s
m ml N
a m 2
where
S is the specific apparent power, in voltamperes per kilogram;
s
l is the length of the test specimen, in metres;
m is the mass of the test specimen, in kilograms;
U is the average value of the secondary rectified voltage, in volts;
N is the number of turns of the primary winding;
N is the number of turns of the secondary winding;
l is the conventional effective magnetic path length, in metres (l = 0,45 m);
m m
Ĩ is the r.m.s. value of primary current, in amperes.
– 16 – 60404-3 © IEC:1992+A1:2002+A2:2009
5.5 Reproducibility
The reproducibility of this method using the test apparatus defined above is characterized
by a relative standard deviation of 3 % or less.

60404-3 © IEC:1992+A1:2002+A2:2009 – 17 –
IEC  2701/02
Figure 1 – Diagram of the test apparatus

IEC  2702/02
Figure 2 – Yoke dimensions
IEC  2703/02
Figure 3 – Diagram of the connections of the five coils of the primary winding

– 18 – 60404-3 © IEC:1992+A1:2002+A2:2009

IEC  2704/02
V measures average rectified voltage
V measures r.m.s. voltage
M is the mutual inductor
T is the test frame
Figure 4 – Circuit for the determination of the specific total loss

IEC  2705/02
Figure 5 – Circuit for measuring the r.m.s. value
of the excitation current
IEC  2706/02
Figure 6 – Circuit for measuring the peak value
of the magnetic field strength

60404-3 © IEC:1992+A1:2002+A2:2009 – 19 –
Annex A
(normative)
Requirements concerning the manufacture of yokes

It is important to ensure that the loss in the yokes is low and constant. A loss of 1 mW/kg at a
magnetic flux density of 40 mT is typical, measured at a frequency of 50 Hz. One of the ways
in which losses can become high is due to short circuits between laminations in the yoke.
For the measurement of the power loss in the yokes a primary and a secondary winding
wound on the yokes may be used; 25 turns are sufficient for each of these windings.
It is necessary to test the interlaminar resistance between parts of the yoke by use of an
ohmmeter and probes.
During the manufacture of the yokes, a stress relief annealing of the cut strips is required.
After bonding the material to build the yokes (which shall be done without application of high
pressure), the pole faces shall be machined. Parallelism shall be proven with an appropriate
gauge, and the uniformity of the air gap checked using engineers blue. Further grinding in
stages using carborundum and diamond paste will probably be necessary until a uniform
distribution of the engineers blue indicates a sufficiently homogeneous air gap. The grinding
can be carried out by putting the upper yoke in the normal position of use on top of the bottom
yoke and moving it to and fro through a small distance.
The process of grinding causes the metal to flow between laminations and produces short
circuits. It is important to remove this flowed metal by a careful acid etching process using a
non-oxidizing acid (e.g. hydrochloric acid). This consists in rubbing the pole faces with an
acid-soaked cloth until the flowed layer is removed. It is important to carefully wash and
neutralize the steel.
It is helpful to measure the yoke losses before and after grinding and etching to verify that the
loss has been reduced by this treatment.
A final check on interlaminar insulation shall be made after pole face etching and cleaning.
Before use, the yokes shall be carefully demagnetized from a magnetic flux density well
above the highest magnetic flux density which would occur in the yokes during use

– 20 – 60404-3 © IEC:1992+A1:2002+A2:2009
Annex B
(informative)
Calibration of the test apparatus with respect to the Epstein frame

NOTE This annex does not form part of the requirements of the standard. It is included for information for those
who wish to obtain the correlation between measurements taken by this method and the Epstein frame method
(see note 2, page 19).
The calibration of the test apparatus consists in the determination of the effective length of its
magnetic circuit from the measurement of the specific total loss in the Epstein frame.
This determination of the effective length of the magnetic circuit is made for each grade of
material and each magnetic flux density for which the specific total power losses are to be
determined.
Firstly the specific total power losses are measured by means of an Epstein frame in
accordance with IEC 60404-2 (except that, in the case of non-oriented material, all the strips
loaded in the Epstein frame shall be of the same orientation).
Then, at least 12 strips which have already been measured in the Epstein frame shall
be placed side by side in the test apparatus. The losses are measured again by the apparatus
for a magnetic flux density identical to that used in the determination of the specific total
power loss in the Epstein frame.
The effective length l of the magnetic circuit is then calculated in accordance with the
m
equation:
P l
l = (B.1)
m
mP
sE
where
P is the power measured by the wattmeter connected with the test apparatus, in watts;
l is the length of the Epstein strips, in metres;
m is the total mass of Epstein strips placed in the test apparatus, in kilograms;
P is the specific total power loss determined by the Epstein frame, in watts per kilogram.
sE
NOTE In the case of non-oriented materials, there will be two effective path lengths: one for each direction of
sampling.
60404-3 © IEC:1992+A1:2002+A2:2009 – 21 –
Annex C
(informative)
Epstein to SST relationship for grain-oriented sheet steel

NOTE This annex does not form part of the requirements of the standard. It is included for information for those
who wish to convert SST values into Epstein values and vice versa. There are two significant differences from the
procedure in annex B as follows:
– annex B prescribes the procedure of the calibration of an SST by means of long Epstein strips. It yields an
exact value for the Epstein/SST calibration factor for the individual sample under consideration;
– by cutting the sheets into strips, the procedure of annex B yields an Epstein/SST calibration factor which refers
to a stress-free sheet sample which is formed from the annealed Epstein strips. When using this calibration
procedure, specific total loss values determined for sheet specimens will agree more closely with those
determined using corresponding Epstein specimens if the sheet specimen
...