Transformers and inductors for use in electronic and telecommunication equipment - Measuring methods and test procedures

IEC 61007:2020 describes a number of tests for use in determining the significant parameters and performance characteristics of transformers and inductors for use in electronics and telecommunication equipment. These test methods are designed primarily for transformers and inductors used in all types of electronics applications that can be involved in any specification for such components. Even though these tests can be useful to the other types of transformers used in power distribution applications in utilities, industry, and others, the tests discussed in this document can supplement or complement the tests but are not intended to replace the tests in standards for transformers. Some of the tests described are intended for qualifying a product for a specific application, while others are test practices used for manufacturing and customer acceptance testing. The test methods described here include those parameters most commonly used in the electronics transformer and inductor industry: electric strength, resistance, power loss, inductance, impedance, balance, transformation ratio and many others used less frequently.
This edition includes the following significant technical changes with respect to the previous edition:
a) scope: the application of the scope of IEC 61007 was extended;
b) Clause 2: added new references and updated the references;
c) Clause 3: new definitions were added in 3.3, and in 3.7 the voltage-time product was redefined;
d) test procedures were updated;
e) environmental test procedures: new references were added;
f) Annexes A to G were added.

Transformateurs et inductances utilisés dans les équipements électroniques et de télécommunications - Méthodes de mesure et procédures d'essais

L'IEC 61007:2020 décrit plusieurs essais utilisés pour la détermination des paramètres importants et des caractéristiques de fonctionnement des transformateurs et inductances utilisés dans les équipements électroniques et de télécommunications. Ces méthodes d'essai sont principalement conçues pour les transformateurs et inductances utilisés dans tous les types d'applications électroniques qui peuvent être employés dans toute spécification de ces composants. Bien que ces essais puissent être utiles pour d'autres types de transformateurs utilisés dans les applications de distribution de puissance dans les services publics, dans l'industrie et d'autres secteurs, les essais traités dans le présent document peuvent s'ajouter aux essais décrits dans les normes relatives aux transformateurs ou les compléter, mais ne sont pas destinés à les remplacer. Certains des essais décrits visent à qualifier un produit pour une application spécifique, tandis que d'autres sont des pratiques d'essai utilisées lors de la fabrication et pour les essais d'acceptation client. Les méthodes d'essai décrites ici comprennent les paramètres les plus couramment utilisés dans l'industrie des transformateurs et inductances électroniques: rigidité diélectrique, résistance, perte de puissance, inductance, impédance, équilibre, rapport de transformation, et de nombreux autres paramètres utilisés moins fréquemment.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) domaine d'application: extension du domaine d'application de l'IEC 61007;
b) Article 2: ajout de nouvelles références et mise à jour des références;
c) Article 3: ajout de nouvelles définitions en 3.3, et redéfinition du produit tension-temps en 3.7;
d) mise à jour des procédures d'essai;
e) procédures d'essais d'environnement: ajout de nouvelles références;
f) ajout des Annexes A à G.

General Information

Status
Published
Publication Date
19-Jul-2020
Current Stage
PPUB - Publication issued
Completion Date
20-Jul-2020
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IEC 61007
Edition 3.0 2020-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Transformers and inductors for use in electronic and telecommunication
equipment – Measuring methods and test procedures
Transformateurs et inductances utilisés dans les équipements électroniques et
de télécommunications – Méthodes de mesure et procédures d'essais
IEC 61007:2020-07(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 61007
Edition 3.0 2020-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Transformers and inductors for use in electronic and telecommunication
equipment – Measuring methods and test procedures
Transformateurs et inductances utilisés dans les équipements électroniques et
de télécommunications – Méthodes de mesure et procédures d'essais
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.100.10; 29.180 ISBN 978-2-8322-8620-3

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 61007:2020 © IEC 2020
CONTENTS

FOREWORD ........................................................................................................................... 6

1 Scope .............................................................................................................................. 8

2 Normative references ...................................................................................................... 8

3 Terms and definitions ...................................................................................................... 9

4 Test procedures ............................................................................................................ 13

4.1 Test and measurement conditions ......................................................................... 13

4.1.1 General ......................................................................................................... 13

4.1.2 Measurement uncertainty............................................................................... 16

4.1.3 Alternative test methods ................................................................................ 16

4.2 Visual inspection ................................................................................................... 16

4.2.1 General ......................................................................................................... 16

4.2.2 Safety screen position ................................................................................... 16

4.2.3 Quality of joints ............................................................................................ 16

4.3 Dimensioning and gauging procedure ................................................................. 19

4.4 Electrical test procedures .................................................................................... 19

4.4.1 Winding resistance ...................................................................................... 19

4.4.2 Insulation tests .............................................................................................. 20

4.4.3 Losses ........................................................................................................... 23

4.4.4 Inductance ..................................................................................................... 27

4.4.5 Unbalance .................................................................................................... 27

4.4.6 Capacitance ................................................................................................. 32

4.4.7 Transformation ratios..................................................................................... 35

4.4.8 Resonant frequency ...................................................................................... 41

4.4.9 Signal transfer characteristics ....................................................................... 42

4.4.10 Cross-talk ...................................................................................................... 46

4.4.11 Frequency response ...................................................................................... 47

4.4.12 Pulse characteristics ...................................................................................... 48

4.4.13 Voltage-time product rating .......................................................................... 49

4.4.14 Total harmonic distortion .............................................................................. 50

4.4.15 Voltage regulation ......................................................................................... 51

4.4.16 Temperature rise ........................................................................................... 52

4.4.17 Surface temperature ..................................................................................... 53

4.4.18 Polarity .......................................................................................................... 54

4.4.19 Screens ........................................................................................................ 56

4.4.20 Noise ............................................................................................................ 57

4.4.21 Corona tests ................................................................................................. 58

4.4.22 Magnetic fields .............................................................................................. 58

4.4.23 Inrush current ................................................................................................ 61

4.5 Environmental test procedures ........................................................................... 61

4.5.1 General ......................................................................................................... 61

4.5.2 Soldering ...................................................................................................... 61

4.5.3 Robustness of terminations and integral mounting devices ............................ 61

4.5.4 Shock ............................................................................................................ 61

4.5.5 Bump ............................................................................................................. 62

4.5.6 Vibration (sinusoidal) ..................................................................................... 62

4.5.7 Acceleration, steady state .............................................................................. 62

4.5.8 Rapid change of temperature (thermal shock in air) ....................................... 62

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IEC 61007:2020 © IEC 2020 – 3 –

4.5.9 Sealing .......................................................................................................... 62

4.5.10 Climatic sequence ......................................................................................... 62

4.5.11 Damp heat, steady state ................................................................................ 62

4.5.12 Dry heat ........................................................................................................ 63

4.5.13 Mould growth ................................................................................................. 63

4.5.14 Salt mist, cyclic (sodium chloride solution) ..................................................... 63

4.5.15 Sulphur dioxide test for contacts and connections.......................................... 63

4.5.16 Fire hazard .................................................................................................... 63

4.5.17 Immersion in cleaning solvents ...................................................................... 63

4.6 Endurance test procedures ................................................................................... 63

4.6.1 Short-term endurance (load run) .................................................................... 63

4.6.2 Long-term endurance (life test) ...................................................................... 64

Annex A (normative) DC resistance test ............................................................................... 65

A.1 General ................................................................................................................. 65

A.2 Resistance values under 1 Ω – Kelvin double-bridge method ................................ 65

A.3 Resistance values from 1 Ω to many kilo-ohms ..................................................... 66

A.3.1 General ......................................................................................................... 66

A.3.2 Ammeter and voltmeter method ..................................................................... 66

A.3.3 Substitution method ....................................................................................... 67

A.3.4 Wheatstone bridge ......................................................................................... 68

A.3.5 Ohmmeter ..................................................................................................... 69

A.4 Digital ohmmeter – Resistance values from under 1 Ω to many kilo-ohms ............. 70

Annex B (normative) Dielectric voltage withstand test .......................................................... 71

Annex C (normative) Induced voltage test ............................................................................ 73

C.1 Induced voltage test .............................................................................................. 73

C.2 General test conditions ......................................................................................... 73

C.3 General test methods ............................................................................................ 73

C.4 Induced excitation voltage and frequency ............................................................. 75

C.5 Repeated induced voltage testing ......................................................................... 75

C.6 Excitation current .................................................................................................. 75

Annex D (normative) No-load loss ........................................................................................ 76

D.1 General ................................................................................................................. 76

D.2 Excitation waveform .............................................................................................. 76

D.2.1 General ......................................................................................................... 76

D.2.2 Sine-voltage (sine-flux) excitation .................................................................. 76

D.2.3 Sine-current excitation ................................................................................... 77

D.2.4 Square-wave voltage excitation ..................................................................... 77

D.3 Test method and instrumentation .......................................................................... 78

D.3.1 General ......................................................................................................... 78

D.3.2 Wattmeter ...................................................................................................... 78

D.3.3 Ammeters ...................................................................................................... 79

D.3.4 Voltmeters ..................................................................................................... 79

D.4 Test specifications and results .............................................................................. 79

Annex E (normative) Quality factor, Q .................................................................................. 80

E.1 General ................................................................................................................. 80

E.2 Accuracy ............................................................................................................... 80

E.3 Generators ............................................................................................................ 80

E.3.1 Signal generator ............................................................................................ 80

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– 4 – IEC 61007:2020 © IEC 2020

E.3.2 Pulse generator ............................................................................................. 80

E.3.3 Antenna ......................................................................................................... 80

E.4 Capacitor .............................................................................................................. 81

E.5 Measuring circuit................................................................................................... 81

E.5.1 Oscilloscope .................................................................................................. 81

E.5.2 Probe ............................................................................................................ 81

E.6 Measuring procedure ............................................................................................ 81

E.7 Calculation ............................................................................................................ 82

Annex F (normative) Electrostatic shielding ......................................................................... 84

F.1 Symbols ................................................................................................................ 84

F.2 Theoretical discussion .......................................................................................... 86

F.3 Measurement methods .......................................................................................... 87

F.3.1 Indirect method .............................................................................................. 87

F.3.2 Direct method ................................................................................................ 88

Annex G (normative) Corona test ......................................................................................... 89

G.1 Detection of corona ............................................................................................... 89

G.2 Analysis of corona ................................................................................................ 89

G.3 Test conditions and specifications ......................................................................... 90

Bibliography .......................................................................................................................... 91

Figure 1 – Pulse waveform parameters ................................................................................. 11

Figure 2 – Examples of good solder joints ............................................................................. 17

Figure 3 – Examples of defective joints ................................................................................. 18

Figure 4 – No-load current test schematic ............................................................................. 24

Figure 5 – No-load loss test schematic ................................................................................. 24

Figure 6 – Simplified diagram for short-circuit power test ...................................................... 26

Figure 7 – Circuit for measuring capacitance unbalance ....................................................... 28

Figure 8 – Circuit for determining common mode rejection ratio ............................................ 28

Figure 9 – Circuit for measuring impedance unbalance ......................................................... 29

Figure 10 – Circuit for determining cross-talk attenuation ...................................................... 30

Figure 11 – Schematic diagram of phase unbalance and amplitude unbalance ..................... 32

Figure 12 – Typical graph for determining self-capacitance ................................................... 34

Figure 13 – Circuit for determining inter-winding capacitance ............................................... 35

Figure 14 – Circuit for measurement of voltage transformation ratio ...................................... 38

Figure 15 – Circuit for measuring current transformation ratio and phase displacement ........ 39

Figure 16 – Measuring circuit of current transformation ratio and phase displacement .......... 40

Figure 17 – Circuit for determining parallel self-resonant frequency ...................................... 41

Figure 18 – Circuit for determining resonant frequency of resonant assemblies .................... 42

Figure 19 – Circuit for determination of insertion loss ........................................................... 43

Figure 20 – Use of two identical transformers when the transformation ratio is not unity

and/or a DC bias is required ................................................................................................. 44

Figure 21 – Illustration of return loss ..................................................................................... 45

Figure 22 – Basic return loss test circuit ............................................................................... 46

Figure 23 – Circuit diagram for measuring the crossover interference between two

transformer coils ................................................................................................................... 47

Figure 24 – Impulse waveform measuring circuit ................................................................... 49

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IEC 61007:2020 © IEC 2020 – 5 –

Figure 25 – Non-linearity of magnetizing current ................................................................... 50

Figure 26 – Voltage regulation test schematic ....................................................................... 51

Figure 27 – Phase (polarity) test using voltage measurement ............................................... 54

Figure 28 – Series connection method .................................................................................. 55

Figure 29 – Helmholtz structure ............................................................................................ 59

Figure A.1 – Measurement of low resistance ......................................................................... 65

Figure A.2 – Kelvin double-bridge method of measuring low resistance ................................ 66

Figure A.3 – Ammeter and voltmeter method of resistance measurement ............................. 67

Figure A.4 – Measurement of resistance by substitution........................................................ 68

Figure A.5 – Connections of Wheatstone bridge .................................................................... 68

Figure A.6 – Principle of series ohmmeter ............................................................................. 69

Figure A.7 – Digital ohmmeter method of resistance measurement ....................................... 70

Figure B.1– Typical high-potential test, showing section 1 under test .................................... 71

Figure B.2– Typical high-potential test of inductor ................................................................. 71

Figure C.1 – Block diagram of induced voltage surge test ..................................................... 73

Figure D.1 – Triangular flux-density variation in transformer core .......................................... 78

Figure D.2 – Test circuit for transformer no-load losses ........................................................ 78

Figure E.1 – Damped oscillation method ............................................................................... 80

Figure E.2 – Oscilloscope sweep for damped oscillation method ........................................... 82

Figure F.1 – Shielded single winding, core floating ............................................................... 84

Figure F.2 – Basic electrostatic symbol ................................................................................. 84

Figure F.3 – Multiple-shielded single winding, core terminal (lead) provided ......................... 84

Figure F.4 – Shielded two-winding secondary, core grounded ............................................... 85

Figure F.5 – Shielded group of windings, core floating .......................................................... 85

Figure F.6 – Multiple-shielded group of windings, core terminal (lead) provided .................... 85

Figure F.7 – Combination of shielding conditions .................................................................. 86

Figure F.8 – Typical two-winding shielded transformer .......................................................... 86

Figure F.9 – Simplified representation of Figure F.8 .............................................................. 86

Figure F.10 – Indirect measuring method for electrostatic shielding ...................................... 87

Figure G.1 – Typical circuit for corona measurement (circuit 1) ............................................. 89

Figure G.2 – Typical circuit for corona measurement (circuit 2) ............................................. 90

Table 1 – Recommended tests and specifications for specific transformer and inductor

groups .................................................................................................................................. 14

Table 2 – Voltage of dielectric withstanding voltage test ....................................................... 20

Table 3 – Sound-level corrections for audible noise tests ...................................................... 57

Table 4 – Cube dimensions, together with corresponding search coil data ............................ 60

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– 6 – IEC 61007:2020 © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
TRANSFORMERS AND INDUCTORS FOR USE IN ELECTRONIC AND
TELECOMMUNICATION EQUIPMENT –
MEASURING METHODS AND TEST PROCEDURES
FOREWORD

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