Surge Protective Device SPD Surge Protection Device · Created Date: 12/17/2017 2:13:21 AM

IEC 61 643-331

Edition 2.0 201 7-1 2

INTERNATIONAL STANDARD

Components for low-voltage surge protective devices –

Part 331 : Performance requirements and test methods for metal oxide varistors

(MOV)

IEC 61643-3

31:2017-1

2(e

n)

®

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mailto:[email protected]

IEC 61 643-331

Edition 2.0 201 7-1 2

INTERNATIONAL STANDARD

Components for low-voltage surge protective devices –

Part 331 : Performance requirements and test methods for metal oxide varistors

(MOV)

INTERNATIONAL

ELECTROTECHNICAL

COMMISSION ICS 31 .040.20

ISBN 978-2-8322-5095-2

® Registered trademark of the International Electrotechnical Commission

®

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

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– 2 – I EC 61 643-331 : 201 7 © I EC 201 7

CONTENTS

CONTENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

FOREWORD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2 Normative references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3 Terms, defi n i ti ons, symbols and abbreviated terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3. 1 Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3. 2 Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3. 3 Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 0

3. 4 Abbreviated terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1

4 Service cond i tions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1

4. 1 Operating and s torage temperature ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1

4. 2 Al ti tude or atmospheric pressure range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1

4. 3 Relati ve Hum id i ty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1

5 Mechan ical requ irements and materia ls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2

5. 1 Robustness of term inations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2

5. 2 Solderabi l i ty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2

5. 3 Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2

6 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2

6. 1 Fai lure rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2

6. 2 Test standard atmospheric cond i tions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2

7 Electrical requ i rements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2

7. 1 Nominal varistor vol tage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2

7. 2 Maximum AC (DC) conti nuous operating vol tage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3

7. 3 Standby current I DC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3

7. 4 Capaci tance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3

7. 5 Clamping vol tage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3

7. 6 Electrostatic d ischarge (ESD) (for SMD type MOV on l y) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5

7. 7 Rated impu lse energy (WTM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5

7. 8 Nominal d ischarge current In . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5

7. 9 Endurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5

7. 1 0 Lim i ted current temporary overvol tage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5

8 Standard des ign test cri teria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5

8. 1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5

8. 2 Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5

8. 2. 1 Sing le- impu lse maximum current (ITM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5

8. 2. 2 Next Impu lse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 6

8. 2. 3 Continuous rated vol tage (VM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 6

8. 3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 6

8. 3. 1 Clamping vol tage (VC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 6

8. 3. 2 Standby current (ID) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 7

8. 3. 3 Nominal varistor vol tage (VN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 7

8. 3. 4 Capaci tance (CV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 7

8. 4 Endurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 8

8. 5 ESD Test Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 8

9 Nominal d ischarge current and l im i ted curren t temporary overvol tage . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 8


I EC 61 643-331 : 201 7 © I EC 201 7 – 3 –

9 . 1 Thermal l y protected varistors – Sequence of tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 8

9. 2 Temperature and hum id i ty cycle cond i tion ing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 8

9. 3 Nominal d ischarge current I(n) test description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 9

9. 3. 1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 9

9. 3. 2 Pass/fai l cri teria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

9. 4 Lim i ted current temporary overvol tage test description and procedure for thermal l y protected varistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

9. 4. 1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

9. 4. 2 Sample preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

9. 4. 3 Test cond i ti ons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

9. 4. 4 Pass/fai l cri teria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

9. 5 Dielectric testi ng . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

9. 5. 1 Test cond i ti ons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

9. 5. 2 Setup from foi l to l eads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

9. 5. 3 Pass cri teria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Annex A ( in formative) MOV testi ng accord ing to I EC 61 643-1 1 : 201 1 – Surge protecti ve devices for the Class I , I I and I I I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

A. 1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

A.2 MOV selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

A.3 Cross reference l is t of abbreviations, descriptions and defin i tions . . . . . . . . . . . . . . . . . . . . . . . . . 25

A.4 Operating du ty test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

A.4. 1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

A.4.2 Measured l im i ti ng vol tage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

A.4.3 Class I and I I operating du ty tests (8. 3. 4. 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

A.4.4 Add i ti onal du ty test for test cl ass I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

A.4.5 Class I I I operating du ty tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

A.4.6 Pass cri teria for a l l operating du ty tests and for the add i ti onal du ty test for test class I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

A.4.7 Preferred parameters of impu lse d ischarge curren t Iimp used for C lass I add i ti onal du ty tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

A.4.8 Preferred values of impu lse d ischarge curren t In used for C lass I and Class I I res idual vo l tage and operating du ty tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

A.4.9 Preferred values of combination waveshape used for C lass I I I tests . . . . . . . . . . . . . . 34

Annex B ( in formative) I EC 61 051 Varistors for use i n e lectron ic equ ipment . . . . . . . . . . . . . . . . . . . . . . . . . 36

Annex C ( i n formative) Accelerated endurance screen ing test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

C. 1 Accelerated endurance screen ing test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

C.2 Preparation of sample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

C.3 Test cond i tions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

C.4 Pass cri teria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Annex D ( i n formative) Proposed test method for determ ination of mean time to fa i lu re (MTTF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

D. 1 Sampl ing p lans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

D.2 Total test hours . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

D.3 Samples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

D.4 I n termed iate measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

D.5 Fai lure cri teria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

D.6 Acceptance cri teria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Bibl i ography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41


– 4 – I EC 61 643-331 : 201 7 © I EC 201 7

F i gure 1 – V-I characteristic of a MOV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 0

Figure 2 – Symbol for MOV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 0

Figure 3 – Symbol for thermal l y protected MOV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1

Figure 4 – Test ci rcu i t for impu lse peak curren t clamping vol tage (VC) at peak impu lse curren t (IP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 6

Figure 5 – Test ci rcu i t for measuring l eakage current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 7

Figure 6 – Test ci rcu i t for measuring nom inal varistor vol tage (VV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 7

Figure 7 – Nom inal D ischarge Curren t F lowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 8 – Sequence of the In Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figure 9 – Temporary Overvol tage Lim i ted Current test procedure F lowchart. . . . . . . . . . . . . . . . . . . . . . . . 23

Figure A. 1 – F low chart of the operati ng du ty test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Figure A. 2 – Test set-up for operati ng du ty test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Figure A. 3 – F low chart of testi ng to determ ine the measured l im i ti ng vol tage . . . . . . . . . . . . . . . . . . . . . . . 30

Figure A. 4 – Operati ng du ty test tim ing d iagram for test classes I and I I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure A. 5 – Add i ti onal du ty test tim ing d iagram for test class I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Figure A. 6 – Operati ng du ty test tim ing d iagram for test class I I I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Figure C. 1 – Ci rcu i t of accelerated ageing test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Figure D . 1 – Test C ircu i t of MTTF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Table 1 – Vol tage ratings for d isc types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3

Table 2 – Typical Vol tage Ratings for SMD types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 4

Table A. 1 – Comparison of I EC 61 643-1 1 and I EC 61 643-31 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Table A. 2 – Preferred parameters for class I test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Table A. 3 – Preferred values for cl ass I and class I I tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Table A. 4 – Preferred values for cl ass I I I tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Table D . 1 – Sampl ing p lans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39


I EC 61 643-331 : 201 7 © I EC 201 7 – 5 –

INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________

COMPONENTS FOR LOW-VOLTAGE SURGE PROTECTIVE DEVICES –

Part 331 : Performance requirements and test methods

for metal oxide varistors (MOV)

FOREWORD

1 ) The I n ternational E lectrotechn i cal Commission ( I EC) i s a worl dwide organ i zation for standard ization compris i ng a l l n ational e l ectrotechn ical commi ttees ( I EC National Commi ttees). The object of I EC i s to promote i n ternati ona l co-operation on a l l questions concern i ng standard i zati on i n the e l ectri cal and e l ectron ic fi e l ds . To th i s end and i n add i ti on to other acti vi ti es, I EC publ i shes I n ternational Standards, Techn ical Speci fi cations, Techn ical Reports , Publ i cl y Avai l abl e Speci fi cati ons (PAS) and Gu ides (hereafter referred to as “ I EC Publ i cation (s )” ) . Thei r preparation i s en trusted to techn ical commi ttees; any I EC Nationa l Commi ttee i n terested i n the sub ject d eal t wi th may parti ci pate i n th i s preparatory work. I n ternati ona l , governmental and non -governmental organ izations l i a i s i ng wi th the I EC a l so parti ci pate i n th i s preparation . I EC col l aborates cl osel y wi th the I n ternational Organ i zation for Standard i zation ( I SO) i n accordance wi th cond i t i ons determ ined by agreement between the two organ i zati ons.

2) The formal decis ions or agreements of I EC on techn ica l matters express, as nearl y as poss i b le, an i n ternati onal consensus of opi n ion on the re l evant subjects s i nce each techn ical comm i ttee has representati on from a l l i n terested I EC National Committees.

3) I EC Publ i cations have the form of recommendations for i n ternati onal use and are accepted by I EC Nati onal Commi ttees i n that sense. Wh i l e a l l reasonable efforts are made to ensu re that the techn ical con ten t of I EC Publ i cations i s accu rate, I EC cannot be hel d respons ible for the way i n wh ich they are used or for any m i s i n terpretation by any end u ser.

4) I n order to promote i n ternational u n i form i ty, I EC Nati ona l Commi ttees undertake to app ly I EC Publ i cations transparentl y to the maximum exten t possib le i n thei r national and reg ional publ i cati ons. Any d i vergence between any I EC Publ i cation and the correspond ing nati ona l or reg i onal publ i cati on shal l be cl earl y i nd icated i n the l atter.

5) I EC i tsel f d oes not provide any attestation of conform i ty. I n dependent certi fi cati on bod ies provide conform i ty assessment services and , i n some areas, access to I EC marks of conform i ty. I EC i s not responsi ble for any services carri ed ou t by i ndependent certi fi cation bod i es .

6) Al l u sers shou ld ensure that they have the l atest ed i ti on of th i s publ i cati on .

7) No l i abi l i ty shal l attach to I EC or i ts d i rectors, employees, servants or agen ts i ncl ud ing i n d ivi dual experts and members of i ts techn ical comm i ttees and I EC National Commi ttees for any personal i n j u ry, property damage or other damage of any natu re whatsoever, whether d i rect or i nd i rect, or for costs ( i ncl ud i ng l egal fees) and expenses ari s i ng ou t of the publ i cation , use of, or rel i ance upon , th i s I EC Pub l i cation or any other I EC Publ i cations.

8) Attention i s d rawn to the Normative references ci ted i n th i s pub l i cati on . Use of the referenced publ i cations i s i nd i spensable for the correct appl i cati on of th i s publ i cation .

9) Attention i s d rawn to the possib i l i ty that some of the e l ements of th i s I EC Publ i cation may be the subject of paten t ri gh ts. I EC shal l not be hel d respons ibl e for i denti fyi ng any or a l l such paten t ri gh ts .

I n ternational Standard I EC 61 643-331 has been prepared by subcommittee 37B: Speci fic components for surge arresters and surge protecti ve devices, of I EC techn ica l committee 37: Surge arresters .

Th is second ed i ti on cancels and replaces the fi rst ed i ti on publ ished in 2003. Th is ed i tion consti tu tes a techn ical revis ion .

Th is ed i tion i ncludes the fol lowing s ign i ficant techn ical changes wi th respect to the previous ed i tion :

a) Update of the nom inal varistor vol tage test method ;

b) Add i ti on of thermal l y protected varistors – componen t symbol and test methods;

c) Add i ti on of nom inal d ischarge current – test methods;

d ) Add i ti on of vol tage ratings for d isc types (Table 1 ) ;


– 6 – I EC 61 643-331 : 201 7 © I EC 201 7

e) Add i tion of test curren ts for clamping vol tage of d i sc types (Table 2) ;

f) Add i tion of typ ical vol tage rati ngs of SMD types (Table 3) ; and

g) Add i tion of L im i ted curren t and temporary overvol tage tests for thermal l y protected varistors.

The text of th is I n ternational Standard is based on the fol lowing documents:

FDIS Report on voti ng

37B/1 60/FDIS 37B/1 64/RVD

Fu l l i n formation on the voting for the approval of th is I n ternational Standard can be found i n the report on voti ng i nd icated i n the above table.

Th is document has been drafted i n accordance wi th the I SO/IEC D irecti ves, Part 2 .

A l i st of a l l parts of I EC 61 643 series, under the general t i t l e Components for low-voltage surge protective devices, can be found on the I EC websi te.

The committee has decided that the conten ts of th is document wi l l remain unchanged un ti l the stabi l i ty date i nd icated on the I EC websi te under "h ttp : //webstore. iec.ch " i n the data re lated to the speci fic document. At th is date, the document wi l l be

• reconfi rmed ,

• wi thdrawn ,

• replaced by a revised ed i ti on , or

• amended .

A b i l ingual vers ion of th is publ ication may be issued at a l ater date.

IMPORTANT – The 'colour inside' logo on the cover page of th is publ ication ind icates that i t contains colours which are considered to be usefu l for the correct understand ing of i ts contents. Users shou ld therefore print th is document using a colour printer.


http://webstore.iec.ch/

I EC 61 643-331 : 201 7 © I EC 201 7 – 7 –

COMPONENTS FOR LOW-VOLTAGE SURGE PROTECTIVE DEVICES –

Part 331 : Performance requirements and test methods for metal oxide varistors (MOV)

1 Scope

This part of I EC 61 643 i s a test speci fication for metal oxide varistors (MOV), wh ich are used for appl ications up to 1 000 V AC or 1 500 V DC i n power l i ne, or te lecommunication , or s ignal l i ng ci rcu i ts . They are des igned to protect apparatus or personnel , or both , from h igh trans ien t vol tages.

Th is speci fication appl ies to MOVs having two e lectrodes and hybrid overvol tage protection components . Th is speci fication a lso does not appl y to mountings and the ir effect on the MOV’s characteristics . Characteristics g i ven appl y solel y to the MOV mounted on l y i n the ways described for the tests.

2 Normative references

The fol l owing documents are referred to i n the text i n such a way that some or a l l of thei r con ten t consti tu tes requ irements of th is document. For dated references, on l y the ed i tion ci ted appl i es. For undated references, the latest ed i tion of the referenced document ( includ ing any amendments) appl i es.

I EC 60068-1 : 201 3, Environmental testing – Part 1 : General and guidance

I EC 60068-2-20:2008, Environmental testing – Part 2-20: Tests – Test T: Test methods for solderability and resistance to soldering heat of devices with leads

I EC 60068-2-21 : 2006, Environmental testing – Part 2-21: Tests – Test U: Robustness of terminations and integral mounting devices

I EC 60068-2-78: 201 2, Environmental testing – Part 2-78: Tests – Test Cab: Damp heat, steady state

I EC 61 643-1 1 : 201 1 , Low-voltage surge protective devices – Part 1 1 : Surge protective devices connected to low-voltage power systems – Requirements and test methods

I EC 61 000-4-2 : 2008, Electromagnetic compatibility (EMC) – Part 4-2: Testing and measurement techniques – Electrostatic discharge immunity test

3 Terms, defin i tions, symbols and abbreviated terms

For the purposes of th is document, the fol l owing terms, defin i tions, symbols and abbreviated terms appl y.

I SO and I EC main tain term inolog ical databases for use in standard ization at the fol l owing addresses:

• I EC E lectroped ia: avai lable at h ttp : //www.electroped ia. org /

• I SO On l ine browsing p latform : avai l able at h ttp: //www. iso.org/obp


http://www.electropedia.org/

http://www.iso.org/obp

– 8 – I EC 61 643-331 : 201 7 © I EC 201 7

3. 1 Ratings

3. 1 . 1 absolute maximum ratings l im i ting va lues of operating and envi ronmenta l cond i tions appl icable to a component, device, equ ipment or mach ine as defined by i ts publ ished speci fication data, wh ich shou ld not be exceeded under the worst poss ib le cond i ti ons

Note 1 to en try: A l im i ti ng cond i ti on may be e i ther a maximum or a m in imum or both .

[SOURCE: MODIFIED: I EC 62240-1 : 201 3, Clause 3. 1 . 1 , mod i fied ( "any sem iconductor device of a speci fic type" replaced by "a component, device, equ ipment or mach ine" , add i ti on of Note 1 to entry) ]

3. 1 .2 s ing le-impu lse [transient] maximum current ITM

rated maximum value of current wh ich may be appl ied for a s i ng le impu lse of speci fied waveform

Note 1 to en try: For power d i stri bu tion su rge protecti ve devices (SPDs), I EC 61 643-1 1 , Maximum Discharge Curren t I

MAX i s used .

3. 1 .3 nominal d ischarge current In

crest va lue of the curren t through the MOV having a current waveshape of 8/20

3.1 .4 impu lse l i fe characteristic graph ica l represen tation between impu lse curren t peak ( I) , equ iva len t rectangu lar pu lse wid th (T) , and impu lse numbers (n ) for wh ich the varistor can wi thstand

Note 1 to en try: Un l ess otherwise speci fi ed , the range of T shal l be 20 µ s to 1 0 ms, the range of n shal l be 1 06 , 1 05 , 1 04 , 1 03 , 1 02 , 1 0 1 and 1 00 temperatu re derati ng cu rve.

3. 1 .5 temperature derating curve

graph ica l representation of parameter derating against temperature

Note 1 to en try: Typical parameters are rated vo l tage, impu lse cu rren t, energy and average power d i ss ipati on .

3. 1 .6 s ing le-pu lse [transient] maximum energy WTM

rated maximum value wh i ch may be absorbed for a s i ng l e pu lse of a speci fi ed waveform

Note 1 to en try: Un l ess otherwise speci fi ed , 2 ms rectangu l ar pu l se i s used ( I EC 60060).

3. 1 .7 maximum continuous vol tage VM

vo l tage that may be appl ied con tinuous l y at a speci fi ed temperature

Note 1 to en try: May a l so be cal l ed UC or maximum con ti nuous operati ng vol tage (MCOV).

Note 2 to en try: See F igure 1 .


I EC 61 643-331 : 201 7 © I EC 201 7 – 9 –

3. 1 .8 maximum continuous AC vol tage VM(AC)

va lue of rms. power frequency vol tage ( l ess than 5 % tota l harmon ic d is tortion ) that may be appl ied conti nuous l y at a speci fi ed temperature

3. 1 .9 maximum continuous DC vol tage VM(DC)

DC vol tage that may be appl ied con tinuous l y at a speci fied temperature

3. 1 . 1 0 Mean Time To Fai lu re MTTF basic measure of rel i ab i l i ty for non-repai rable i tems, the tota l number of l i fe un i ts of an i tem d ivided by the tota l number of fai l u res wi th in that popu lation , du ring a parti cu lar measurement i n terval under stated cond i ti ons

3.2 Characteristics

3.2. 1 characteristic i nherent and measurable property of an MOV

3.2.2 standby current ID curren t passing th rough MOV at maximum con tinuous vol tage VM

Note 1 to en try: The cu rren t passing th rough the MOV at l ess than VM i s cal l ed l eakage curren t.

3.2.3 nominal varistor vol tage VN

vo l tage across the MOV measured at a speci fi ed curren t of speci fic duration


3.2.4 clamping vol tage VC peak vol tage across the MOV measured under cond i tions of a speci fied peak pu lse current (IP) and speci fied waveform


Note 2 to en try: U n less otherwise speci fi ed , a typical val ue of th i s parameter i s measu red wi th a pu l sed cu rrent 8/20 waveform .

Note 3 to en try: Clamping vo l tage, VC, i s referred to as Measured Lim i ti ng Vol tage i n I EC 61 643-1 1 .

3.2.5 capaci tance CV

capaci tance across the MOV measured at a speci fi ed frequency, vol tage and time

3.2.6 metal oxide varistor MOV component whose conductance, at a g iven temperature, i ncreases rapid l y wi th vol tage

Note 1 to en try: Th i s i s a l so known as a vol tage dependant res i stor (VDR).


– 1 0 – I EC 61 643-331 : 201 7 © I EC 201 7

3.2.7 thermal ly protected metal oxide varistor varistor wh ich i ncludes a series non-resettable e lement that wi l l d isconnect the MOV when i t i s overheated due to excess ive d iss ipation

Figure 1 – V-I characteristic of an MOV

3.3 Symbols

Figures 2 and 3 represent the I EC 6061 7 symbols for MOV and thermal l y protected MOV, respectivel y.

Figure 2 – Symbol for MOV

IEC

-v +v

- i

+ i

ITM

Ip

INID

VM

VVV

C

IEC

U


I EC 61 643-331 : 201 7 © I EC 201 7 – 1 1 –

Figure 3 – Symbol for thermal ly protected MOV

NOTE I EC 60027 recommends the l etters V and v on l y as reserve symbols for vol tage; however, i n the fi e l d of MOV components, these are so widel y used that i n th i s publ i cation they are preferred to U and u .

3.4 Abbreviated terms

DUT Device Under Test

ESD E lectrostatic D ischarge

MCOV Maximum Continuous Operating Vol tage

MOV Metal Oxide Varistor

MTTF Mean Time To Fai l ure

SMD Surface Mount Device

SPD Surge Protecti ve Device

VDR Vol tage Dependent Resistor

4 Service condi tions

4.1 Operating and storage temperature ranges

Operating range

– Normal : –5 °C to +55 °C

– Extended : −40 °C to +85 °C

Storage range MOV

– Normal : –40 °C to +85 °C

– Extended : −40 °C to +1 25 °C

Storage range thermal l y protected MOV

– Normal : –40 °C to +85 °C

– Extended : −40 °C to +85 °C

4.2 Al ti tude or atmospheric pressure range

The a l ti tude of a i r pressure is wi th in 80 kPa to 1 06 kPa (refer to I EC 60068-1 ).

4.3 Relative Humidi ty

Normal range: 5 % to 95 % at 25 °C (refer to I EC 60068-1 and I EC 60068-2-78) .

IEC

U

θ

Mon i tor l ead


– 1 2 – I EC 61 643-331 : 201 7 © I EC 201 7

5 Mechanical requirements and materials

5.1 Robustness of terminations

I f appl icable, the user shal l speci fy a su i table test from I EC 60068-2-21 .

5.2 Solderabi l i ty

Solder term inations shal l meet the requ i rements of I EC 60068-2-20, test Ta, method 1 .

5.3 Marking

Leg ible and permanent marking shal l be appl i ed to the MOV as necessary to ensure that the user can determ ine the fo l l owing i n formation by i nspection :

Each MOV shal l be marked wi th the fol lowing i n formation :

Date of manufacture or batch number

Manufacturer name or trademark

Part number

Safety approval markings

NOTE 1 The necessary i n formation can a l so be coded .

When the space i s not sufficien t for pri n ti ng th is data, i t shou ld be provided i n the techn ical documentation after agreement between the manu facturer and the purchaser.

6 General

6.1 Fai lu re rates

Sampl ing s i ze, e l ectrical characteristics to be tested , etc. shou ld be covered by the qual i ty assurance requ i rements, wh ich are not covered by th is document.

6.2 Test standard atmospheric conditions

The fol l owing tests shal l be performed on the MOVs as requ i red by the appl ication . Un less otherwise speci fied , ambien t test cond i tions shal l be as fo l l ows:

• temperature: 1 5 °C to 35 °C;

• re lati ve hum id i ty: 25 % to 75 %;

MOVs of various types shou ld have the characteristics l i sted i n Table 1 when tested i n accordance wi th C lause 8.

7 Electrical requirements

7. 1 Nominal varistor vol tage

When tested accord ing to 8 . 3 . 3, varistor vol tage shou ld be wi th in the speci fi ed manufacturer’s l im i ts. Table 1 shows the nom inal varistor vol tages of h igh vol tage and l ow vol tage d isc types that are commonl y used ; the ir a l lowable to lerances are ±1 0 %.

The nom inal varistor vol tages and tolerances l i s ted i n Table 2 are typical for surface mount Device (SMD) types.


I EC 61 643-331 : 201 7 © I EC 201 7 – 1 3 –

7.2 Maximum AC (DC) continuous operating vol tage

Un less otherwise speci fi ed , MOVs shal l have a maximum AC (DC) con tinuous vol tage VM(AC) /VM(DC) as g i ven i n Tables 1 and 2 , the conform ity shal l be evaluated accord ing to 8. 2 . 3.

NOTE Maximum AC (DC) con ti nuous operati ng vol tage i s sometimes referred to as UC.

7.3 Standby current IDC

When tested accord ing to 8. 3. 2 , the standby current, DC, under maximum continuous DC vol tage VDC , sha l l be less than the maximum value speci fi ed by the manufacturer and there shal l be no upward dri fting during the appl ication of the test vol tage VDC .

7.4 Capacitance

When tested accord ing to 8. 3. 4, the measured value of capaci tance shal l not exceed the va lue speci fied by the manufacturer.

7.5 Clamping vol tage

The measured clamping vol tage (see 8. 3 . 1 ) at a speci fied impu lse curren t shal l be no more than the speci fi ed values or the values ind icated i n Tables 1 and 2 . Un less otherwise speci fied , 8/20 impu lse curren t having the peak as speci fied in shal l be used .

NOTE Clamping vo l tage VC i s referred to as Measured Lim i ti ng Vol tage i n I EC 61 643-1 1 .

Table 1 – Typical vol tage ratings for d isc types

Nominal vari stor vol tage V

N (V)

Max. continuous vol tage (VM) Clamping vol tage (Note) , V

C (V)

AC (rms) VM(AC)/VM(DC) DC VDC

8 /20, VC

1 8 1 1 1 4 36

22 1 4 1 8 43

27 1 7 22 53

33 20 26 65

39 25 31 77

47 30 38 93

56 35 45 1 1 0

68 40 56 1 35

82 50 65 1 35

1 00 60 85 1 65

1 20 75 1 00 200

1 50 95 1 25 250

1 80 1 1 5 1 50 300

200 1 30 1 70 340

220 1 40 1 80 360

240 1 50 200 395

275 1 75 225 455

300 1 95 250 505

330 21 0 270 545

360 230 300 595

390 250 320 650

430 275 350 71 0


– 1 4 – I EC 61 643-331 : 201 7 © I EC 201 7

Nominal vari stor vol tage V

N (V)

Max. continuous vol tage (VM) Clamping vol tage (Note) , V

C (V)

AC (rms) VM(AC)/VM(DC) DC VDC

8 /20, VC

470 300 385 775

51 0 320 41 0 845

560 350 450 930

620 385 505 1 025

680 420 560 1 1 20

71 5 440 585 1 1 80

750 460 61 5 1 240

820 51 0 670 1 355

91 0 550 745 1 500

1 000 625 825 1 650

1 1 00 680 895 1 81 5

1 200 750 970 2 000

1 600 1 000 1 280 2 650

1 800 1 1 00 1 465 2 970

NOTE Clamping vo l tage VC i s referred to as Measured Lim i ti ng Vol tage i n I EC 61 643-1 1 .

Table 2 – Typical vol tage ratings for SMD types

Nominal vari stor

Vol tage VN(V)

Maximum continuous vol tage (VM)

AC (rms) VAC

DC VDC

5, 6 ± 20 % 2 , 5 4

6 , 8± 20 % 3, 5 4 , 5

8 , 2 ± 20 % 4 5, 5

1 0 ± 20 % 5 7

1 2± 20 % 6 8 , 5

1 5± 20 % 7, 5 1 0, 5

1 8 ± 20 % 9 1 3

22 ± 1 0 % 1 4 1 8

27 ± 1 0 % 1 7 22

33 ± 1 0 % 20 26

39 ± 1 0 % 25 31

47 ± 1 0 % 30 38

56 ± 1 0 % 35 45

68 ± 1 0 % 40 56

82 ± 1 0 % 50 65

NOTE Clamping vol tage VC i s referred to as Measu red Lim i ti ng Vol tage i n I EC 61 643-1 1 .

During the tests , there shal l be no fl ashover or puncture of the samples, the MOV vol tage of the samples shal l be tested prior to and after the tests, the change of wh ich shal l not exceed ±1 0 % , when tested accord ing to 8. 3. 3 .


I EC 61 643-331 : 201 7 © I EC 201 7 – 1 5 –

7.6 Electrostatic d ischarge (ESD) (for SMD type MOV on ly)

The SMD MOVs shal l be subjected to electrostati c d ischarge (ESD) con tact d ischarge test of 8 kV for 1 0 appl ications wi th an i n terval of 1 s accord ing to 8 . 5.

During the tests , there shal l be no evidence of flashover or puncture of the samples, and the Varistor vol tage of the samples shal l be tested prior to and after the tests, the change of wh ich shal l not exceed ±30 % .

7.7 Rated impu lse energy (WTM )

The MOV shal l be capable of absorbing the impu lse energy speci fied by the manufacturer when subjected to one impu lse current of 2 ms or 1 0/1 000 wave and tested accord ing to 8. 2. 1 .

7.8 Nominal d ischarge current In

The MOV shal l be subjected to 1 5 appl ications of impu lse currents of 8/20 wave wi th the peak speci fied by the manufacturer, and tested accord ing to 9 . 3 .

7.9 Endurance

The MOV used for power suppl y ci rcu i try shal l be subj ected to an endurance test under the cond i tions of maximum operati ng temperature and maximum continuous operating vol tage for 1 000 h and tested accord ing to 8. 4.

I f a l l concerned parties agree the optional accelerated endurance screen ing test i n Annex C may be used .

7. 1 0 Lim ited current temporary overvoltage

Th is i s an AC step stress test to evaluate MOV componen ts for poten tia l i gn i ti on sou rces when the component i s subj ected to a. c. overload , (see 9 . 4) .

8 Standard design test cri teria

8. 1 General

The des ign tests described i n 8 . 3 provide s tandard ized methods for measuring speci fi ed characteristics of a MOV for the purpose of component selection for a surge protecti ve device (SPD). These characteristics may vary from MOV to MOV, making i t necessary to measure a l l components to be se lected for a SPD. MOVs are bi -d i rectional and they shal l be tested wi th both pos i ti ve and negative vol tages.

8.2 Ratings

8.2. 1 Single-impulse maximum current (ITM )

I n the absence of speci fi ed requ i rements , the test current shal l be an 8/20 waveshape.

NOTE See F igure 4 .


– 1 6 – I EC 61 643-331 : 201 7 © I EC 201 7

Components

C Energy storage capaci tor R3 Impu lse-shapi ng res i stor

L I mpu lse-shapi ng i nductor R2 Impu lse-shapi ng and cu rren t-l im i ti ng res i stor

MOV Device under test (MOV) R4 Current-sens ing res i stor (coaxi al ). Al terna-ti vel y, a cu rrent transformer probe of adequate rati ng may be used

OSC Osci l l oscope for observing current and vol tage

S1 Charg i ng swi tch

PS DC charg i ng power suppl y S2 Di scharge swi tch

R1 Charg i ng res i stor

Cauti on : The ci rcu i t shown i s for descri pti on on l y; Measurement techn iques for h i gh -current and h i gh -frequency testi ng shou ld be observed , such as four-poin t Kel vin con tact, d i fferential osci l l oscope, short l eads, etc.

Figure 4 – Test ci rcu i t for s ing le-impulse maximum current

8 . 2.2 Next Impulse

The next impu lse shal l be appl i ed after the device under test (DUT) has returned to thermal equ i l ibrium (for example, the i n i tia l cond i tions before the impu lses were appl ied ). I n the absence of speci fi ed requ i rements, the test current shal l be an 8/20 waveshape.

NOTE 1 MOVs i n tended for service i n I EC 61 643-1 1 su rge protecti ve devices requ i re specia l cl ass I , cl ass I I and cl ass I I I testi ng procedures and waveforms. These tests are covered i n Annex A.

NOTE 2 See F i gu re 4 .

8.2.3 Continuous rated vol tage (VM )

Th is rati ng i s veri fied i n 8 . 3 . 2 .

8.3 Electrical characteristics

8.3. 1 Clamping vol tage (VC)

Maximum clamping vol tage shal l be measured during the s i ng le impu lse cu rrent ( IC) , see clause 8 . 2. 1 . The peak clamping vol tage and peak test curren t are not necessari l y coinciden t i n time. I n the absence of speci fied requ i rements, the test current sha l l be an 8/20 waveshape.

NOTE 1 MOVs i n tended for service i n I EC 61 643-1 1 su rge protecti ve devices requ i re special cl ass I I or cl ass I I I testi ng procedures and waveforms. These tests are covered i n Annex A.

NOTE 2 See F i gu re 4 .

IEC

OSC V I

V MOV

R2

R4 R3

L S2 S1 R1

PS C


I EC 61 643-331 : 201 7 © I EC 201 7 – 1 7 –

8.3.2 Standby current (ID)

I n th is measurement, vo l tage shou ld be main tained at a steady value regard less of the load impedance. A power suppl y of constan t vol tage source shou ld be used . I t i s not recommended that the vol tmeter be connected across the DUT due to the cu rrent b leed ing th rough the meter. The l eakage current read ing wou ld be i naccurate. The Vol tage suppl ied PS shou ld be set to the speci fi ed Maximum Continuous Operating Vol tage VM(DC) of the MOV under test.

NOTE See F igure 5.

Components

A Curren t meter

PS Vol tage source (DC)

V Vol tmeter

Figure 5 – Test ci rcu i t for measuring l eakage current

8 .3.3 Nominal varistor vol tage (VN )

I n th is measurement, cu rrent shou ld be maintained at a steady value regard less of the load impedance. A power suppl y of constant current source shou ld be used . The time of appl i ed test current (IN ) shal l be between 1 0 to 1 00 ms. Un less otherwise speci fi ed , the test curren t

shal l be 1 mA DC.

NOTE See F igure 6 .

Components

A Curren t meter

P B ipolar pu l sed cu rrent sou rce

V Vol tmeter

Figure 6 – Test ci rcu i t for measuring nominal varistor vol tage (VN )

8. 3.4 Capaci tance (CV)

This shou ld be measured at a speci fi ed s i nusoida l frequency and vol tage at a speci fied

temperature. Un less otherwise speci fi ed , a s ignal of 0 , 1 V rms. of 1 kHz at 25 °C is recommended .

IEC

V V

A

P

IEC

V V

MOV

A

PS


– 1 8 – I EC 61 643-331 : 201 7 © I EC 201 7

8.4 Endurance

The nom inal varistor vol tage VN and the l eakage curren t of the samples are measured and

recorded prior to th is test.

The MOV is heated to the maximum operating temperature of 1 00 ºC un less otherwise

speci fied for the duration of 1 000 h .

The test vol tage shal l be VM (AC) for AC and /or VM (DC) for DC .The test shou ld be performed in

a chamber, at a temperature that sha l l be main tained wi th in 5 oC. When the test i s fin ished , the samples shou ld be cooled down for not l ess than 1 h nor more than 2 h . The nom inal varistor vol tage, VN , and the l eakage current shou ld be wi th in the speci fied l im i ts when

measured at ambient temperature.

8.5 ESD Test Method

I n i tia l measurements: Varistor vol tage and clamping vol tage.

The samples shal l be moun ted on a ci rcu i t board wi th a l arge ground p lane. The ci rcu i t board shal l have a conven ient d ischarge poin t for the ESD gun i n con tact mode and the SMD shal l be moun ted between the ESD gun d ischarge poin t and the board ground . The ci rcu i t board i s then p laced at the cen ter of a m in imum 0, 5 m metal ground plane as described in ANSI /ESD SP5. 6. The ground plane of the ci rcu i t board and the metal l ic g round plane shal l make good e lectrical con tact.

The samples shal l be subjected to the test us ing the con tact d ischarge method at 8 kV ± 5 % for 1 0 appl ications us ing an I EC 61 000-4-2-compl ian t ESD gun . The ground strap of the ESD gun shal l be connected to a corner of the meta l g round plane. During and after the test, there shal l be no evidence of fl ashover or puncture of the samples.

9 Nominal d ischarge current and l imi ted current temporary overvol tage

9. 1 Thermal ly protected varistors – Sequence of tests

• Temperature hum id i ty and cond i ti on ing 9 . 2

• D ie lectric test 9 . 5

• Nom inal d ischarge current testi ng as described i n 9 . 3

• L im i ted current test as speci fi ed i n 9 . 4

• D ie lectric test 9 . 5

9.2 Temperature and humid i ty cycle condition ing

The samples shal l be subj ected to three complete cond i tion ing cycles. Each cycle shal l consist of 24 h at 85 °C fol lowed immed iatel y (wi th in 1 5 m in) by at l east 24 h at (35 ± 5) °C and (90 ± 5) % re lati ve hum id i ty, fo l l owed by 8 h a t (0 ± 2 ) °C.

NOTE The d i el ectri c and i n su lation res i stance tests are performed after removal of the samples from the cond i ti on ing chamber.


I EC 61 643-331 : 201 7 © I EC 201 7 – 1 9 –

9.3 Nominal d ischarge current I(n ) test description

9.3. 1 General

Figu re 7 shows the test sequence compris ing of:

Before surge test, measure i n i tia l nom inal varistor vol tage and standby cu rren t.

Appl y 1 surge wi th no MCOV, and wi th in 1 second (T1 F igure 8) , appl y MCOV for 60 s ± 1 5 s (T2 F igure 8).

Repeat th is cycle 1 5 times.

After each 5 cycles, the component shou ld be a l l owed to cool for 30 m in ± 5 m in (T3 F igure 8)

After the l ast cycle, continue to apply MCOV for at l east an add i tional 1 5 m in (T4 F igure 8) .

Measure nom inal varistor vol tage and standby curren t.

Caution , some of the tests speci fied can be hazardous to the persons carrying them out; a l l appropriate measures to protect personnel against poss ib le fi re or explosive hazards shou ld be taken .


– 20 – I EC 61 643-331 : 201 7 © I EC 201 7

Figure 7 – Nominal Discharge Current F lowchart

IEC

Nominal discharge

current testing for

varistors

Measure initial

nominal varistor

voltage and

leakage current Appl ied in +1 0 %, –0 %

Declared in

Surge count = 0

Surge group

count = 0

Apply 1 positive

polarity 8/20 surge

of rated In, without

AC power

Surge count =

surge count + 1

Within 1 second

apply AC power at

MCOV value

Apply the AC

power for

60 s ± 1 5 s

Within 1 minute

apply 1 positive

polarity 8/20 surge

of rated In without

AC power

Surge count =

surge count + 1

Is surge

count < 5? Yes

No

Surge group

count = surge

group count + 1

Al low test sample

to rest for

30 minutes ±

5 minutes

Is

surge group

count < 3?

Yes

No

Apply MCOV for at

least 1 5 minutes

Measure final

nominal varistor

voltage and

standby current

Nominal

varistor voltage

within ±1 0 %

of initial?

Yes

No

FAIL

Leakage current

≤ manufacturer's

specification?

Yes

No

FAIL

If thermally

protected varistor is

being tested, has thermal

link functioned?

Yes

FAIL

No

PASS


I EC 61 643-331 : 201 7 © I EC 201 7 – 21 –

Figure 8 – Sequence of the In Test

9.3.2 Pass/fai l cri teria

The measured varistor vol tage after 1 5 cycles shou ld be not l ess than 90 % of the i n i ti a l measured nom inal varistor vol tage and the l eakage curren t shou ld be less than the manufacturer’s speci fied value.

9.4 Limited current temporary overvoltage test description and procedure for thermal ly protected varistors

9.4. 1 General

For thermal l y protected varistors in tended to be i nstal l ed i n permanen tl y connected appl ications, the l im i ted curren ts tested shal l be 0 , 625 A, 1 , 25 A, 2 , 5 A, 5, 0 A and 1 0, 0 A un less otherwise speci fi ed . For thermal l y protected varistors i n tended to be i nstal led i n cord connected appl ications, the l im i ted curren ts tested shal l be 0, 625 A, 1 , 25 A, 2 , 5 A and 5, 0 A un less otherwise speci fi ed .

Caution , some of the tests speci fied can be hazardous to the persons carrying them out; a l l appropriate measures to protect personnel against possib le fi re or explos ive hazards shou ld be taken .

9.4.2 Sample preparation

The varistor sha l l be mounted in accordance wi th the manufacturer’ s recommendations. Cheesecloth is used for hazard mon i toring . Two l ayers of cheesecloth shal l be wrapped around the componen t at a d istance of 1 0 mm from the component body form ing a component enclosure.

9.4.3 Test condi tions

Adjust an AC power suppl y to 1 , 6 times the speci fied rated vol tage of the device at each perspective curren t accord ing to F igure 9 . Mon i tor the curren t of the device under test from the time the power i s appl ied un ti l the thermal l i nk opens but not l onger than 7 hours. After the thermal l i nk has opened a l l ow the device under test to cool for 5 m inu tes.

IEC MCOV T2

T1

T3 T3 T4

Surge

T1 ≤ 1 second

T2 = 60 seconds ± 1 5 seconds

T3 = 30 m inu tes ± 5 m inu tes

T4 ≥ 1 5 m inu tes


– 22 – I EC 61 643-331 : 201 7 © I EC 201 7

9.4.4 Pass/fai l cri teria

After the test the cheesecloth shal l be exam ined . The cheesecloth shal l not be damaged by any of the fol l owing hazards; e jection of fragments, e j ection of mol ten materia ls , production of hot gases (wh ich i ncludes flames) and e lectrical sparking . The component mounting posi ti on shal l not be changed by any solder reflow.

The cheesecloth shal l be cotton and have a m in imum of 1 3 threads by 1 1 threads i n any square centimeter.


I EC 61 643-331 : 201 7 © I EC 201 7 – 23 –

Figure 9 – Temporary Overvoltage Limited Current test procedure Flowchart

IEC

Thermal overload test for

thermally protected varistors

What is declared rating of

thermally protected varistor?

1 0 A

5 A

Thermal overloal sequence = 1 ,25 A,

2,5 A, 5,0 A, 1 0,0 A

Thermal overloal sequence = 0,625 A,

1 ,25 A, 2,5 A, 5,0 A

Adjust A-C power

supply open circuit

for 1 ,6 times rated

varistor voltage

Adjust A-C power

supply for short

circuit current

Connect new sample

across power supply

unti l the thermal

disconnect operates or

unti l thermal stabil ity is

reached

Yes

No Has

thermal

disconnect

operated?

Has

thermal

stabi l i ty been

reached?

No

Yes

End of sequence? No

Yes

Pass Pass

Fai l Fai l

Pass End

Test dielectric See section 9.3.1 for

Pass/Fail criteria

Go to next

test current

in sequence


– 24 – I EC 61 643-331 : 201 7 © I EC 201 7

9.5 Dielectric testing

9.5. 1 Test conditions

Set the d ie lectric test equ ipment as fol l ows:

Vol tage = 2 times the rated vol tage of the device under test.

Threshold Current = Vol tage / 200 kΩ

Measure the d ielectric strength across the thermal l i nk for 1 m inu te.

9.5.2 Setup from foi l to leads

Set the d ie lectric test equ ipment as fol lows:

Vol tage = 2 times the rated vol tage of the device under test + 1 000 V

Threshold Current = Vol tage / 2 000 kΩ

Wrap a piece of foi l around the componen t being carefu l to have a gap of at least 0 , 5 mm between the foi l and the l eads.

Tie the leads of the component together and connect the d ie lectric tester across the foi l and the l eads.

Measure the d ielectric s treng th between the leads and the foi l for 1 m inu te.

9.5.3 Pass cri teria

No current greater than threshold curren t.

NOTE Vol tage i s an rms. vol tage, s i ne wave of 45 to 62 Hz.


I EC 61 643-331 : 201 7 © I EC 201 7 – 25 –

Annex A (informative)

MOV testing according to IEC 61 643-1 1 : 201 1 –

Surge protective devices for the Class I , I I and I I I

A.1 General

Surge protecti ve devices (SPDs) compl ian t to I EC 61 643-1 1 meet one or more defi ned impu lse tests. These tests are termed: class I , class I I and class I I I .

The Class I test i s i n tended to s imu late partia l conducted l i ghtn ing current impu lses. SPDs subj ected to Class I test methods are general l y recommended for l ocations at poin ts of h i gh exposure, e . g . , l i ne entrances to bu i ld i ngs protected by l igh tn ing protection systems.

SPDs tested to Class I I or I I I test methods are subjected to impu lses of shorter duration .

Fu l l testi ng deta i l s are con tained i n I EC 61 643-1 1 . Th is annex g i ves an overview of MOV testing for use in I EC 61 643-1 1 compl ian t SPDs.

A.2 MOV selection

I EC 61 643-1 1 SPD impu lse ratings may be met wi th a s ing le MOV or by combinations of MOVs connected i n series or para l le l or both .

A.3 Cross reference l ist of abbreviations, descriptions and defin i tions

Table A. 1 provides the l i st of abbreviations, descriptions and defin i tions used i n th is document re lated to the standard I EC 61 643-1 1 .


– 26 – I EC 61 643-331 : 201 7 © I EC 201 7

Table A. 1 – Comparison of IEC 61 643-1 1 and IEC 61 643-31 1

IEC 61 643-1 1 IEC 61 643-331

Abbrevi -ation

Description Defin i tion/Clause

Abbrevi -ation

Description (parametric terms)

Defin i tion/Clause

Abbreviations, descriptions and defin i tions related to vol tage

UC Maximum conti nuous

operati ng vol tage 3. 1 . 1 1 V

M Maximum conti nuous vol tage 3. 1 . 7

3 . 1 . 6. 1

3 . 1 . 6. 1

UOC

Open ci rcu i t vol tage of the combination wave generator

3 . 1 . 23

Ures

Residual vol tage 3. 1 6 VC C l amping vol tage 3. 2 . 3

Lim i ti ng vol tage wi th the combination wave

VC C l amping vol tage 3. 2. 3

Measured l im i ti ng vol tage 3 . 1 . 1 5 VC C l amping vol tage 3. 2. 3

Abbreviations, descriptions and defin i tions related to current

In Nom inal d i scharge curren t for

cl ass I I test 3 . 1 . 9 I

n Nom inal d i scharge current 3 . 1 . 3

Imax

Maximum d i scharge cu rren t 3 . 1 . 48

Ii mp

I mpu l se d i scharge curren t for cl ass I test

3 . 1 . 1 0

If Fol l ow curren t 3 . 1 . 1 2

Ip Prospecti ve short-ci rcu i t

current of a power suppl y 3 . 1 . 38

Defin i tions related to impu lse test cl assi fication

Class I tests 3 . 1 . 34. 1

Class I I tests 3. 1 . 34. 2

Class I I I tests 3. 1 . 34. 2

A.4 Operating duty test

A.4. 1 General

An overview is g i ven in the fl ow chart for the operati ng du ty test i n F igure A. 1 .


I EC 61 643-331 : 201 7 © I EC 201 7 – 27 –

OPERATING DUTY TEST IN IEC 61 643-1 1 : 201 1

Operating duty test 8.3.4

Fol low current

See 7.1 .1 d2)

(Annex C.2)

Characteristics

of source

in 8.3.4.2.1

Characteristics

of source

in 8.3.4.2.2

What

is the test

class?

Determine the measured

l imiting voltage in 8.3.3

Operating duty

test

in 8.3.4.3

Operating duty

test

in 8.3.4.3

or 8.3.4.5

500 A or less Above 500 A

Test class I Test class I I and I I I

Additional duty

test

in 8.3.4.4

Pass criteria

in 8.3.4.6

Test completed

NA for MOVs

NA - Not applicable

NOTE:

Measured l imiting voltage in IEC 61 643-1 1 is referred as clamping voltage Vc in I EC 61 643-331

IEC

Figure A. 1 – Flow chart of the operating duty test

This is a test i n wh ich service cond i tions are s imu lated by the appl ication of a s tipu lated number of speci fied impu lses to the SPD wh i le i t i s energ ized at the maximum continuous operating vol tage UC vi a an AC source accord ing to 8. 3 . 4 . 2 .

Th is test setup shal l comply i n wi th the ci rcu i t d i agram g iven i n F igure A.2 .


– 28 – I EC 61 643-331 : 201 7 © I EC 201 7

Key

UC: power frequency sou rce accord ing 8. 3. 4. 2

D: SPD d i sconnectors, as speci fi ed by the manufactu rer

DUT: Device under test (SPD)

Surge: 8/20 cu rren t for Class I and I I operati ng d u ty test accord ing 8 . 3 . 4 . 3

I mpu lse d i scharge curren t Ii mp

for add i ti onal du ty test accord i ng 8 . 3 . 4. 4

Combinati on wave for Class I I I operati ng d u ty test accord ing 8 . 3 . 4 . 5

Figure A.2 – Test set-up for operating duty test

The power frequency source characteristics for the operating du ty test for SPDs wi th fol l ow curren t 500 A or l ess is described i n 8. 3 . 4 . 2 . 1 .

The measured l im i ti ng vol tage shal l be determ ined us ing the test described i n 8. 3. 3 .

To avoid overstress of the samples, the test i s performed:

• accord ing to 8 . 3 . 3 . 1 , bu t on l y at a crest va lue correspond ing to Iimp for test class I

• accord ing to 8 . 3 . 3 . 1 , bu t on l y at In for test class I I

• accord ing to 8 . 3 . 3 . 3, bu t on l y at UOC for test class I I I

wi th one pos i ti ve and one negative surge appl ied .

A.4.2 Measured l imiting vol tage

A.4.2. 1 General

The tests on the d i fferent SPD types to determ ine thei r measured l im i ti ng vol tages shal l be performed accord ing to the fl ow chart i n F igure A. 3.

A.4.2.2 Residual vol tage wi th 8/20 current impulse (8.3.3.1 )

I f the SPD con ta ins on l y vol tage- l im i ting components , th is test needs on l y to be performed at crest va lues of Iimp for test class I or In for test cl ass I I .

When Imax i s declared by the manufacturer an add i tional 8/20 curren t impu lse wi th a crest va lue of Imax sha l l be appl i ed and the res idual vol tage shal l be measured and recorded .

One sequence of pos i ti ve polari ty and one sequence of negative polari ty are appl ied to the SPD.

The i n terval between i nd ividual impu lses shal l be l ong enough for the sample to cool down to ambien t temperature.

IEC

UC

D

DUT

(SPD)

Surge


I EC 61 643-331 : 201 7 © I EC 201 7 – 29 –

The residual vol tage used for determ in ing the measured l im i ting vol tage is the h ighest vol tage value correspond ing to the curren ts for:

• C l ass I : at Iimp

• Cl ass I I : a t In

NOTE The res idual vol tage i s the h i ghest crest va l ue measured du ri ng surge cu rrent fl ow. Any h i gh frequency d i sturbances and spikes before and d uri ng cu rrent fl ow caused by speci fi c generator design , l i ke crowbar generators , are d i sregarded .

The va lue for determ in ing Umax i s the h ighest res idual vol tage measured at In , Imax or Iimp , as

appl icable depend ing on the SPD test cl ass.


– 30 – I EC 61 643-331 : 201 7 © I EC 201 7

MEASURED LIMITING VOLTAGE IN IEC 61 643-1 1 : 201 1

Determine

the measured

l imiting voltage

Test to measure

the residual

voltage with

8/20 current

impulse

(8.3.3.1 )

Test to measure

the l imiting

voltage with

the combination

wave

(see 8.3.3.3)

Class

I or I I Class I I I

Pass criteria

in 8.3.4.6

Test completed

NA Not applicable

NOTE:

Measured l imiting voltage in IEC 61 643-1 1 is referred as clamping voltage Vc in IEC 61 643-331

Start

What

is the class

test ?

Is

there a switching

componnent?

See 7.1 .1 d1 )

NA for MOVs

Front of wave

sparkover test

(see 8.3.3.2)

No

Check that the measured l imiting

voltage does not exceed the

voltage protection level Up as

declared by the manufacturer

Applicable only on the final SPD

IEC

Figure A.3 – Flow chart of testing to determine the measured l imi ting vol tage

A.4.2.3 Limiting vol tage with the combination wave (8.3.3.3)

To perform th is test a combination wave generator i s used .

The i n terval between the i nd ividual impu lses shal l be long enough for the sample to cool d own to ambient temperature.

I f the SPD on l y contains vol tage- l im i ting componen ts th is test needs to be carried ou t at Uoc

on l y.


I EC 61 643-331 : 201 7 © I EC 201 7 – 31 –

With these generator setti ngs four su rges wi l l be appl i ed to the SPD, two wi th pos i ti ve and two wi th negative polari ty.

The value for determ in ing the measured l im i ti ng vol tage and Umax i s the maximum vol tage

recorded du ring th is test.

NOTE Uoc i s open ci rcu i t vol tage of the combination wave generator, at the poin t of connection of the device

under test.

A.4.3 Class I and I I operating duty tests (8.3 .4.3)

Three groups of fi ve impu lses of 8/20 curren t impu lses wi th pos i ti ve polari ty shal l be appl i ed . The test samples are connected to a power source accord ing to 8 . 3. 4. 2. Each impu lse shal l

be synchron ized to the power frequency. Starti ng from 0 ° the synchron isation ang le shal l be

i ncreased in steps of 30 ° wi th a to lerance of ± 5° for each synchron isation ang le. The tests are

described in F igure A. 4.

Figure A.4 – Operating duty test timing d iagram for test classes I and I I

The SPD shal l be energ ized at Uc. The prospective short-ci rcu i t curren t of the power source

shal l comply wi th 8. 4 . 3 . 2 during the appl ication of groups of impu lses. After the appl ication of each g roup of impu lses and after the i n terruption of the last fo l low current ( i f any) the SPD shal l remain energ ized wi thou t in terruption for at l east 1 m in to check for for stabi l i ty. After the l ast g roup of impu lses and the 1 m in period the SPD e i ther remains appl i ed or i s reappl ied wi th in l ess than 30 s to Uc for another 1 5 m in to check for stabi l i ty. For that purpose, the short-ci rcu i t capabi l i ty of the power source (at Uc) may be reduced to 5 A.

When testing MOVs to cl ass I , 8 /20 curren t impu lses wi th a crest correspond ing to Iimp sha l l

be appl ied .

When testi ng MOVs to cl ass I I , 8/20 curren t impu lses wi th In shal l be appl i ed .

I f an MOV is classi fied for test cl ass I and test class I I th is test may be performed on l y once, bu t wi th the most severe set of parameters of both test cl asses, subject to agreement by the manufacturer.

The i n terval between the impu lses is 50 s to 60 s, the i n terval between the groups is 30 m in to 35 m in .

I t i s not requ i red that the test sample i s energ ized between the groups.

A.4.4 Addi tional duty test for test class I

This test i s carried ou t wi th current impu lses in steps up to Iimp pass ing through the SPD.

The MOV shal l be energ ized at Uc. The prospective short-ci rcu i t current of the power source

shal l be 5 A during the appl ication of impu lses. After the appl ication of each impu lse and after

Surge current impu lses

UC

35 m in 35 m in

Operati ng du ty test

1 5 m in

IEC


– 32 – I EC 61 643-331 : 201 7 © I EC 201 7

i n terruption of each fol l ow curren t ( i f any) the SPD shal l remain energ ized wi thout in terruption for at l east 1 m in to check for stabi l i ty. After that period the SPD e i ther remains appl ied or i s reappl ied wi th in l ess than 30 s to Uc for another 1 5 m in to check for stabi l i ty. For that purpose

the short-ci rcu i t capabi l i ty of the power source shal l a lso be 5 A.

Current impu lses of pos i ti ve polari ty shal l be i n i tiated at the correspond ing pos i ti ve crest va lue of the power frequency vol tage source to the energ ized test sample as fol lows:

one current impu lse at 0 , 1 Iimp ; check thermal s tabi l i ty; cool down to ambient temperature;

one current impu lse at 0 , 25 Iimp ; check thermal stabi l i ty; cool down to ambien t temperature;

one current impu lse at 0 , 5 Iimp ; check thermal s tabi l i ty; cool down to ambient temperature;

one current impu lse at 0 , 75 I imp ; check thermal stabi l i ty; cool down to ambien t temperature;

one current impu lse at 1 , 0 Iimp ; check thermal s tabi l i ty; cool down to ambient temperature.

The tim ing d iagram is described i n F igure A.5.

Figure A.5 – Addi tional duty test timing d iagram for test class I

A.4.5 Class I I I operating duty tests

The SPD is tested wi th th ree groups of impu lses correspond ing to UOC wi th :

• five pos i ti ve impu lses i n i ti ated at crest va lue of posi ti ve hal f cycle (±5°)

• five negative impu lses in i ti ated at crest va lue of negative hal f cycle (±5°)

• five pos i ti ve impu lses i n i ti ated at crest va lue of posi ti ve ha l f cycle (±5°)

The tim ing d iagram is described i n F igure A.6.

Figure A.6 – Operating duty test timing d iagram for test class I I I

Combinati on wave impu lse

UC

30 m in 30 m in IEC

UC

5 A

0, 1

1 5 m in

0,25

0 , 5

0 , 75

1 , 0

UC

5 A UC 5 A

UC

5 A

UC

5 A

1 5 m in 1 5 m in 1 5 m in 1 5 m in

Add i ti onal d u ty test for test cl ass I powered at UC d u ri ng and after each impu lse cu rrent shot

IEC


I EC 61 643-331 : 201 7 © I EC 201 7 – 33 –

A.4.6 Pass cri teria for al l operating du ty tests and for the addi tional duty test for test class I

The pass cri teria A, B , C, D, E , F , G and M accord ing to Table 4 of I EC 61 643-1 1 : 201 1 shal l appl y.

A.4.7 Preferred parameters of impulse d ischarge current Iimp used for Class I add i tional duty tests

The impu lse d ischarge curren t passing through the device under test (MOV) i s defined by the crest va lue Iimp , the charge Q and the speci fic energy W/R . The impu lse curren t shal l show no polari ty reversal and shal l reach Iimp wi th in 50 μ s. The transfer of the charge Q shal l occur wi th in 5 ms and the speci fic energy W/R shal l be d i ssipated wi th in 5 ms.

The impu lse du ration shal l not exceed 5 ms.

1 ) Table A. 2 g i ves values of Q (A−s) and W/R (kJ /Ω) for example va lues of Iimp (kA).

The re lationsh ip between Iimp , Q and W/R i s as fo l l ows:

Q = Iimp x a where a = 5 x 1 0 -4 s

W/R = Iimp2 x b where b = 2 , 5 x 1 0 -4

s

Table A.2 – Prefered parameters for class I test

Iimp

with in 50 μs

(kA)

Q

wi th in 5 ms

(A−s)

W/R

wi th in 5 ms

(kJ /Ω)

25 1 2 , 5 1 56

20 1 0 1 00

1 2 , 5 6 , 25 39

1 0 5 25

5 2 , 5 6 , 25

2 1 1

1 0 , 5 0 , 25

NOTE 1 One of the poss ible test impu lses wh ich meet the above parameters i s the 1 0/350 waveshape proposed i n I EC 62305-1 .

The fo l l owing to lerances shal l appl y:

• Iimp -1 0 %/+1 0 %

• Q -1 0 %/+20 %

• W/R -1 0 %/+45 %

NOTE 2 For fu rther gu idance on th i s subject see I EC 61 643-1 1 : 201 1 (Subclause 8 . 3. 4. 4 –Add i ti onal d u ty test for test cl ass I ) .

A.4.8 Preferred values of impulse d ischarge current In used for Class I and Class I I residual vol tage and operating duty tests

Table A. 3 va lues are for a waveshape of 8/20.


– 34 – I EC 61 643-331 : 201 7 © I EC 201 7

Table A.3 – Preferred values for class I and class I I tests

In

(kA)

1 00

70

60

50

40

30

20

1 0

The to lerances on the curren t waveshape pass ing through the device under tests are as fol l ows:

• crest va lue ± 1 0 %

• fron t t ime ± 1 0 %

• t ime to hal f va lue ± 1 0 %

A smal l overshoot or osci l lation is to lerated provided that the ampl i tude of any osci l l ation i s not more than 5 % of the crest va lue. Any polari ty reversal after the curren t has fa l l en to zero shal l not be more than 30 % of the crest value.

NOTE For fu rther gu i dance on th i s subject see I EC 61 643-1 1 : 201 1 (Subclause 8 . 3. 3. 1 – Residual vo l tage wi th 8/20 cu rren t impu lses and Subclause 8. 3. 4 . 3 Cl ass I and I I operati ng d u ty tests) .

A.4.9 Preferred values of combination waveshape used for C lass I I I tests

Table A. 4 values are for a 1 . 2/50-8/20 combination wave generator. The standard impu lses of a combination waveform generator i s characterized by the ou tpu t vol tage under open -ci rcu i t cond i ti ons and the output curren t under short-ci rcu i t cond i tions. The open ci rcu i t vol tage shal l have a fron t t ime of 1 , 2 μs and a time to hal f va lue of 50 μ s. The short-ci rcu i t current shal l have a front t ime of 8 μ s and a time to hal f va lue of 20 μs.

The maximum va lues for crest open-circu i t vol tage UOC and crest chort-ci rcu i t current Isc are

20 kV and 1 0 kA respectivel y. Above these va lues (20 kV /1 0 kA), class I I tests shal l be performed.


I EC 61 643-331 : 201 7 © I EC 201 7 – 35 –

Table A.4 – Preferred values for class I I I tests

UOC

(kV)

ISC

(kA)

20 1 0

1 0 5

8 4

6 3

5 2 , 5

4 2

3 1 , 5

2 1

1 0 , 5

The tolerances of the open ci rcu i t vo l tage UOC at the poin ts where the device under test

(DUT) wi l l be connected are as fol lows:

• crest va lue ± 5 %

• front t ime ± 30 %

• t ime to hal f va lue ± 20 %

These to lerances are for the generator alone, wi thou t of any MOV or power suppl y ci rcu i t be ing connected , depend ing whether the test has to be performed energ ized or un-energ ized .

NOTE 1 For fu rther gu i dance on th i s subject see I EC 61 643-1 1 : 201 1 (Subclause 8 . 1 . 4 – Combination wave used for cl ass I I I tests , paragraph a)) .

The to lerances of the short-ci rcu i t current ISC a t the poin ts where the device under test (DUT)

wi l l be connected are as fol lows:

• crest va lue ± 1 0 %

• front t ime ± 1 0 %

• time to ha l f va lue ± 1 0 %

These generator tolerances shal l be met wi th or wi thout any power suppl y ci rcu i t bein g connected , depend ing whether the test has to be performed energ ized or un-energ ized .

NOTE 2 For fu rther gu i dance on th i s subject see I EC 61 643-1 1 : 201 1 (Subclause 8 . 1 . 4 – Combination wave used for cl ass I I I tests , paragraph b)) .

Test setup:

The ficti ve or effecti ve impedance Zf of the generator shal l be nom inal l y 2 Ω. By defin i tion , the impedance i s the ratio of the crest va lue of the open-ci rcu i t vo l tage UOC d i vi ded by the crest va lue of the short-ci rcu i t curren t ISC .

The above waveform and to lerance requ irements on l y appl y to the test performed at the va lue of UOC d eclared by the manufacturer, wh ich may requ ire some generator ad justments to ach ieve. For test performed below UOC (0 , 1 ; 0 , 2 ; 0 , 5; 1 , 0 times UOC) , no further generator

ad j ustments are requ i red , and the same setti ngs shal l be used .

NOTE 3 For fu rther gu i dance on th i s subject see I EC 61 643-1 1 : 201 1 (Subclause 8 . 1 . 4 – Combination wave used for cl ass I I I tests , paragraph c)) .


– 36 – I EC 61 643-331 : 201 7 © I EC 201 7

Annex B (informative)

IEC 61 051 Varistors for use in electronic equipment

I EC 61 051 covers varistors for use in e l ectron ic equ ipment and consists of two parts: 61 051 -1 for the generic speci fication and 61 051 -2 i s a sectional speci fication for surge suppress ion varistors.

These parts are set up to address qual i ty i n that they have AQL levels and sample s i zes.

The testi ng covers varistor vol tage, l eakage curren t, pu lse curren t, i n su lation res istance, robustness of term inations, solderabi l i ty, bump, shock, vibration , damp heat, envi ronmental , fi re, endurance at temperature and solvent res istance.


I EC 61 643-331 : 201 7 © I EC 201 7 – 37 –

Annex C (informative)

Accelerated endurance screening test

C.1 Accelerated endurance screening test

The purpose of the test i s to check the MOV for i n i ti a l term fa i lu re .

C.2 Preparation of sample

At l east 1 0 samples from the same production l ot shou ld be used . The nom inal varistor vol tage VN of each sample shou ld be measured and recorded prior to th is test. I n add i tion , VN

variation of the samples shal l be wi th in ± 1 %.

C.3 Test condi tions

The samples to be tested are heated to 1 05 °C ± 5 °C in a chamber. The appl ied DC vol tage shal l be at the m in imum VT of the samples tested .

Refer to the test ci rcu i t d i agram as shown i n F igure C. 1 .

Figure C. 1 – Ci rcu i t of accelerated ageing test

The test period is 1 000 hours un less otherwise speci fied . Times of 1 68 h , 366 h and 1 000 h are recommended as i n tervals of VN measurement. A s i ng le 1 000 hours on l y measurement i s

a lso acceptable.

After 1 000 hours' appl ication , VN i s measured for a l l samples after a period of 1 hour or more at room temperature. For each VN measurement, i f the change ratio of VN exceeds ± 1 0 %

from the in i ti a l va l ue, or the fuse is open , the sample i s assumed as defective. Testing (vol tage appl ication) may be stopped i f defectives are found .

DC curren t sou rce Power capaci ty: 1 kVA or more

IEC


– 38 – I EC 61 643-331 : 201 7 © I EC 201 7

C.4 Pass cri teria

The change rate of the nom inal varistor vol tage does not exceed ± 1 0 % from the i n i ti a l va lue.

I t i s not acceptable for any over-curren t fuse or relay to have operated .


I EC 61 643-331 : 201 7 © I EC 201 7 – 39 –

Annex D (informative)

Proposed test method for determination of mean time

to fai lure (MTTF)

D.1 Sampl ing plans

Four sampl i ng p lans are shown in Table D . 1 , wh ich are based on the confidence l evels of 60 % and 90 % , and the perm i tted number of fa i l u res , C, of zero and one. Users can select wh ich of the four p lans to use.

Table D. 1 – Sampl ing plans

Li fe time i n years 5 1 0 1 5 20 30

Li fe time in kh 44 88 1 32 1 76 264

MTTF （ fai l ure number /1 06h ） 22. 7 1 1 . 4 7 . 57 5. 7 3 . 8

Fai lure rate (%/1 000) l evel symbol L-2. 27 L-1 . 1 4 M-0. 76 M-0. 57 M-0. 38

Confidence Level (%)

Permi tted Number of fai lu res C

Cumulative un i t-hours (× 1 06) of M -level *

Cumulative un i t-hours (× 1 06 ) of the test

60 0 0 . 091 6 0 . 0404 0 . 0804 0 . 1 205 0 . 1 607 0 . 241 1

60 1 0 . 202 0 . 089 0 . 1 772 0 . 2658 0 . 3544 0 . 531 6

90 0 0 . 230 0 . 1 01 3 0 . 201 8 0 . 3026 0 . 4035 0 . 6053

90 1 0 . 389 0 . 1 71 4 0 . 341 2 0 . 51 1 8 0 . 6825 1 . 0237

* The cumu lati ve u n i t-hou rs (× 1 06) of M-l evel are benchmarks for cal cu l ati ng the cumu lati ve un i t-hou rs (× 1 06) of the test and are for i n formation on l y.

D.2 Total test hours

I t i s a common practice to carry ou t the MTTF test for 2 000 h i n tota l .

D.3 Samples

The tota l number of samples to be tested may be e i ther NA or (NB1 + NB2) accord ing to the requ ired l i fe time i n years or l i fe time i n kh l i s ted i n Table D. 1 .

NA = [cumu lati ve un i t-hours (× 1 06) of the test se lected from Table D. 1 ] /2000 (D. 1 )

NB1 = NA/3 , NB2 = (2/3)NA/AF (D. 2)

where the sample NA and NB1 are tested under normal rated s tresses of the vol tage and the temperature (VM and maximum operati ng temperature), the sample NB2 are tested under the accelarated stresses of wh ich the acceleration factor i s AF.

The i n i ti a l varistor vol tages of a l l of the samples to be tested shal l d i ffer by not more than 1 % from each other.

NOTE The determ ination of AF i s under consideration .


– 40 – I EC 61 643-331 : 201 7 © I EC 201 7

Test set up

The vol tage source shal l appl y a speci fied test vol tage (± 0 . 5 %) on a l l of the samples The curren t rating of the vol tage source shal l not l im i t the i ncreasing of the sample current.

The temperature of test chambers shal l be the speci fi ed va lue (± 1 K) .

One current sens ing res istor Ry i s connected i n series wi th each sample. The Ry i s p laced ou ts ide of the chamber (see F igure D . 1 a) .The va lue of the Ry i s so se lected that the vol tage across i t i s no more than 0 . 5 % of the test vo l tage. F i gure D. 1 b i s an a l ternative test ci rcu i t wh ich is su i table for l ow vol tage MOVs, i n th is ci rcu i t the l eakage curren t i s converted to vol tage by operational ampl i fi er A and res istor Ry. The accuracy of vol tmeters V1 and V2, and res istor Ry shal l be 1 % .

a) b)

Figure D. 1 – Test C ircu i t of MTTF

NOTE The test ci rcu i t shown i n F i gu re D. 1 b i s based on the Vi rtua l -Zero Pri ncip l e of the operati onal ampl i fi er (OA), wh ich has a very l arge ampl i fi cation factor (greater than 1 0 000 i s common). I f the ou tpu t vol tage of the OA wi th an ampl i fi cati on factor of 1 0 000 changes from 0 mV to 1 000 mV, the i npu t vol tage of the OA (V1 ) changes from 0 mV to 0 . 1 mV that can be regarded as 0 . Therefore, the potenti al of the l ow term inal of the MOV i n F i gu re D. 1 b can be regarded as “zero poten tia l ” or “vi rtual -zero poi n t” . For example, when the cu rrent passing the MOV i s 1 mA and R

y = 1 000 Ω, the outpu t vol tage of OA (V2) i s 1 mA × 1 000 Ω = 1 000 mV, the l ow term inal

potential of the MOV i s 0 , 1 mV.

D.4 Intermediate measurements

The current passing the sample shal l be measured at the test hours of

1 ， 4 ， 24 ， 96 ， 200 ， 500 ， 750 ， 1 000 ， 1 250 ， 1 500 ， 1 750 ， 2 000. I f a steady i ncreas ing

read ing i s observed , a tracking measurement of shorter i n terval sha l l be taken .

D.5 Fai lure cri teria

The current pass ing a sample goes up stead i l y and beyond the speci fied mu l tiple of the i n i ti a l va lue ( the cu rren t value measured at 1 h ) .

D.6 Acceptance cri teria

The numbers of fa i lu re shal l be not more than the values speci fi ed i n Table D. 1 .

IEC IEC


I EC 61 643-331 : 201 7 © I EC 201 7 – 41 –

Bibl iography

I EC 60068-2-6: 2007, Environmental testing – Part 2-6: Tests – Test Fc: Vibration (sinusoidal)

IEC 60068-2-1 4 :2009, Environmental testing – Part 2-14: Tests – Test N: Change of temperature

IEC 60068-2-29: 1 987, Environmental testing – Part 2: Tests – Test Eb and guidance: Bump

I EC 60068-2-52: 1 996, Environmental testing – Part 2: Tests – Test Kb: Salt mist, cyclic (sodium, chloride solution)

IEC TR 62240-1 : 201 3, Process management for avionics – Electronic components capability in operation – Part 1 : Temperature uprating

IEC 60060-1 : 201 0, High-voltage test techniques – Part 1 : General definitions and test requirements

IEC 61 643-1 1 : 201 1 , Low-voltage surge protective devices – Part 11 : Surge protective devices connected to low-voltage power systems – Requirements and test methods

I EC 6061 7, Graphical symbols for diagrams

IEC 61 051 -1 : 2007, Varistors for use in electronic equipment – Part 1 : Generic specification

IEC 61 051 -2: 1 991 , Varistors for use in electronic equipment – Part 2: Sectional specification for surge suppression varistors

___________




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Surge Protective Device SPD Surge Protection Device · Created Date: 12/17/2017 2:13:21 AM