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IEC 61643-331
Edition 3.0 2020-03
INTERNATIONAL
STANDARD
colour
inside
Components for low-voltage surge protection –
Part 331: Performance requirements and test methods for metal oxide varistors
(MOV)
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IEC 61643-331
Edition 3.0 2020-03
INTERNATIONAL
STANDARD
colour
inside
Components for low-voltage surge protection –
Part 331: Performance requirements and test methods for metal oxide varistors
(MOV)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.040.20 ISBN 978-2-8322-7905-2
– 2 – IEC 61643-331:2020 © IEC 2020
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms, definitions, symbols and abbreviated terms . 8
3.1 Terms and definitions . 8
3.1.1 Ratings . 8
3.1.2 Characteristics. 9
3.2 Symbols and abbreviated terms used in this document . 11
3.2.1 Symbols . 11
3.2.2 Abbreviated terms . 11
4 Service conditions . 12
4.1 Operating and storage temperature ranges . 12
4.2 Altitude or atmospheric pressure range . 12
4.3 Relative Humidity . 12
5 Mechanical requirements and materials . 12
5.1 Robustness of terminations . 12
5.2 Solderability . 12
5.3 Marking . 12
6 General . 13
6.1 Failure rates . 13
6.2 Test standard atmospheric conditions . 13
7 Electrical requirements . 13
7.1 Varistor voltage (V ) . 13
V
7.2 Maximum AC (DC) continuous voltage (V / V ) . 13
M(AC) M(DC)
7.3 Standby current (I ) . 13
D
7.4 Capacitance (C ) . 13
V
7.5 Clamping voltage (V ) . 13
C
7.6 Electrostatic discharge (ESD) (for SMD type MOV only). 15
7.7 Rated impulse energy . 15
7.8 Nominal discharge current (I ) . 15
n
7.9 Endurance . 15
7.10 Limited current temporary overvoltage . 15
8 Standard design test criteria . 16
8.1 General . 16
8.2 Ratings . 16
8.2.1 Single-impulse maximum current (I ) . 16
TM
8.2.2 Next impulse . 16
8.2.3 Maximum Continuous voltage (V ) . 17
M
8.3 Electrical Characteristics . 17
8.3.1 Clamping voltage (V ) . 17
C
8.3.2 Standby current (I ) . 17
D
8.3.3 Varistor voltage (V ) . 17
V
8.3.4 Capacitance (C ) . 18
V
8.3.5 Rated energy . 18
8.4 Varistor Rating Assurance Testing . 18
8.5 ESD test . 19
9 Nominal discharge current and limited current temporary overvoltage. 19
9.1 Thermally protected varistors – Sequence of tests . 19
9.2 Temperature and humidity cycle conditioning . 19
9.3 Nominal discharge current (I ) test description . 20
n
9.3.1 General . 20
9.3.2 Pass/fail criteria . 22
9.4 Limited current temporary overvoltage test description and procedure for
thermally protected varistors . 22
9.4.1 General . 22
9.4.2 Sample preparation . 23
9.4.3 Test conditions . 23
9.4.4 Pass/fail criteria . 23
9.5 Dielectric testing . 24
9.5.1 Test conditions for thermally protected MOV . 24
9.5.2 Setup from foil to leads . 25
9.5.3 Pass criteria . 25
9.6 Insulation Resistance . 25
Annex A (informative) MOV testing according to the IEC 61643-11:2011 Surge
protective devices for the Class I, II and III . 26
A.1 General . 26
A.2 MOV selection . 26
A.3 Cross reference list of abbreviations, descriptions and definitions . 26
A.4 Operating duty test . 27
A.4.1 General . 27
A.4.2 Class I and II operating duty tests (8.4.4.3) . 32
A.4.3 Additional duty test for test class I . 33
A.4.4 Class III operating duty tests . 33
A.4.5 Pass criteria for all operating duty tests and for the additional duty test
for test class I . 34
A.4.6 Preferred parameters of impulse discharge current I used for Class I
imp
additional duty tests . 34
A.4.7 Preferred values of impulse discharge current I used for Class I and
n
Class II residual voltage and operating duty tests . 35
A.4.8 Preferred values of combination generator waveshape used for Class III
tests . 35
Annex B (informative) IEC 61051 Varistors for use in electronic equipment . 38
Annex C (normative) Accelerated Endurance screening test . 39
C.1 Accelerated endurance screening test . 39
C.2 Preparation of sample . 39
C.3 Test conditions . 39
C.4 Refer to test circuit diagram as shown in Figure C.1. . 39
C.5 Pass criteria . 40
Annex D (informative) Proposed test method of MTTF – Mean time to failure (MTTF) . 41
D.1 Sampling plans . 41
D.2 Total test hours . 41
D.3 Samples. 41
D.4 Test set-up . 42
D.5 Intermediate measurements . 42
D.6 Failure criteria . 42
– 4 – IEC 61643-331:2020 © IEC 2020
D.7 Acceptance criteria . 42
Figure 1 – V-I characteristic of an MOV .
...