BS EN IEC 61643-331:2018 – TC:2020 Edition
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Tracked Changes. Components for low-voltage surge protective devices – Performance requirements and test methods for metal oxide varistors (MOV)
| Published By | Publication Date | Number of Pages |
| BSI | 2020 | 106 |
IEC 61643-331:2017 is a test specification for metal oxide varistors (MOV), which are used for applications up to 1 000 V AC or 1 500 V DC in power line, or telecommunication, or signalling circuits. They are designed to protect apparatus or personnel, or both, from high transient voltages. This specification applies to MOVs having two electrodes and hybrid overvoltage protection components. This specification also does not apply to mountings and their effect on the MOV’s characteristics. Characteristics given apply solely to the MOV mounted only in the ways described for the tests. This second edition cancels and replaces the first edition published in 2003. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) Update of the nominal varistor voltage test method; b) Addition of thermally protected varistors – component symbol and test methods; c) Addition of nominal discharge current – test methods; d) Addition of voltage ratings for disc types (Table 1); e) Addition of test currents for clamping voltage of disc types (Table 2); f) Addition of typical voltage ratings of SMD types (Table 3); and g) Addition of Limited current and temporary overvoltage tests for thermally protected varistors. Keywords: metal oxide varistors (MOV), high transient voltages.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 60 | undefined |
| 66 | CONTENTS |
| 69 | FOREWORD |
| 71 | 1 Scope 2 Normative references 3 Terms, definitions, symbols and abbreviated terms |
| 72 | 3.1 Ratings |
| 73 | 3.2 Characteristics |
| 74 | 3.3 Symbols Figures Figure 1 – V-I characteristic of an MOV Figure 2 – Symbol for MOV |
| 75 | 3.4 Abbreviated terms 4 Service conditions 4.1 Operating and storage temperature ranges 4.2 Altitude or atmospheric pressure range 4.3 Relative Humidity Figure 3 – Symbol for thermally protected MOV |
| 76 | 5 Mechanical requirements and materials 5.1 Robustness of terminations 5.2 Solderability 5.3 Marking 6 General 6.1 Failure rates 6.2 Test standard atmospheric conditions 7 Electrical requirements 7.1 Nominal varistor voltage |
| 77 | 7.2 Maximum AC (DC) continuous operating voltage 7.3 Standby current IDC 7.4 Capacitance 7.5 Clamping voltage Tables Table 1 – Typical voltage ratings for disc types |
| 78 | Table 2 – Typical voltage ratings for SMD types |
| 79 | 7.6 Electrostatic discharge (ESD) (for SMD type MOV only) 7.7 Rated impulse energy (WTM) 7.8 Nominal discharge current In 7.9 Endurance 7.10 Limited current temporary overvoltage 8 Standard design test criteria 8.1 General 8.2 Ratings 8.2.1 Single-impulse maximum current (ITM) |
| 80 | 8.2.2 Next Impulse 8.2.3 Continuous rated voltage (VM) 8.3 Electrical characteristics 8.3.1 Clamping voltage (VC) Figure 4 – Test circuit for single-impulse maximum current |
| 81 | 8.3.2 Standby current (ID) 8.3.3 Nominal varistor voltage (VN) 8.3.4 Capacitance (CV) Figure 5 – Test circuit for measuring leakage current Figure 6 – Test circuit for measuring nominal varistor voltage (VN) |
| 82 | 8.4 Endurance 8.5 ESD Test Method 9 Nominal discharge current and limited current temporary overvoltage 9.1 Thermally protected varistors – Sequence of tests 9.2 Temperature and humidity cycle conditioning |
| 83 | 9.3 Nominal discharge current I(n) test description 9.3.1 General |
| 84 | Figure 7 – Nominal Discharge Current Flowchart |
| 85 | 9.3.2 Pass/fail criteria 9.4 Limited current temporary overvoltage test description and procedure for thermally protected varistors 9.4.1 General 9.4.2 Sample preparation 9.4.3 Test conditions Figure 8 – Sequence of the In Test |
| 86 | 9.4.4 Pass/fail criteria |
| 87 | Figure 9 – Temporary Overvoltage Limited Current test procedure Flowchart |
| 88 | 9.5 Dielectric testing 9.5.1 Test conditions 9.5.2 Setup from foil to leads 9.5.3 Pass criteria |
| 89 | Annex A (informative) MOV testing according to IEC 61643-11:2011 – Surge protective devices for the Class I, II and III A.1 General A.2 MOV selection A.3 Cross reference list of abbreviations, descriptions and definitions |
| 90 | A.4 Operating duty test A.4.1 General Table A.1 – Comparison of IEC 61643-11 and IEC 61643-311 |
| 91 | Figure A.1 – Flow chart of the operating duty test |
| 92 | A.4.2 Measured limiting voltage Figure A.2 – Test set-up for operating duty test |
| 94 | Figure A.3 – Flow chart of testing to determine the measured limiting voltage |
| 95 | A.4.3 Class I and II operating duty tests (8.3.4.3) A.4.4 Additional duty test for test class I Figure A.4 – Operating duty test timing diagram for test classes I and II |
| 96 | A.4.5 Class III operating duty tests Figure A.5 – Additional duty test timing diagram for test class I Figure A.6 – Operating duty test timing diagram for test class III |
| 97 | A.4.6 Pass criteria for all operating duty tests and for the additional duty test for test class I A.4.7 Preferred parameters of impulse discharge current Iimp used for Class I additional duty tests A.4.8 Preferred values of impulse discharge current In used for Class I and Class II residual voltage and operating duty tests Table A.2 – Prefered parameters for class I test |
| 98 | A.4.9 Preferred values of combination waveshape used for Class III tests Table A.3 – Preferred values for class I and class II tests |
| 99 | Table A.4 – Preferred values for class III tests |
| 100 | Annex B (informative) IEC 61051 Varistors for use in electronic equipment |
| 101 | Annex C (informative) Accelerated endurance screening test C.1 Accelerated endurance screening test C.2 Preparation of sample C.3 Test conditions Figure C.1 – Circuit of accelerated ageing test |
| 102 | C.4 Pass criteria |
| 103 | Annex D (informative) Proposed test method for determination of mean time to failure (MTTF) D.1 Sampling plans D.2 Total test hours D.3 Samples Table D.1 – Sampling plans |
| 104 | D.4 Intermediate measurements D.5 Failure criteria D.6 Acceptance criteria Figure D.1 – Test Circuit of MTTF |
| 105 | Bibliography |
