colour inside
Varistors for use in electronic equipment –
Part 2: Sectional specification for surge suppression varistors
IEC 61051-2:2021-11(en-fr)
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Varistors for use in electronic equipment –
Part 2: Sectional specification for surge suppression varistors
INTERNATIONAL ELECTROTECHNICAL COMMISSION
COMMISSION ELECTROTECHNIQUE INTERNATIONALE
ICS 31.040.20 ISBN 978-2-8322-1045-7
® Registered trademark of the International Electrotechnical Commission Marque déposée de la Commission Electrotechnique Internationale
CONTENTS
Terms and definitions 7
Preferred characteristics 7
Climatic categories 7
Voltage ratings 7
Derating for metal oxide varistors 9
General 9
Derating at increased operating temperatures 9
Maximum peak current derating characteristic 10
Test procedures, test severities and performance requirements 11
General 11
Visual examination and check of dimensions 11
Electrical tests 11
Varistor voltage 11
Leakage current 11
Capacitance 11
Voltage proof 11
Clamping voltage 11
Maximum peak current 11
Rated energy 11
Soldering test 12
Resistance to soldering heat 12
Solderability 12
Temperature and climate test 12
Damp heat, steady state 12
Endurance at upper category temperature 12
Rapid change of temperature 12
Climatic sequence 12
Robustness test 12
Robustness of terminations 12
Shock testing 12
Vibration 13
Solvent resistance of marking 13
Fire hazard (Needle flame test) 13
Marking, packaging and ordering information 13
Detail specifications 13
General 13
Outline drawing and dimensions 13
Mounting 14
Ratings and characteristics 14
Marking 14
Ordering information 14
Quality assessment procedure 14
General 14
Primary stage of manufacturer 14
Structurally similar components 14
Qualification approval (QA) 15
Qualification approval (QA) procedures 15
Fixed sample size procedure 15
Test schedule 15
Quality conformance inspection 19
General 19
Formation of inspection lots 19
Test schedule 19
Assessment level 19
Annex X (informative) Cross-references to the previous edition of this document 21
Figure 1 – Typical temperature derating curve for maximum continuous voltage, surge
current, energy absorption and average power dissipation 10
Figure 2 – Typical maximum peak current derating curve 10
Table 1 – Upper and lower category temperature and duration of the damp heat,
steady state test 7
Table 2 – Preferred voltage ratings for disk type varistors 8
Table 3 – Preferred voltage ratings for SMD types 9
Table 4 – Test schedule for the qualification approval 16
Table 5 – Test schedule for the qualification approval 20
Table 6 – Periodic inspection 20
Table X.1 – Cross-references 21
INTERNATIONAL ELECTROTECHNICAL COMMISSION
The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
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IEC 61051-2 has been prepared by IEC technical committee 40: Capacitors and resistors for electronic equipment. It is an International Standard.
This second edition cancels and replaces the first edition published in 1991 and Amendment 1:2009. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
revision for the structure in accordance with ISO/IEC Directives, Part 2) to the extent practicable, and for harmonizing with IEC 61051-1:2018;
Annex X has been added for comparison with the previous edition;
two lists of preferred voltage ratings for disk type and SMD type varistors have been added;
permissible numbers of non-conforming items have been set to zero (zero fault) in the test schedule in 8.4.3.
The text of this International Standard is based on the following documents:
Draft | Report on voting |
40/2877/FDIS | 40/2895/RVD |
Full information on the voting for its approval can be found in the report on voting indicated in the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are described in greater detail at www.iec.ch/standardsdev/publications.
A list of all parts in the IEC 61051 series, published under the general title Varistors for use in electronic equipment, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the stability date indicated on the IEC website under webstore.iec.ch in the data related to the specific document. At this date, the document will be
reconfirmed,
withdrawn,
replaced by a revised edition, or
amended.
This part of IEC 61051 is a sectional specification and is applicable to metal oxide varistors with symmetrical voltage-current characteristics for use in electronic equipment connected to any AC or DC supply system.
These varistors are designed to protect electronic and other sensitive equipment from high transient surges. Varistors under the scope of this sectional specification are not intended to give primary protection against lightning surges.
These varistors have metallic connections and are intended to be mounted as through hole component or directly on to printed boards.
The object of this document is to prescribe preferred ratings and characteristics and to select from IEC 61051-1 the appropriate quality assessment procedures, tests and measuring methods, and to give general performance requirements for this type of varistors.
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 60062, Marking codes for resistors and capacitors
IEC 60068-1, Environmental testing – Part 1: General and guidance
IEC 60068-2-1, Environmental testing – Part 2-1: Tests – Test A: Cold
IEC 60068-2-2, Environmental testing – Part 2-2: Tests – Test B: Dry heat
IEC 60068-2-6, Environmental testing – Part 2-6: Tests – Test Fc: Vibration (sinusoidal)
IEC 60068-2-20, Environmental testing – Part 2-20: Tests – Test Ta and Tb: Test methods for solderability and resistance to soldering heat of devices with leads
IEC 60068-2-27, Environmental testing – Part 2-27: Tests – Test Ea and guidance: Shock
IEC 60068-2-30, Environmental testing – Part 2-30: Tests – Test Db: Damp heat, cyclic (12 h + 12 h cycle)
IEC 60068‑2‑45, Basic environmental testing procedures – Part 2-45: Tests – Test XA and guidance: Immersion in cleaning solvents
IEC 60695-11-5, Fire hazard testing – Part 11-5: Test flames – Needle-flame test method – Apparatus, confirmatory test arrangement and guidance