IEC 61643-331:2017 pdf download

IEC 61643-331:2017 pdf download.Components for low-voltage surge protective devices – Part 331: Performance requirements and test methods for metal oxide varistors (MOV)
1 Scope
This part of IEC 61 643 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.
2 Normative references
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 60068-1 :201 3, Environmental testing – Part 1: General and guidance IEC 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 IEC 60068-2-21 :2006, Environmental testing – Part 2-21: Tests – Test U: Robustness of terminations and integral mounting devices IEC 60068-2-78:201 2, Environmental testing – Part 2-78: Tests – Test Cab: Damp heat, steady state 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 IEC 61 000-4-2:2008, Electromagnetic compatibility (EMC) – Part 4-2: Testing and measurement techniques – Electrostatic discharge immunity test
3 Terms, definitions, symbols and abbreviated terms
For the purposes of this document, the following terms, definitions, symbols and abbreviated terms apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses:3.1 Ratings 3.1.1 absolute maximum ratings limiting values of operating and environmental conditions applicable to a component, device, equipment or machine as defined by its published specification data, which should not be exceeded under the worst possible conditions Note 1 to entry: A limiting condition may be either a maximum or a minimum or both. [SOURCE: MODIFIED: IEC 62240-1 :201 3, Clause 3.1 .1 , modified (“any semiconductor device of a specific type” replaced by “a component, device, equipment or machine”, addition of Note 1 to entry)] 3.1.2 single-impulse [transient] maximum current I TM rated maximum value of current which may be applied for a single impulse of specified waveform Note 1 to entry: For power distribution surge protective devices (SPDs), IEC 61 643-1 1 , Maximum Discharge Current I MAX is used. 3.1.3 nominal discharge current I n crest value of the current through the MOV having a current waveshape of 8/20 3.1 .4 impulse life characteristic graphical representation between impulse current peak (I), equivalent rectangular pulse width (T), and impulse numbers (n) for which the varistor can withstand Note 1 to entry: Unless otherwise specified, the range of T shall be 20 µs to 1 0 ms, the range of n shall be 1 0 6 , 1 0 5 ,1 0 4 , 1 0 3 , 1 0 2 , 1 0 1 and 1 0 0 temperature derating curve. 3.1.5 temperature derating curve graphical representation of parameter derating against temperature Note 1 to entry: Typical parameters are rated voltage, impulse current, energy and average power dissipation. 3.1.6 single-pulse [transient] maximum energy W TM rated maximum value which may be absorbed for a single pulse of a specified waveform Note 1 to entry: Unless otherwise specified, 2 ms rectangular pulse is used (IEC 60060). 3.1.7 maximum continuous voltage V M voltage that may be applied continuously at a specified temperature Note 1 to entry: May also be called U C or maximum continuous operating voltage (MCOV). Note 2 to entry: See Figure 1 .