SIST EN 61810-2:2008
Electromechanical elementary relays -- Part 2: Reliability
Electromechanical elementary relays -- Part 2: Reliability
This part of IEC 61810 covers test conditions and provisions for the evaluation of endurance tests using appropriate statistical methods to obtain reliability characteristics for relays. This standard applies to electromechanical elementary relays considered as non-repaired items (i.e. items which are not repaired after failure), whenever a random sample of items is subjected to a test of cycles to failure (CTF). The lifetime of a relay is usually expressed in number of cycles. Therefore, whenever the terms "time" or "duration" are used in the basic standard IEC 61649, this term is to be understood to mean "cycles". However, with a given frequency of operation, the number of cycles can be transformed into respective times (e.g. TTF, times to failure). The failure criteria and the resulting characteristics of elementary relays describing their reliability in normal use are specified in this standard. A relay failure occurs when the specified failure criteria are met. As the failure rate for elementary relays cannot be considered as constant, particularly due to wear-out mechanisms, the times to failure of tested items typically show a Weibull distribution. This standard provides numerical methods to calculate approximate values for the two-parameter Weibull distribution, as well as lower confidence limits.
Elektromechanische Elementarrelais -- Teil 2: Funktionsfähigkeit (Zuverlässigkeit)
Relais électromécaniques élémentaires -- Partie 2: Fiabilité
Couvre les conditions d'essai et les dispositions pour l'évaluation des essais d'endurance utilisant les méthodes statistiques appropriées pour obtenir les caractéristiques de fiabilité pour relais.
Osnovni elektromehanski releji - 2. del: Zanesljivost (IEC 61810-2:2005)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 61810-2:2008
01-januar-2008
1DGRPHãþD
SIST EN 60255-23:2001
Osnovni elektromehanski releji - 2. del: Zanesljivost (IEC 61810-2:2005)
Electromechanical elementary relays - Part 2: Reliability
Elektromechanische Elementarrelais - Teil 2: Funktionsfähigkeit (Zuverlässigkeit)
Relais électromécaniques élémentaires - Partie 2: Fiabilité
Ta slovenski standard je istoveten z: EN 61810-2:2005
ICS:
29.120.70 Releji Relays
SIST EN 61810-2:2008 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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EUROPEAN STANDARD EN 61810-2
NORME EUROPÉENNE
EUROPÄISCHE NORM May 2005
ICS 29.120.70 Supersedes EN 60255-23:1996
English version
Electromechanical elementary relays
Part 2: Reliability
(IEC 61810-2:2005)
Relais électromécaniques élémentaires Elektromechanische Elementarrelais
Partie 2: Fiabilité Teil 2: Funktionsfähigkeit (Zuverlässigkeit)
(CEI 61810-2:2005) (IEC 61810-2:2005)
This European Standard was approved by CENELEC on 2005-04-01. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and
notified to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,
Switzerland and United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2005 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61810-2:2005 E
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EN 61810-2:2005 - 2 -
Foreword
The text of document 94/214/FDIS, future edition 1 of IEC 61810-2, prepared by IEC TC 94,
All-or-nothing electrical relays, was submitted to the IEC-CENELEC parallel vote and was approved by
CENELEC as EN 61810-2 on 2005-04-01.
This European Standard supersedes EN 60255-23:1996.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2006-01-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2008-04-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61810-2:2005 was approved by CENELEC as a European
Standard without any modification.
__________
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- 3 - EN 61810-2:2005
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following referenced documents are indispensable for the application 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.
NOTE Where an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
IEC 60050-191 1990 International Electrotechnical Vocabulary - -
(IEV)
Chapter 191: Dependability and quality of
service
IEC 60050-444 2002 Part 444: Elementary relays - -
IEC 60300-3-5 2001 Dependability management - -
Part 3-5: Application guide - Reliability
test conditions and statistical test
principles
1)
IEC 61649 - Goodness-of-fit tests, confidence - -
intervals and lower confidence limits for
Weibull distributed data
IEC 61810-1 2003 Electromechanical elementary relays EN 61810-1 2004
Part 1: General and safety requirements
ISO 3534-1 1993 Statistics - Vocabulary and symbols - -
Part 1: Probability and general statistical
terms
1)
Undated reference.
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NORME CEI
INTERNATIONALE IEC
61810-2
INTERNATIONAL
Première édition
STANDARD
First edition
2005-02
Relais électromécaniques élémentaires –
Partie 2:
Fiabilité
Electromechanical elementary relays –
Part 2:
Reliability
IEC 2005 Droits de reproduction réservés Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any
utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including
électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
CODE PRIX
Commission Electrotechnique Internationale PRICE CODE U
International Electrotechnical Commission
Международная Электротехническая Комиссия
Pour prix, voir catalogue en vigueur
For price, see current catalogue
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61810-2 IEC:2005 – 3 –
CONTENTS
FOREWORD.7
INTRODUCTION.11
1 Scope .13
2 Normative references .13
3 Terms and definitions .15
4 General considerations .19
5 Test conditions .21
5.1 Test items .21
5.2 Environmental conditions .21
5.3 Operating conditions.21
5.4 Test equipment.23
6 Failure criteria .23
7 Output data .23
8 Analysis of output data .25
9 Presentation of reliability measures.25
Annex A (normative) Test circuit .29
A.1 Test circuit.29
A.2 Description and requirements.33
A.3 Test schematic .35
A.4 Special loads for telecom and signal relays .35
A.5 Special loads with inrush current.37
Annex B (normative) Data analysis.43
B.1 Introduction .43
B.2 Symbols and definitions .43
B.3 Procedure.43
Annex C (informative) Example .51
C.1 Distribution parameters.51
C.2 Mean cycles to failure (MCTF).51
C.3 Useful life .51
C.4 Mean time to failure (MTTF) .51
Annex D (normative) Contact categories.53
D.1 Contact category 0 (CC 0) – Dry circuit .53
D.2 Contact category 1 (CC 1) – Low load without arcing .53
D.3 Contact category 2 (CC 2) – High load with arcing .53
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61810-2 IEC:2005 – 5 –
Figure A.1 – Standard test circuit .29
Figure A.2 – Functional block diagram.31
Figure A.3 – Circuit for cable load .35
Figure A.4 – Test circuit for inrush current loads (e.g. capacitive loads and simulated
tungsten filament lamp loads) a.c. circuits.37
Figure A.5 – Example for a tungsten filament lamp test for relays rated 10/100 A/250
V~/2,5 ms.39
Figure A.6 – Test circuit for inrush current loads (e.g. capacitive loads and simulated
lamp loads) – d.c. circuits .39
Figure A.7 – Test circuit for inrush current loads (e.g. simulated fluorescent lamp
loads) with power-factor correction.41
Figure D.1 – Contact categories .53
Table 1 – Reliability measures .25
Table A.1 – Characteristics of power sources for contact loads .31
Table A.2 – Standard contact load characteristics.33
Table B.1 – Values of the gamma function.47
Table B.2 – Fractiles of the normal distribution .49
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61810-2 IEC:2005 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROMECHANICAL ELEMENTARY RELAYS −
Part 2: Reliability
FOREWORD
1) 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.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61810-2 has been prepared by IEC technical committee 94: All-or-
nothing electrical relays.
This standard cancels and replaces IEC 60255-23 published in 1994 and adopts all relevant
contents of IEC 60255-14 and IEC 60255-15, both published in 1981 and withdrawn in early
2005.
The text of this standard is based on the following documents:
FDIS Report on voting
94/214/FDIS 94/215/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
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61810-2 IEC:2005 – 9 –
IEC 61810 consists of the following parts, under the general title Electromechanical
elementary relays
Part 1: General and safety requirements
Part 2: Reliability
Part 7: Test and measurement procedures
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
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61810-2 IEC:2005 – 11 –
INTRODUCTION
The superseded standard dealing with the lifetime and reliability characteristics of relays was
IEC 60255-23. The basic content of that standard had been adopted from its predecessor
IEC 60255-0-20. Therefore, the basic concepts of the standard reflected the “state of the art”
of the 1970s.
Following the setting-up of a separate technical committee for all-or-nothing relays (TC 94),
the IEC 61810 series, a new series of basic relay standards covering electromechanical
elementary (non-specified time all-or-nothing) relays, was established.
Within this series, IEC 61810-2 is intended to give requirements and tests permitting the
assessment of relay reliability. Whereas all information concerning endurance tests for type
testing have been included in IEC 61810-1, all relevant contents of IEC 60255-23, as well as
IEC 60255-14 and IEC 60255-15 have been taken into account in IEC 61810-2.
However, in the past decades, the technical committee responsible for dependability (TC 56)
has considerably improved and extended its basic standards. In particular, IEC 60300-3-5
(application guide for determining reliability test conditions and statistical test principles) and
IEC 61649 (which deals with Weibull distributed test data ) are now available.
On the basis of these two publications, IEC 61810-2 was developed. It comprises test
conditions and an evaluation method to obtain relevant reliability measures for
electromechanical elementary relays. The life of relays as non-repairable items is primarily
determined by the number of operations. For this reason the reliability is expressed in terms
of MCTF (mean cycles to failure).
Commonly, equipment reliability is calculated from MTTF (mean time to failure) figures. With
the knowledge of the frequency of operation (cycling rate) of the relay within an equipment it
is possible to calculate an effective MTTF value for the relay in that application.
Such calculated MTTF values for relays can be used to calculate respective reliability,
probability of failure, and availability (e.g. MTBF (mean time between failure)) values for
equipment into which these relays are incorporated.
The MCTF figures can also be used as a basis to make comparative evaluations between
relays with different styles of design or construction, and as an indication of product reliability
under specific conditions.
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61810-2 IEC:2005 – 13 –
ELECTROMECHANICAL ELEMENTARY RELAYS –
Part 2: Reliability
1 Scope
This part of IEC 61810 covers test conditions and provisions for the evaluation of endurance
tests using appropriate statistical methods to obtain reliability characteristics for relays.
This standard applies to electromechanical elementary relays considered as non-repaired
items (i.e. items which are not repaired after failure), whenever a random sample of items is
subjected to a test of cycles to failure (CTF).
The lifetime of a relay is usually expressed in number of cycles. Therefore, whenever the
terms “time” or “duration” are used in the basic standard IEC 61649, this term is to be
understood to mean “cycles”. However, with a given frequency of operation, the number of
cycles can be transformed into respective times (e.g. TTF, times to failure).
The failure criteria and the resulting characteristics of elementary relays describing their
reliability in normal use are specified in this standard. A relay failure occurs when the
specified failure criteria are met.
As the failure rate for elementary relays cannot be considered as constant, particularly due to
wear-out mechanisms, the times to failure of tested items typically show a Weibull
distribution. This standard provides numerical methods to calculate approximate values for
the two-parameter Weibull distribution, as well as lower confidence limits.
2 Normative references
The following referenced documents are indispensable for the application 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 60050-191:1990, International Electrotechnical Vocabulary (IEV) – Chapter 191:
Dependability and quality of service
IEC 60050-444:2002, International Electrotechnical Vocabulary (IEV) – Part 444: Elementary
relays
IEC 60300-3-5:2001, Dependability management – Part 3-5: Application guide – Reliability
test conditions and statistical test principles
IEC 61649:1997, Goodness-of-fit tests, confidence intervals and lower confidence limits for
Weibull distributed data
IEC 61810-1:2003, Electromechanical elementary relays – Part 1: General and safety
requirements
ISO 3534-1:1993, Statistics – Vocabulary and symbols – Part 1: Probability and general
statistical terms
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61810-2 IEC:2005 – 15 –
3 Terms and definitions
For the purposes of this document, the terms and definitions of IEC 60050-191 and
IEC 60050-444 , some of which are reproduced below, as well as the following, apply.
3.1
item
any component that can be individually considered
[IEV 191-01-01, modified]
NOTE For the purpose of this standard, items are elementary relays.
3.2
non-repaired item
item which is not repaired after a failure
[IEV 191-01-03, modified]
3.3
cycle
operation and subsequent release/reset
[IEV 444-02-11]
3.4
frequency of operation
number of cycles per unit of time
[IEV 444-02-12]
3.5
reliability
ability of an item to perform a required function under given conditions for a given number of
cycles or time interval
[IEV 191-02-06, modified]
NOTE 1 It is generally assumed that the item is in a state to perform this required function at the beginning of the
time interval.
NOTE 2 The term “reliability” is also used as a measure of reliability performance (see IEV 191-12-01).
3.6
reliability test
experiment carried out in order to measure, quantify or classify a reliability measure or
property of an item
[3.1.27 of IEC 60300-3-5]
3.7
life test
test with the purpose of estimating, verifying or comparing the lifetime of the class of items
being tested
[3.1.17 of IEC 60300-3-5]
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61810-2 IEC:2005 – 17 –
3.8
cycles to failure
CTF
total number of cycles of an item, from the instant it is first put in an operating state until
failure
3.9
mean cycles to failure
MCTF
expectation of the number of cycles to failure
3.10
time to failure
TTF
total time duration of operating time of an item, from the instant it is first put in an operating
state until failure
[IEV 191-10-02, modified]
3.11
mean time to failure
MTTF
expectation of the time to failure
[IEV 191-12-07]
3.12
useful life
number of cycles or time duration until a certain percentage of items have failed
NOTE In this standard, this percentage is defined as 10 %.
3.13
failure
termination of the ability of an item to perform a required function
[IEV 191-04-01, modified]
3.14
malfunction
single event when an item does not perform a required function
3.15
contact failure
occurrence of break and/or make malfunctions of a contact under test, exceeding a specified
number
3.16
failure criteria
set of rules used to decide whether an observed event constitutes a failure
[3.1.10 of IEC 60300-3-5]
3.17
contact category
classification of relay contacts dependent on wear-out mechanisms
NOTE Various contact categories are defined in Annex D.
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61810-2 IEC:2005 – 19 –
4 General considerations
The provisions of this part of IEC 61810 are based on the relevant publications on
dependability. In particular, the following documents have been taken into account:
IEC 60050-191, IEC 60300-3-5 and IEC 61649.
The aim of reliability testing as given in this standard is to obtain objective and reproducible
data on reliability performance of elementary relays representative of standard production
quality. The tests described and the related statistical tools to gain reliability measures based
on the test results can be used for the estimation of such reliability measures, as well as for
the verification of stated measures.
According to Clauses 8 and 9 of IEC 60300-3-5, for non-repaired items showing a non-
constant failure rate the Weibull model is the most appropriate statistical tool for evaluation of
reliability measures. This analysis procedure is described in IEC 61649.
Elementary relays within the scope of this standard are considered as non-repaired items.
They generally do not exhibit a constant failure rate but a failure rate increasing with time,
being tested until wear-out mechanisms become predominant. The cycles to failure of a
random sample of tested items typically show the Weibull distribution.
The statistical procedures of this standard are valid only when at least 10 relevant failures are
recorded.
The first step in the analysis of the recorded cycles to failure (CTF) of the tested relays is the
determination of the two distribution parameters of the Weibull distribution. In a second step,
the mean cycles to failure (MCTF) is calculated as a point estimate. In a third step, the useful
life is determined as the lower confidence limit of the number of cycles by which 10 % of the
relay population will have failed (B ).
10
With a given frequency of operation these reliability measures expressed in number of cycles
(MCTF) can be transformed into respective times (MTTF), see Annex C for an example.
The statistical procedures require some appropriate computing facility. Software for
evaluation of Weibull distributed data is commercially available on the market. Such software
may be used for the purpose of this standard provided it shows equivalent results when the
data given in Annex C are used.
Since the number of cycles to failure highly depends on the specific set of test conditions
(particularly the electrical loading of the relay contacts), values for MCTF and useful life
derived from test data apply only to this set of test conditions, which have to be stated by the
manufacturer together with the reliability measures.
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61810-2 IEC:2005 – 21 –
5 Test conditions
5.1 Test items
As a minimum of 10 failures need to be recorded to perform the analysis described in this
standard, 10 or more items (relays) should be submitted to the test. This allows the test to be
truncated when at least 10 relays have failed.
The items shall be selected at random from the same production lot and shall be of identical
type and construction. No action is allowed on the test items from the time of sampling until
the test starts.
Where any particular burn-in procedure or reliability stress screening is employed by the
manufacturer prior to sampling, this shall apply to all production. The manufacturer shall
describe and declare such procedures, together with the test results.
Unless otherwise specified by the manufacturer, all contacts of each relay under test shall be
loaded as stated and monitored continuously during the test.
The test starts with all items and is stopped after a certain number of cycles. At that instant a
certain number of items (minimum: 10 items) have failed. The number of cycles to failure of
each of the failed items is recorded.
Items failed during the test are not replaced once they fail.
5.2 Environmental conditions
The testing environment shall be the same for all items.
– The items shall be mounted in the manner intended for normal service; in particular, relays
for mounting onto printed circuit-boards are tested in the horizontal position, unless
otherwise specified.
– The ambient temperature shall be as specified by the manufacturer.
– All other influence quantities shall comply with the values and tolerance ranges given in
Table 1 of IEC 61810-1, unless otherwise specified.
5.3 Operating conditions
The set of operating conditions
– rated coil voltage(s),
– coil suppression (if any),
– frequency of operation,
– duty factor,
– contact load(s),
– contact category according to Annex D
shall be as specified by the manufacturer.
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61810-2 IEC:2005 – 23 –
Recommended values should be chosen from those given in Clause 5 of IEC 61810-1.
The test is performed on each contact load and each contact material as specified by the
manufacturer.
All specified devices (for example, protective or suppression circuits), if any, which are part of
the relay or stated by the manufacturer as necessary for particular contact loads, should be
operated d
...
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