IEC 61810-2:2011

IEC 61810-2 ®
Edition 2.0 2011-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electromechanical elementary relays –
Part 2: Reliability
Relais électromécaniques élémentaires –
Partie 2: Fiabilité
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IEC 61810-2 ®
Edition 2.0 2011-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electromechanical elementary relays –
Part 2: Reliability
Relais électromécaniques élémentaires –
Partie 2: Fiabilité
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX V
ICS 29.120.70 ISBN 978-2-88912-376-6

– 2 – 61810-2 © IEC:2011
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 General considerations . 9
5 Test conditions . 10
5.1 Test items . 10
5.2 Environmental conditions . 10
5.3 Operating conditions . 10
5.4 Test equipment . 11
6 Failure criteria . 11
7 Output data . 11
8 Analysis of output data . 11
9 Presentation of reliability measures . 12
Annex A (normative) Data analysis . 13
Annex B (informative) Example of numerical and graphical Weibull analysis . 22
Annex C (informative) Example of cumulative hazard plot . 26
Annex D (informative) Gamma function . 32
Bibliography . 33

Figure A.1 – An example of Weibull probability paper . 16
Figure A.2 – An example of cumulative hazard plotting paper . 18
Figure A.3 – Plotting of data points and drawing of a straight line . 18
Figure A.4 – Estimation of distribution parameters . 19
Figure B.1 – Weibull probability chart for the example. 24
Figure C.1 – Estimation of distribution parameters . 28
Figure C.2 – Cumulative hazard plots . 30

Table B.1 – Ranked failure data . 23
Table C.1 – Work sheet for cumulative hazard analysis . 26
Table C.2 – Example work sheet . 29
Table D.1 – Values of the gamma function . 32

61810-2 © IEC:2011 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROMECHANICAL ELEMENTARY RELAYS –

Part 2: Reliability
FOREWORD
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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 second edition cancels and replaces the first edition published in 2005. This edition
constitutes a technical revision.
The main changes with respect to the previous editions are listed below:
• inclusion of both numerical and graphical methods for Weibull evaluation;
• establishment of full coherence with the second edition of the basic reliability standard
IEC 61649;
• deletion of previous Annex A and Annex D since both annexes are contained in
IEC 61810-1.
– 4 – 61810-2 © IEC:2011
The text of this standard is based on the following documents:
FDIS Report on voting
94/316/FDIS 94/325/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.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 61810 series can be found, under the general title
Electromechanical elementary relays, on the IEC website.
This International Standard is to be used in conjunction with IEC 61649:2008.
The committee has decided that the contents of this publication will remain unchanged until
the stability 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.
61810-2 © IEC:2011 – 5 –
INTRODUCTION
Within the IEC 61810 series of basic standards covering elementary electromechanical relays,
IEC 61810-2 is intended to give requirements and tests permitting the assessment of relay
reliability. All information concerning endurance tests for type testing have been included in
IEC 61810-1.
NOTE According to IEC 61810-1, a specified value for the electrical endurance under specific conditions (e.g.
contact load) is verified by testing 3 relays. None is allowed to fail. Within this IEC 61810-2, a prediction of the
reliability of a relay is performed using statistical evaluation of the meas
...