IEC 60605-6:2007
(Main)Equipment reliability testing - Part 6: Tests for the validity and estimation of the constant failure rate and constant failure intensity
Equipment reliability testing - Part 6: Tests for the validity and estimation of the constant failure rate and constant failure intensity
Specifies procedures to verify the assumption of a constant failure rate or constant failure intensity as defined in IEC 60050(191). These procedures are applicable whenever it is necessary to verify these assumptions. This may be due to a requirement or for the purpose of assessing the behaviour in time of the failure rate or the failure intensity. The major technical changes with respect to the previous edition concern the inclusion of corrected formulae for tests previously included in a corrigendum, and the addition of new methods for the analysis of multiple items.
Essais de fiabilité des équipements - Partie 6: Tests pour la validité et l'estimation du taux de défaillance constant et de l'intensité de défaillance constante
Spécifie les procédures pour vérifier la validité des hypothèses du taux de défaillance constant ou de l'intensité de défaillance constante, ces termes étant compris selon leur définition donnée dans la CEI 60050(191). Ces procédures sont applicables chaque fois que nécessaire pour vérifier ces hypothèses. Cette nécessité peut être due à une exigence ou dans l'intention d'évaluer le comportement en fonction du temps du taux de défaillance ou de l'intensité de défaillance. Les principaux changements par rapport à l'édition précédente concernent l'introduction des formules corrigées des tests précédemment inclus dans un corrigendum et l'ajout de nouvelles méthodes pour l'analyse de divers éléments.
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Standards Content (Sample)
INTERNATIONAL IEC
STANDARD
CEI
60605-6
NORME
Third edition
INTERNATIONALE
Troisième édition
2007-05
Equipment reliability testing –
Part 6:
Tests for the validity and estimation
of the constant failure rate
and constant failure intensity
Essais de fiabilité des équipements –
Partie 6:
Tests pour la validité et l’estimation du taux
de défaillance constant et de l’intensité
de défaillance constante
Reference number
Numéro de référence
IEC/CEI 60605-6:2007
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INTERNATIONAL IEC
STANDARD
CEI
60605-6
NORME
Third edition
INTERNATIONALE
Troisième édition
2007-05
Equipment reliability testing –
Part 6:
Tests for the validity and estimation
of the constant failure rate
and constant failure intensity
Essais de fiabilité des équipements –
Partie 6:
Tests pour la validité et l’estimation du taux
de défaillance constant et de l’intensité
de défaillance constante
PRICE CODE
X
CODE PRIX
Commission Electrotechnique Internationale
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue
Pour prix, voir catalogue en vigueur
– 2 – 60605-6 © IEC:2007
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Normative references.7
3 Terms and definitions .7
4 Symbols .8
5 Requirements .9
6 Test for constant failure rate .9
6.1 General remark concerning Clause 6 .9
6.2 Statistical test for constant failure rate .10
6.3 Probability plot.12
6.4 Total time on test plot .12
6.5 Hazard plot.13
6.6 Action to be taken if constant failure rate assumption is rejected .14
7 Test for constant failure intensity .15
7.1 General remark concerning Clause 7 .15
7.2 Test for constant failure intensity for a single repaired item .15
7.3 Test for constant failure intensity for multiple repaired items .16
7.4 M t plot .18
()
7.5 Action to be taken if the constant failure intensity assumption is rejected.19
Annex A (informative) Examples of the procedures given in this standard .20
Annex B (informative) Example of M(t) analysis for field data.34
Annex C (informative) Preparation of field data for M(t) analysis .39
Bibliography .43
Figure 1 – Tests for constant failure rate – Chart showing structure of Clause 6.10
Figure 2 – Tests for constant failure intensity – Chart showing structure of Clause 7 .15
Figure A.1 – Probability plot to check constancy of failure rate.26
Figure A.2 – Hazard plot to examine constancy of failure rate .28
Figure A.3 – M(t) plot for three repaired items .30
Figure A.4 – M(t) plot with 95 % confidence intervals .31
Figure A.5 – TTT plot to examine constancy of failure rate.33
Figure B.1 – Population of systems in use as function of operational time .35
Figure B.2 – Repair per month as percentage of population in use.36
Figure B.3 – M(t) plot .37
Figure B.4 – M(t) curve with 99 % confidence limits .38
Figure B.5 – Number of repairs per phone .38
60605-6 © IEC:2007 – 3 –
Table 1 – Critical value U as a function of α.11
α
Table 2 – Computation of times to failure for multiple repaired items.17
Table 3 – Quantiles for standardized normal distribution .19
Table A.1 – Twenty ordered times to failure out of 40 tested items.20
Table A.2 – Accumulated times to failure.20
Table A.3 – Time ordered sequence of failure times .21
Table A.4 – Accumulated times to failure.21
Table A.5 – Eight times at which item failures occurred .22
Table A.6 – Accumulated times to failure.23
Table A.7 – Failure data for multiple copy of repaired item.23
Table A.8 – Worksheet for computations .24
Table A.9 – Times to failure from test of non-repaired item .25
Table A.10 – Worksheet with calculations.25
Table A.11 – Ten ordered times with multiple modes .27
Table A.12 – Worksheet and calculations .28
Table A.13 – Failure times for three identical items of repaired item.29
Table A.14 – Worksheet with computations for M(t) .29
Table A.15 – Worksheet with computations for confidence intervals for M(t) .30
Table A.16 – Confidence intervals for M(t) .31
Table A.17 – Times to failure.32
Table A.18 – Worksheet and calculations .33
– 4 – 60605-6 © IEC:2007
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
EQUIPMENT RELIABILITY TESTING –
Part 6: Tests for the validity and estimation
of the constant failure rate and constant failure intensity
FOREWORD
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