FOREWORD
INTRODUCTION
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols, acronyms and abbreviations
5 Description of quantitative accelerated life tests
5.1 Introduction
5.2 The life distribution
5.3 The life-stress model
6 The Weibull distribution
6.1 Introduction
6.2 Graphical representation
6.3 Calculation of the distribution parameters
6.3.1 Input data to be used
6.3.2 Ranking of the time to failure
6.3.3 Reliability/unreliability estimates
6.3.4 Calculation of the parameters
7 The life-stress model
7.1 General
7.2 Linear equation of the acceleration factor
7.3 Calculation of parameters n and E[a]
8 The quantitative accelerated life testing method
8.1 Selection of samples
8.2 The steps to check product life characteristics
8.3 Procedure for terminating the maximum stress level
test
8.4 Procedure to collect time to failure data and to repair
meters
9 Definition of normal use conditions
9.1 Introduction
9.2 Temperature and humidity conditions
9.2.1 Equipment for outdoor installation
9.2.2 Equipment for indoor installation
9.3 Temperature correction due to variation of
voltage and current
9.3.1 Definition of the normal use profile of voltage
and current
9.3.2 Measurement of the meter internal temperature
at each current and voltage
9.3.3 Calculation of the meter average internal
temperature
9.4 Other conditions
10 Classification and root cause of failures
11 Presentation of the results
11.1 Information to be given
11.2 Example
12 Special cases
12.1 Cases of simplification
12.1.1 Minor evolution of product design
12.1.2 Verification of production batches
12.2 Cases when additional information is needed
12.2.1 The beta parameter changes significantly from
maximum stress level to medium or low stress
level
12.2.2 Fault mode different between stress levels
Annex A (informative) Basic statistical background
Annex B (informative) The characteristics of the Weibull
distribution
Annex C (informative, see also draft IEC 62308) Life-stress
models
Annex D (normative) Rank tables
Annex E (normative) Values of the Gamma function tau(n)
Annex F (normative) Calculation of the minimum duration
of the maximum stress level test
Annex G (informative) Example
Annex ZA (normative) Normative references to international
publications with their corresponding European
publications
Bibliography
INDEX