BS 142-4.1(1984) : 1984

Foreword
Committees responsible
Specification
Subsection one. General
1 Scope
2 Definitions
Subsection two. Performance
3 Characteristic values
4 Limits of the operative range of the auxiliary
    energizing quantities
5 Operation and accuracy
6 Thermal requirements
7 Rated burden
8 Mechanical classification
9 Construction
10 Contact performance
11 Marking and data
Subsection three. Tests
12 General
13 Tests related to accuracy and operating
    characteristics
14 Tests for performance with through current
15 Insulation tests
16 Thermal tests
17 Mechanical tests
18 High-frequency disturbance test
Appendices
A Recommended methods of presenting relay
    characteristics and performance
B Recommended method of measuring harmonic restraint
    characteristics
Tables
1 Reference conditions and test tolerances of
    influencing quantities and factors
2 Limits of the nominal ranges of influencing
    quantities and factors
Figures
1 Test circuits for checking operating characteristics
    and associated accuracies
2 Operating characteristic under reference conditions
3 Operating time under reference conditions
4 Harmonic restraint characteristics

Sets out the performance conditions for the relays and parameters whose values the manufacturer has to state. Suggests ways to present the properties and performance of these relays. Relevant to relays designed to discover faults, especially in a.c. generators, motors and transformers. Does not apply, however, to relays designed for busbar protection, or to current differential relays.