ISO 20949:2018

INTERNATIONAL ISO
STANDARD 20949
First edition
2018-11
Aircraft — Smart contactor — General
requirements
Aéronefs — Contacteurs intelligents — Exigences générales
Reference number
©
ISO 2018
© ISO 2018
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ii © ISO 2018 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements . 3
4.1 Detail specification sheets. 3
4.2 Materials . 4
4.3 Construction . 4
4.4 Terminals . 4
4.4.1 Main terminals . 4
4.4.2 Auxiliary terminals . 5
4.5 Enclosures . 5
4.5.1 General. 5
4.5.2 Open enclosures . 6
4.5.3 Enclosed enclosures (ventilated explosion-proof) . 6
4.5.4 Sealed (other than hermetically) enclosures . 6
4.5.5 Hermetically sealed enclosures . 6
4.5.6 Grounding of enclosures . 6
4.6 Installation clearances . 6
4.7 Terminal marking . 6
4.8 Terminal covers and barriers . 6
4.9 Mounting . 7
5 Design characteristics . 7
5.1 General . 7
5.2 Control signal . 8
5.3 Status signals for smart contactors . 8
5.4 Fail-safe characteristics . 8
6 Operating characteristics . 8
6.1 General operating characteristics . 8
6.2 Timing sequence. 8
6.3 Operating voltage . 9
6.3.1 General. 9
6.3.2 Pickup voltage . 9
6.3.3 Dropout voltage . 9
6.4 Electrical characteristics . 9
6.4.1 General. 9
6.4.2 Contact voltage drop.10
6.4.3 Quiescent power dissipation .10
6.4.4 Control signals .10
6.5 Contact bounce, operating and release time .11
6.6 Dielectric strength.11
6.7 Insulation resistance .11
6.8 Overload characteristics .12
6.8.1 General.12
6.8.2 Trip characteristics with the overload condition .12
6.8.3 Circuit breaker compatibility .12
6.9 Ground Fault Interrupt characteristics .12
6.10 Trip-free characteristics.12
6.11 Life .12
7 Environmental conditions and test procedures .13
8 Qualification Tests .13
8.1 General .13
8.2 Visual and mechanical examination .14
8.3 Timing sequence.15
8.3.1 Turn-off time .15
8.3.2 Turn-on time .15
8.4 Operating voltage .16
8.4.1 General.16
8.4.2 Pickup voltage .16
8.4.3 Dropout voltage .16
8.5 Electrical characteristics .16
8.5.1 General.16
8.5.2 Contact voltage drop.17
8.5.3 Quiescent power dissipation .17
8.5.4 Control signals .17
8.6 Contact bounce, operating and release times .19
8.7 Dielectric withstanding voltage .21
8.8 Insulation resistance .21
8.9 Overloads .21
8.9.1 Trip characteristics with the overload condition .21
8.9.2 Circuit breaker compatibility .22
8.10 Ground Fault Interrupt characteristics .
...