ISO 20949-2018 PDF
Name in English:
St ISO 20949-2018
Name in Russian:
Ст ISO 20949-2018
Original standard ISO 20949-2018 in PDF full version. Additional info + preview on request
Full title and description
ISO 20949:2018 — Aircraft — Smart contactor — General requirements. Defines the designation, general design and performance requirements, and test methods for smart contactors intended for use in aircraft electrical power systems; a smart contactor combines a switching driving circuit with a power switch to provide protection, control action and status information.
Abstract
This standard specifies definitions, design titles, general requirements and test methods to determine the performance of smart contactors for aircraft electrical power systems, covering the switching-driving circuit, the power switch and provision of status information.
General information
- Status: Published (international standard; reviewed and confirmed in 2024).
- Publication date: 16 November 2018 (ISO edition 1, 2018).
- Publisher: International Organization for Standardization (ISO).
- ICS / categories: 49.060 — Aerospace electric equipment and systems.
- Edition / version: Edition 1 (2018).
- Number of pages: 24 pages (official ISO publication).
Scope
ISO 20949:2018 applies to smart contactors used in aircraft electrical power systems. It covers terminology and definitions, titles of design and general requirements, and test methods intended to determine performance (including control-input compatibility, status signalling and built‑in test provisions) of the combined switching-driver and power‑switch assembly.
Key topics and requirements
- Definitions and terms specific to aircraft smart contactors (scope and component descriptions).
- General design and performance requirements for the switching-driving circuitry and the power switch.
- Required test methods to verify performance under electrical, environmental and operational conditions.
- Control-signal compatibility requirements (examples: nominal 28 V d.c., grounded input, TTL/CMOS logic levels, a 10 mA source at 1–12 V for backwards compatibility with circuit-breaker style inputs).
- Status signalling and built-in test (BIT) requirements — at least one status signal (preferred: switch status) and BIT means to indicate normal/abnormal conditions of key parts.
- Operational stability requirements (stabilization times after power-up, after momentary outages and during supply-voltage drops) and behaviour required to clear faults and allow supply recovery.
- Normative references and referenced environmental/insulation test standards applicable to aircraft electrical equipment.
Typical use and users
Used by avionics and aircraft electrical-system designers, component manufacturers (smart contactor and power‑switch suppliers), test laboratories, procurement teams specifying supplier requirements, and engineers responsible for integration and qualification of aircraft electrical power distribution equipment. It informs design, test and contract requirements for contactors that include intelligent control and status functions.
Related standards
Normative references and related documents commonly associated with ISO 20949 include standards for aircraft electrical-system characteristics and environmental/testing procedures such as ISO 1540, ISO 7137 and ISO 2678 (insulation/high-voltage tests), as well as legacy documents on relays and contactors used in aerospace applications (for example ISO 5867‑1). Designers also consider aircraft environmental and EMC test standards (e.g., RTCA/DO‑160 series) when qualifying hardware for installation.
Keywords
smart contactor, aircraft contactor, power switch, switching-driving circuit, built-in test (BIT), status signal, avionics, electrical power system, test methods, ISO 20949.
FAQ
Q: What is this standard?
A: ISO 20949:2018 is an international standard that specifies general requirements and test methods for smart contactors used in aircraft electrical power systems.
Q: What does it cover?
A: It covers terminology, design and performance requirements, control-signal compatibility, status-signal and BIT provisions, stabilization and fault‑clearing behaviour, plus test methods to verify these aspects.
Q: Who typically uses it?
A: Avionics/electrical engineers, contactor and component manufacturers, test houses and procurement or systems-integration teams working on aircraft power-distribution hardware.
Q: Is it current or superseded?
A: The 2018 edition (Edition 1) is published and was reviewed/confirmed in 2024; it remains the current ISO edition. (ISO records the standard as confirmed in 2024.)
Q: Is it part of a series?
A: ISO 20949 is a standalone standard addressing smart contactors, but it is used alongside other aerospace electrical and test standards (for example ISO 1540, ISO 7137, ISO 2678 and relevant relay/contactors documents) when specifying and qualifying aircraft electrical hardware.
Q: What are the key keywords?
A: Smart contactor; contactor; aircraft; avionics; power switch; switching-driving circuit; built-in test (BIT); status signal; test methods; ISO 20949.