Overview
ISO 24071:2022 - "Aircraft - Auto-transformer rectifier units (ATRUs) - General requirements" specifies general requirements and test methods for auto-transformer rectifier units (ATRUs) used in aircraft electrical systems. The standard is primarily applicable to 18‑pulse and 24‑pulse ATRUs. It defines design, material, performance and environmental criteria and provides a framework for qualification inspection to ensure safe, reliable AC-to-DC conversion with multipulse phase-shifting transformers that reduce harmonic currents.
Key topics and technical requirements
ISO 24071:2022 covers a comprehensive set of technical topics relevant to ATRU design, manufacture and testing, including:
- Specification sheets and their precedence where conflicts arise.
- Materials: selection criteria, corrosion protection for metals, restrictions (e.g., magnesium), and durability requirements for non-metal materials (moisture, fungus, salt spray resistance, flame and toxicity considerations).
- Design and construction: mechanical and electrical design principles, size and mass limits, processing and appearance quality, and marking/nameplate requirements.
- Performance requirements and tests: input/output power characteristics, efficiency, overload behavior, short‑circuit response, soft-starting, insulation resistance and dielectric strength, influence on input power systems, and electrical protection.
- Acoustical noise, reliability, maintainability and interchangeability requirements.
- Environmental conditions and test procedures aligned for airborne equipment and qualification inspection methods for production acceptance.
Practical applications
ISO 24071:2022 is intended to support:
- Design and qualification of ATRUs for more-electric aircraft (MEA) and all‑electric aircraft power systems.
- Integration of multipulse ATRUs as a cost-effective harmonic mitigation solution with lower mass and simpler structure compared to alternative suppression devices.
- Development of procurement specifications, factory acceptance tests, and maintenance/repair criteria for aircraft power conversion equipment.
Who should use this standard?
- ATRU and transformer manufacturers
- Aircraft electrical system engineers and integrators
- Avionics suppliers and OEMs
- Certification authorities, test laboratories and MRO organizations
- Procurement and quality assurance teams preparing specification sheets and qualification plans
Related standards
Normative references in ISO 24071:2022 include:
- ISO 1540:2006 - Characteristics of aircraft electrical systems
- ISO 7137:1995 - Environmental conditions and test procedures for airborne equipment
For full technical requirements and test procedures, obtain ISO 24071:2022 from your national standards body or ISO’s official publication channels.