ISO/CD 25898

Aircraft — Autotransformer Unit (ATU) — General Requirements

Scope

This standard specifies the general requirements of the Autotransformer Unit (ATU) for use in aircraft electrical power systems, including materials, design and construction, size and mass, color, processing quality and appearance quality, markings, performance, acoustical noise, reliability, maintainability and interchangeability. Test procedures and Qualification inspection requirements are also specified.
This standard is applicable to the ATU with bidirectional conversion of 230/400 volt alternating current (AC, 360Hz~800Hz) and 115/200 volt power in aircraft electrical power systems. The ATUs consists of autotransformer and associated circuitry for protection, and action of control signals.