ISO/TC 20/SC 1/WG 13 - Characteristics of aircraft electrical systems (Revision of ISO 1540)

This document specifies the general requirements and test methods for auto-transformer rectifier units (ATRUs) for use in aircraft electrical systems. This document is mainly applicable to ATRUs of 18-pulse and 24-pulse types.

This document specifies the definitions, titles of design and general requirements and test methods to determine the performance of smart contactors for use in aircraft electrical power systems. The smart contactor consists of a switching driving circuit and a power switch for protection, action on control signals, and providing status information.

ISO 6858:2017 specifies the electrical output characteristics and interface requirements between an aircraft and ground support electrical supplies. This includes all external electric power generation facilities, provided as part of a central source or in point-of-use application. Requirements for safety features are also included. Performance and safety issues under regional control are not addressed in this document. Requirements for ground traffic control purposes, such as towing points, identification and warning lights, etc. are also excluded. The electrical characteristics relate to nominal 28 V DC and either 115/200 V or 230/400 V three-phase, 400 Hz AC outputs measured at the aircraft attaching connector as indicated in Figure 1.

ISO 1540:2006 specifies the characteristics of electrical power supplied to the terminals of electrical utilization equipment installed in an aircraft. It is intended to support the interface definition for user equipment designed to accept electrical power on a variety of new civil aircraft applications, such as those certified via the Technical Standard Order (TSO) certification process. It might not be desirable for equipment targeted to a single application or specific military application to follow ISO 1540:2006 because of the penalties associated with multi-application. ISO 1540:2006 also attempts to provide background to the development of these requirements that may be useful to those designing and/or integrating modern aircraft electrical systems. The delivered quality of this electrical power is a result of the combined characteristics of the electrical power source, distribution and user equipment. While only user equipment restrictions are specifically defined, background to key source and distribution equipment interfaces are identified in order to support development of the overall system. A wide variety of electrical supply types and distribution parameters have been considered, as may be found on both small and large transport aircraft. Sources considered include physically rotating and static types, provided either on-aircraft, or as part of the ground support equipment. Distribution voltages addressed are nominal 14 V, 28 V and 42 V d.c.; nominal 26 V a.c., 400 Hz, one-phase; nominal 115/200 V rms and 230/400 V rms a.c., both one-phase and three-phase, at either a nominal 400 Hz constant frequency (CF), or over a variable frequency (VF) range which includes 400 Hz.

Specifies the characteristics of electrical power supplied to the terminals of airborne equipment and defines limits for those aspects of utilization equipment which may adversely affect the characteristics of electrical power supplied to other equipment. Its purposes to achieve compatibility between airborne utilization equipment and aircraft electrical power supplies. Ground support electrical power supplies forms the subject of a separate International Standard.