ISO 10296:1992

Overview

ISO 10296:1992 - Aircraft - Hybrid remote power controllers - General requirements - defines the general design and performance requirements for hybrid remote power controllers used on aircraft. These devices combine an electromagnetic (or combined electromagnetic/solid‑state) load‑switching element with a solid‑state control circuit to open/close electrical circuits and protect wiring and equipment against overloads and short circuits. The standard covers materials, construction, terminals, enclosures, mounting, control/status signals, operating behaviour and qualification/testing considerations.

Key topics and technical requirements

• Scope & definitions: Clear definitions for remote power controller, hybrid remote power controller and trip‑free operation (requires reset after a trip).
• Controller types: Two basic designs:
  • Type A - electromagnetic device performs the load switching; control circuit drives the contactor coil.
  • Type B - solid‑state switch performs the main make/break function; electromagnetic contacts carry current or break fault currents as required.
• Materials & construction: Non‑combustible materials that do not emit harmful gases or form conductive paths under test conditions; parts should support a practical shelf life (ideally ~20 years) unless otherwise declared.
• Terminals & mounting: Requirements for stud and plug‑in terminals, terminal barriers/covers, and threaded stud strength. Studs must accommodate hardware and retain minimum thread engagement; plug‑ins require gold over nickel plating where applicable.
• Enclosures & sealing: Three enclosure styles - ventilated explosion‑proof, hermetically sealed, and environmentally sealed (non‑hermetic) - with fill/gas and pressure guidelines for sealed units.
• Control & status signals: Inputs may include 28 V d.c. nominal, grounded control, TTL/CMOS logic or multiplexed impedance/status. Output status signals must indicate ON/OFF and recommended trip/fault indications; in Type B the contact state and solid‑state state must be represented (status timing error ≤ 10 ms).
• Operational behavior: Controllers must detect overcurrents, short circuits and phase imbalance (for three‑phase units), include a trip‑free feature, and operate across specified electrical/mechanical steady‑state and transient conditions.
• Environmental & qualification testing: References established environmental test procedures for airborne equipment.

Practical applications and users

• Typical users: avionics engineers, aircraft systems designers, OEM manufacturers of circuit protection and power distribution, certification authorities, and maintenance/repair organizations.
• Applications: Primary protection and remote switching of aircraft loads (avionics, electrical buses, motors, lighting), integration with aircraft control buses, modular power distribution panels, and retrofit/upgrades where reliability and fault isolation are required.

Related standards

• Normative references cited in the document include ISO 7137:1987 (aircraft environmental conditions and test procedures) and environmental/insulation test standards referenced for aircraft electrical equipment. Use ISO 10296:1992 together with current IEC/ISO electrotechnical and airborne equipment test standards when designing, qualifying or certifying aircraft power controllers.