Overview
ISO 2315:1980 - "Aircraft - Two- and four-pole sealed electromagnetic relays, 2 A and 3 A - Clearance and fixing dimensions" is an International Standard that specifies the mechanical clearance and fixing dimensions for two‑ and four‑pole sealed electromagnetic change‑over relays with rated breaking capacities of 2 A and 3 A used in aircraft electrical power systems. This second edition (1980) replaces the 1974 edition and focuses on mechanical interface, mounting, and panel cut‑out requirements; electrical characteristics are noted as to be defined in a future standard.
Key topics and technical requirements
The standard provides detailed mechanical specifications to ensure interchangeability and reliable installation of aircraft relays:
- Unit and connection layouts for 2 A and 3 A relays, including provision for solder lugs, pins, and wire terminations.
- Base connection diagrams and marking requirements - at least one coil connection must be identified (e.g., colored bead) and preferred polarity may be indicated with a plus (+) sign.
- Fixing methods and multiple fixing types (illustrated types 1–5), with permissibility of round or slotted fixing holes and specified hole diameters and centre distances.
- Dimensional limits and tolerances, with figures (1–6) showing maximum and nominal dimensions such as panel mounting centres (e.g., N ≈ 27 mm), overall maxima (e.g., M ≤ 33.5 mm) and lead/terminal dimensions.
- Support panel drilling and cut‑outs (figure 7) for correct panel integration and clearance for two‑pole and four‑pole relays.
- Clear illustrations and dimension tables define standardised drilling patterns and tolerances to facilitate consistent aircraft installations.
Applications and users
ISO 2315:1980 is essential for professionals involved in aerospace electro‑mechanical integration:
- Aircraft electrical system designers and avionics engineers ensuring mechanical compatibility of relays with equipment racks and panels.
- Relay manufacturers and component suppliers designing sealed electromagnetic relays for aerospace use.
- Maintenance, modification and retrofit teams needing standardised panel cut‑outs and replacement part dimensions.
- Certification authorities and systems integrators verifying physical interchangeability across aircraft platforms.
Related standards
- This document was produced by ISO/TC 20 (Aircraft and space vehicles). The standard notes that electrical and performance characteristics of these relays will be covered by a future International Standard. For full compliance, use ISO 2315:1980 alongside applicable aerospace component and electrical standards.
Keywords: ISO 2315:1980, aircraft relays, electromagnetic relays, relay dimensions, clearance and fixing dimensions, two‑pole relay, four‑pole relay, 2 A relays, 3 A relays, support panel drilling, aerospace standards.
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