so NTERNATIONAL STANDARD 1549 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEXIYHAPOHA OPrAHW3ALNS IO CTAHIAPTH3ALIWH.ORGANISATION INTERNATIONALE DE NORMALISATION Aircraft -- Precision fuse-links - Type B Aeronefs - Porte-fusible de precision - Type B First edition - 1976-03-01 ISO 1549-1976 (E) UDC 629.7.064.5 : 621.316.923.1 Ref. No. iSO 1549-1976 (E) Descriptors : aircraft equipment, electric fuses, fuse-links, precision equipment, specifications, dimensions, ratings, tests Price based on 12 pages Copyright International Organization for Standardization Not for Resale FOREWORD IsO (the International Organization for Standardization) is a woridwide federation of national standards institutes (ISO Member Bodies). The work of developing International Standards is carried out through ISo Technical Committees. Every Member Body interested in a subject for which a Technical Committee has been set up has the right to be represented on that Committee. Internationat organizations, governmental and non-governmental, in liaison with sO, aiso take part in the work. Draft Internationai Standards adopted by the Technical Committees are circulated to the Member Bodies for approval before their acceptance as International Standards by the ISO Council. Prior to 1972, the results of the work of the Technical Committees were published as iso Recommendations; these documents are now in the process of being transformed into International Standards. As part of this process, Technical Committee ISO/TC 20 has reviewed ISO Recommendation R 1549 and found it technically suitabie for transformation. International Standard ISO 1549 therefore iSO Recommendation R 1549 was approved by the Member Bodies of the following countries : Australia Israel Switzerland Belgium Italy Thailand Canada New Zealand Turkey Czechoslovakia United Kingdom Peru Egypt, Arab Rep. of South Africa, Rep. of Spain Greece The Member Bodies of the following countries expressed disapprova! of the Recommendation on technical grounds : Germany Netherlands U.S.S.R. The Member Bodies of the following countries disapproved the transformation of ISO/R 1549 into an International Standard : Germany U.S.S.R. @ International Organization for Standardization, 1976 : Printed in Switzerland Copyright International Organization for Standardization ed without license from IHS Not for Resale ISO 1549-1976 (E) INTERNATIONAL STANDARD Aircraft -- Precision fuse-links -- Type B 1 SCOPE AND FIELD OF APPLICATION 4 GENERALREQUIREMENTS This International Standard specifies the dimensions and The fuse-links shall comply with the requirements of performance requirements for a range of precision fuse- ISO 1547. links suitabie for use in aircraft electrical systems having frequency characteristics conforming to voltage and ISO/R222, , at any ambient temperature from -65 to + 85 c, and all altitudes from 0 to 24 400 m. (See also 5 DIMENSIONS ISO1540.) The dimensions of the fuse-links shall comply with tabie 1 for the ferrule type or table 2 for the tag type. 2 REFERENCES ISO/R 222, Voltages for aircraft electrical systems. 6 CURRENT, VOLTAGE AND BREAKING-CAPACITY ISO/R 469, Dimensions and conductor resistance of general purpose electrical cables with copper conductors for RATINGS aircraft. The current ratings, the voltage ratings and the breaking- ISO/R 474, Performance requirements for general purpose capacity ratings of the fuse-links shall be in accordance electrical cables with copper conductors for aircraft. with those listed in table 3. IsO 1540, Aerospace Aircraft electrical systems Characteristics. 1 ) 7 TIME/CURRENT CHARACTERISTICS ISO 1547, Aircraft Precision fuse-links - General requirements. The pre-arcing time/current characteristics of the fuse-links shall be within the appropriate envelope curves shown in IEC Publication 269, Low-voltage fuses -- Part I : General the annex. requirements. 3 TERMINOLOGY 8 TESTS The terminoiogy used in this International Standard is in conformity with IEC Publica