1、BRITISH STANDARD AEROSPACE SERIES BS3G197: 1982 (Superseding BS2G197:1978) Specification for Stud-type terminal blocks for terminations on aircraft electric cables UDC 629.7.064.5:621.315.684BS3G197:1982 This BritishStandard, having been prepared under the directionof the Aerospace Standards Committ
2、ee, was published under the authority ofthe Board of BSI and comesintoeffect on 30 July1982 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference ACE/6 Draft for comment81/71094DC ISBN 0 580 12713 3 Foreword This BritishStandard, prepared under the directi
3、on of the Aerospace Standards Committee, is a revision of BS2G197:1978 which is withdrawn. BS 2G197:1978 specified a range of terminal blocks that were interchangeable with the most commonly used types specified in BS G197:1967. The standard also redefined the flammability requirements for the termi
4、nal blocks which necessitated some changes in their physical properties. For reasons of interchangeability, imperial dimensions have been retained forFigure 1 to Figure 4. Metric dimensions are given in parentheses. This revision introduces some changes to the dimensional requirements of the standar
5、d that have been found by experience to be necessary. Some changes have been made to the allocation of samples and sequence of testing for type approval. The list of test fluids has also been updated. The importance of toxicity has been recognized, but no suitable test has been found to date which h
6、as proved acceptable for this standard. Pending the development of such a test, the materials from which the terminal blocks are manufactured should present the minimum hazard from toxic fumes and smoke. The specified temperature ratings for terminal blocks have been selected to permit compatibility
7、 with maximum conductor temperatures of aircraft causes commonly in use. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer i
8、mmunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to 17 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on t
9、he inside front cover. Amendments issued since publication Amd. No. Date of issue CommentsBS3G197:1982 BSI 12-1999 i Contents Page Foreword Inside front cover Section 1. General 1 Scope 1 2 References 1 3 Definitions 1 Section 2. Design 4 Design and outline dimensions 1 5 Type and number of terminal
10、s 2 6 Screw threads and stiffnuts 2 7 Properties of dielectrics 2 8 Terminal retention 2 9 Voltage and frequency 2 10 Temperature and altitude 2 11 Vibration and acceleration 2 12 Humidity, temperature and pressure 2 13 Tropical exposure 2 14 Mould growth 2 15 High temperature ageing 2 16 Flammabili
11、ty 2 17 Resistance to fluids 2 18 Marking 2 19 Declarations 3 Section 3. Type tests 20 Standard test conditions 3 21 Recording of results 3 22 Test specimens 3 23 Voltage proof 3 24 Insulation resistance 3 25 Vibration 3 26 Acceleration 4 27 Humidity, temperature and pressure 4 28 Tropical exposure
12、4 29 Mould growth 5 30 High temperature ageing 5 31 Terminal retention: axial loading 5 32 Terminal retention: torque loading 5 33 High temperature failure 5 34 Flammability 5 35 Resistance to fluids 6 36 Mechanical properties of dielectrics 7 Section 4. Production routine tests 37 Inspection 7 38 V
13、oltage proof and insulation 7 39 Terminal retention 7 Appendix A Preparation of loomed specimen for test 16 Figure 1 Double row terminal block types440 UNJC,632 UNJC,1032 UNJF. Terminals2,4,6,10 and20 10BS3G197:1982 ii BSI 12-1999 Page Figure 2 Single row terminal block (in line feet) types440 UNJC,
14、632 UNJC,1032 UNJF. Terminals1,2,3,5 and10 11 Figure 3 Single row terminal block (offset feet) types440 UNJC,632 UNJC,1032 UNJF. Terminals1,2,3,5 and10 12 Figure 4 Terminal area details 13 Figure 5 Specimen mounting 14 Figure 6 Flame position 15 Figure 7 Typical specimen preparation detail 17 Table
15、1 Stiffnut rundown torque limits 7 Table 2 Type approval tests, allocation of samples and sequence of tests 8 Table 3 Terminal stud axial loads (standard conditions) 8 Table 4 Terminal stud axial loads (hot condition) 8 Table 5 Torque loading of terminal assemblies 8 Table 6 Test fluids 9 Table 7 Nu
16、mber and gauge of terminations 16BS3G197:1982 BSI 12-1999 1 Section 1. General 1 Scope This BritishStandard specifies requirements for the design and performance of terminal blocks with studs4 UNJC,6 UNJC and10 UNJF rolled threads for use with ring tongue terminal ends on aircraft cables. 2 Referenc
17、es Reference is made in this standard to the following publications. BS 3G100, General requirements for equipment for use in aircraft. BS G204, Copper terminal ends for crimping to electric cables with copper conductors. BS M26, Chemical preparations for chemical closets (re-circulation type) for ai
18、rcraft. BS 5S80, Specification for high chromium-nickel corrosion-resisting steel billets, bars, forgings and parts. BS580, Trichloroethylene. BS805, Specification for toluenes 1) . BS1595, isoPropyl alcohol. BS2782, Methods of testing plastics Part3:Mechanical properties Methods320A to320F: Determi
19、nation of tensile strength, elongation and elastic modulus Method351A: Determination of Charpy impact resistance of rigid plastics and ebonite (Charpy impact flexural test). BS4084, Specification for UNJ threads, with controlled root radius, for aerospace: inch series. BS4487, Inhibited1,1,1-trichlo
20、roethane (methylchloroform). BS6001, Sampling procedures and tables for inspection by attributes. The latest editions of these standards shall be used. NOTEThe latest revision of an Aerospace Series standard is indicated by a prefix number. 3 Definitions For the purposes of this BritishStandard the
21、following definitions apply. 3.1 termination a permanent formation of an electric cable conductor with a terminal end 3.2 terminal end a ring tongue cable tag or lug NOTEThese are of the general type specified in BS G204. 3.3 terminal block a formation of terminals that are housed in an insulating m
22、aterial 3.4 terminal a stud and nut assembly that secures terminal ends 3.5 total operating temperature the ambient temperature plus the temperature rise due to conducted heat from connected cables Section 2. Design 4 Design and outline dimensions 4.1 The outline dimensions of a range of terminal bl
23、ocks are shown in Figure 1, Figure 2 and Figure 3. Dimensions for the terminal area are shown inFigure 4. NOTEFor reasons of interchangeability, imperial dimensions have been retained for these figures. Metric dimensions are given in parentheses. 4.2 Terminals and fittings shall be separated by barr
24、iers to provide electrical and mechanical isolation such that the barriers shall exceed the height of the studs by at least1mm and shall be so designed that any uninsulated sections of the cable terminal ends on adjacent studs cannot be made to contact each other. 4.3 The design of the terminal shal
25、l be such that the palm diameter of suitable terminal ends complying with BS G204 shall not exceed the diameter of the shoulder. The shoulder shall also stand proud of the surrounding insulation to ensure that no part of the terminal end will be held in compression with the insulation as part of the
26、 electrical joint. The design of the terminal block shall be such that suitable terminal ends complying with BS G204 shall be capable of being clamped to the shoulder with the crimp barrel facing up or down and, in the case of a single row block, from either side of the block. 4.4 The terminal block
27、 may be provided with a cover as an accessory. The cover shall be made of an insulating material and shall comply with the performance requirements of this standard. 1) Contained in one volume, BS135,BS 458,BS 805 “Specification for benzene, xylenes and toluenes”.BS3G197:1982 2 BSI 12-1999 5 Type an
28、d number of terminals The preferred numbers of terminals in a row are1,2,3,5 and10 of the same size stud and there shall not be more than two rows. 6 Screw threads and stiffnuts 6.1 Studs shall be of corrosion resistant steel complying withBS 5S80 or equivalent; the rolled class3A unified threads sh
29、all comply with BS4084. 6.2 All nuts shall be stiffnuts incorporating an integral washer and shall be within the range of rundown torque limits given in Table 1 when used with studs complying with6.1. 7 Properties of dielectrics The form and material of terminal blocks shall provide for a robust con
30、struction with special regard being paid to the strength and resilience of terminal barriers. Material(s) shall, when tested in standard form, have an elongation at break complying with36.2 or an impact resistance complying with36.3. Preference shall be given to good elongation at break performance
31、unless the upper design temperature selected in accordance with10.1 dictates the use of a more rigid material. 8 Terminal retention The insert strength of terminals shall be such that the requirements for axial loads and torque loads specified in clause31 and clause32 are satisfied. 9 Voltage and fr
32、equency The blocks shall be suitable for use on aircraft a.c. and d.c. electrical systems having the characteristics specified inBS 3G100-3. 10 Temperature and altitude 10.1 The blocks shall be suitable for continuous use at a total operating temperature from65 C to an upper level which shall be sel
33、ected from the following temperatures. +105 C,+135 C,+150 C,+200 C,+260 C 10.2 The manufacturer shall declare the failuretemperature of the terminal block, whenoverheated, when tested in accordance withclause33. Failure temperature is defined as the lower of the temperatures at which: a) the termina
34、l block fails to comply with31.3 when an axial load of50% of the appropriate load listed in Table 4 is applied; or b) the insulation resistance when measured in accordance with clause24 falls to0.2M7. 10.3 The blocks shall be suitable for use at altitudes from sea level to21340m. 11 Vibration and ac
35、celeration A terminal block with terminations and cables fitted as specified in22.4 shall be capable of meeting the vibration conditions specified in clause25 and of withstanding an acceleration of25g nas specified in clause26. If a cover is provided as an accessory, it shall be fitted for these tes
36、ts. 12 Humidity, temperature and pressure The blocks shall comply with clause27. 13 Tropical exposure The blocks shall comply with clause28. 14 Mould growth The blocks shall comply with clause29. 15 High temperature ageing The blocks shall comply with clause30. 16 Flammability The blocks shall compl
37、y with34.5 and34.6. 17 Resistance to fluids The blocks shall comply with35.2 and35.3. 18 Marking 18.1 Blocks shall be identified in accordance withBS 3G100-1. 18.2 Each terminal position shall be numbered either as shown in Figure 1 or in a manner that is both legible and unambiguous. 18.3 Each row
38、of double row terminal blocks shall beidentified by the letters L and R as shown inFigure 1 or in a manner that is both legible andunambiguous.BS3G197:1982 BSI 12-1999 3 19 Declarations The manufacturer shall prepare a Declaration of Design and Performance (DDP) as specified in BS3G100-1 for each ty
39、pe and size range of terminal block. The DDP shall give appropriate and specific cross-reference to the detailed requirements of this standard and shall, in addition, include particulars of the following. a) Dielectric colour or colours. b) Ancillary fitments. (With commoning busbars fitted, the spe
40、cification requirements can be met,e.g.the required test number of terminations can be fitted as shown in Appendix A.) c) The electrical rating of commoning busbars. Section 3. Type tests 20 Standard test conditions Unless otherwise specified, the tests shall be carried out under normal atmospheric
41、conditions as follows. a) Temperature20 5 C. b) Relative humidity (r.h.)45% to75%. c) Atmospheric pressure860mbar to1060mbar 2) . 21 Recording of results Where measurements are required, the precise figures obtained shall be recorded in the type test report. 22 Test specimens 22.1 Selection of speci
42、mens. Type approval specimens shall be selected from a batch that has satisfied the routine inspection requirements of section4. 10 way blocks shall be taken as representative of the size range except that additionally a specimen of the smallest number of ways shall be used for the flammability test
43、 described in clause34. A difference in terminal form or dielectric material (including colour) shall constitute a change of type and may require separate type tests, at the discretion of the approving authority. 22.2 Sequence of tests. Table 2 shows the number of samples and the sequence in which e
44、ach sample is to be tested. 22.3 Insulation resistance, high voltage and resistance to fluid tests. Insulation resistance, high voltage and resistance to fluid tests shall be conducted on unwired blocks mounted directly on toa metal plate extending beyond the contour of theblock. 22.4 Wiring of spec
45、imens. Where tests indicate that electrical connections are to be made, the terminal block shall be mounted directly on to a metal plate extending beyond the contour of the block. The cable loom shall be as described inAppendix A. 22.5 Control samples. A minimum of two specimens from each type test
46、batch shall be identified and stored for record purposes. 23 Voltage proof Specimens shall be mounted as specified in22.3. Apotential of2000V r.m.s.50/60Hz a.c. shall be applied for a period of not less than5s between each adjacent pair of terminals and between each terminal and the earth plate. The
47、re shall be no audible or visible signs of breakdown of insulation or flashover and the specimen shall subsequently comply with clause24. 24 Insulation resistance 24.1 Sea level. With specimens mounted as specified in22.3, apply500 50V d.c. between the same test points as specified in clause23. Afte
48、r15s electrification or when a stable reading is reached the insulation resistance shall be measured. The minimum acceptable insulation resistance shall be200M7 between any terminal and earth and100M7 between any pair of adjacent terminals. 24.2 Altitude. The procedure in24.1 shall be repeated with
49、the specimen mounted in a chamber evacuated to a pressure equivalent to21340m. The acceptable insulation resistance shall be as specified in24.1. 25 Vibration 25.1 The specimen, when mounted and connected as specified in Appendix A, shall be subjected to vibration tests as described in BS3G100-2.3.1.These tests shall be specified for type A equipment, category5, subject to the conditions given in25.2 to25.4. 25.2 The specimen shall be vibrated in three axes as specified in4.2.1 ofBS 3G100-2.3.1 but for a total period of60h, this
