1、BRITISH STANDARD BS 442:1950 Specification for Terminals For electrical apparatus For railway signalling purposesBS442:1950 This British Standard, having beenapproved by the ElectricalIndustry Standards Committee and endorsed bythechairman of the Engineering Divisional Council,was published underthe
2、authority of the GeneralCouncil on 30 December1950 BSI 11-1999 First published 1932 First revision December 1950 ISBN 0 580 00665 4 Co-operating organizations The Electrical Industry Standards Committee, 1)under whose supervision this British Standard was prepared, consists of representatives from t
3、he following Government departments and scientific and industrial organizations: Admiralty Air Ministry Association of Consulting Engineers incorporated Association of Supervising Electrical Engineers British Electrical and Allied Industries Research Association British Electrical and Allied Manufac
4、turers Association* British Electrical Development Association British Electricity Authority and Area Boards British Railways, The Railway Executive* Cable Makers Association Electric Lamp Manufacturers Association Electric Light Fittings Association Electrical Contractors Association (Incorporated)
5、 Electrical Contractors Association of Scotland Engineering Equipment Users Association General Post Office Institution of Electrical Engineers* Ministry of Fuel and Power Ministry of Labour and National Service (Factory Department) Ministry of Supply Ministry of Works National Physical Laboratory N
6、orth of Scotland Hydro-Electric Board Public Transport Association (Incorporated) Radio Industry Council The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted
7、 with the preparation of this British Standard: Crown Agents for the Colonies Federation of British Industries London Transport Executive Office of the High Commissioner for India Office of the High Commissioner for New Zealand Ministry of Transport National Union of Manufacturers Individual manufac
8、turers of Railway Signalling Apparatus 1) The Electrical Industry Standards Committee is the British National Committee of the International Electrotechnical Commission. Amendments issued since publication Amd. No. Date CommentsBS442:1950 BSI 11-1999 i Contents Page Co-operating organizations Inside
9、 front cover Foreword ii 1 Scope 1 2 Definition 1 3 General 1 4 Screw threads 1 5 Components and assembly 1 6 Materials and finish 1 Figure 1(a) 3 Figure 1(b) 3 Figure 1(c) 3 Figure 2 Components of nut type terminals 3 Figure 3 Screw type terminal 3 Figure 4 Dimensions of insulated screw type termin
10、al 4 Table 1 Dimensions of nut type terminals 2 Table 2 Dimensions of screw type terminals 2 Table 3 Dimensions of insulated screw type terminals 4BS442:1950 ii BSI 11-1999 Foreword This standard requires reference to the following British Standards: BS 57, B.A.bolts, screws, nuts and washers. BS 93
11、, British Association screw threads, with tolerances for sizes Nos.0to15B.A. BS 249, Brass bars (high speed screwing and turning). BS 488, Moulded insulating materials for general electrical purposes. This British Standard, first issued in1932, has now been revised in order to bring it into line wit
12、h recent developments in design and manufacturing of the terminals specified. 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 con
13、fer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to4 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 o
14、n the inside front cover.BS442:1950 BSI 11-1999 1 1 Scope This British Standard applies to the main terminals on electrical apparatus for railway signalling purposes, to which cables external to the apparatus are connected. It is not intended to apply to terminals inside the apparatus. Terminals of
15、both the nut and the screw type, and of the insulated screw type, are specified. 2 Definition For the purposes of this standard a terminal is defined as that portion of an apparatus which is intended for the reception of a conductor by means of which the apparatus may be connected electrically to an
16、other apparatus. 3 General The dimensions of British Standard signalling terminals (B.S.S.T.) shall be in accordance withTable 1 andTable 2 andFigure 1, Figure 2,Figure 3 orFigure 4, for the particular type of terminal concerned. These dimensions shall apply to the finished, i.e.plated, components.
17、4 Screw threads Subject to the nuts or screws being rotatable without the aid of a spanner or screwdriver, their screw threads shall comply with the sizes and the tolerances laid down for0 B.A.and2 B.A.bolts and nuts inB.S.93, “British Association screw threads with tolerances for sizes Nos.0 to15 B
18、.A.” 5 Components and assembly The complete terminals shall be assembled according to one of the following arrangements: 0 B.A.and2 B.A.nut type comprising: a) one bolt, two binding nuts, three washers and one clamp nut according toFigure 1(a) andFigure 2. b) one stud, two binding nuts, two washers
19、and means of fixing bolt or nut securely to the terminal base according toFigure 1(b) andFigure 2, in a manner such that the bolt or stud will not become loose in service and, at the same time, will provide a metal contact surface of an area not less than that of a clamp nut of the appropriate size.
20、 The metal contact surface shall be treated to remove all burrs and sharp edges so that it will not damage the conductor. 0 B.A.and2 B.A.screw type (including insulated screw type) comprising: a) one screw and two washers in accordance withFigure 1(c) andFigure 3. b) one insulated screw and two wash
21、ers (one of which may be a locking washer of a type approved by the purchaser) in accordance withFigure 1(c) andFigure 4. The metal component into which the screw is fitted shall have a metal contact surface of an area not less than that of a clamp nut of the appropriate size. 6 Materials and finish
22、 All metal components shall be made of brass complying with BS249, “Brass bars (high speed screwing and turning)” or other equivalent material approved by the purchaser, and shall be nickel plated. The thickness of plating shall be not less than0.0002in.and not more than0.0005in. Washers shall be tr
23、eated to remove burrs and sharp edges so that they will not damage the conductors. The ends of bolts and screws may, at the option of the manufacturer, be finished with a radius (approximately equal to the diameter of the shank), or a chamfered flat, or with the normal finish obtained during manufac
24、ture in the process of thread rolling, and shall be free from burrs. The insulating head of the insulated screw type terminal shall be of moulded insulating material complying with GradeIII orIIIX of BS488, “Moulded insulating materials for general electrical purposes.”BS 442:1950 2 BSI 11-1999 Tabl
25、e 1 Dimensions of nut type terminals (See Figure 1 andFigure 2) Table 2 Dimensions of screw type terminals (SeeFigure 2 for washer andFigure 3 for screw) Designation Binding nut (Ref.1) Clamp nut (Ref.2) Washer (Ref.3) Bolt or stud (Ref.4) A B D E F A C D G H J Dia. L. t.p.i. in. in. in. in. in. in.
26、 in. in. in. in. in. in. in. 0 B.A. 2 B.A. 0.500 0.365 0.313 0.281 0.236 0.185 0.188 0.188 0.438 0.313 0.500 0.365 0.188 0.188 0.236 0.185 0.250 0.190 0.563 0.421 0.056 0.048 0.236 0.185 1 0.875 25.4 31.3 NOTEThe dimensions given are maximum and are subject to normal manufacturing tolerances. Design
27、ation Screw Washer A B D H J L min. R (rad.) Y max. t.p.i. G H J in. in. in. in. in. in. in. in. in. in. in. 0 B.A. 2 B.A. 0.472 0.365 0.165 0.130 0.236 0.185 0.048 0.048 0.089 0.069 0.375 0.313 0.02 0.02 0.060 0.048 25.4 31.3 0.250 0.190 0.563 0.421 0.056 0.056 NOTE 1The screw dimensions have been
28、taken fromBS57, “B.A.bolts, screws, nuts and washers.” Tolerances given in that standard are applicable to these dimensions except where otherwise stated. NOTE 2The washer dimensions are subject to normal manufacturing tolerances.BS 442:1950 BSI 11-1999 3 Figure 1(a) Figure 1(b) Figure 1(c) Assembly
29、 of nut type terminals. Numbers relate to references in Table 1. Assembly of screw type terminals Figure 2 Components of nut type terminals Figure 3 Screw type terminal Letters relate to references in Table 1. Letters relate to references in Table 2.BS442:1950 4 BSI 11-1999 Table 3 Dimensions of ins
30、ulated screw type terminals Dimension Size in. A 0.500 B 0.438 C 0.500 D 0.236 E 0.031 F 0.125 G 0.375 H 0.688 J 0.969 K 0.438 L 0.625 M 0.313 N 0.094 P 0.25 Q max. 0.06 R max. 0.02 Screw designation 0 B.A. threads perinch 25.4 SeeTable 2 andFigure 2 for washer. NOTEThe dimensions given in the above
31、 table are subjected to normal manufacturing tolerances. Figure 4 Dimensions of insulated screw type terminalblankBS 442:1950 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK vi
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