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1、BRITISH STANDARD BS 787-2:1968 Incorporating Amendment No. 1 Specification for Mining type flameproof gate-end boxes Part 2: Gate-end boxes with air-break circuit-breakers (for use on 3-phase a.c. circuits up to 650 volts) Licensed Copy: London South Bank University, London South Bank University, Fr
2、i Dec 08 12:21:24 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 787-2:1968 This British Standard, having been approved by the Colliery Requisites Industry Standards Committee and endorsed by the Chairman of the Engineering Divisional Council, was published under the authority of the General Council
3、on 30 August 1968 BSI 01-2000 The following BSI references relate to the work on this standard: Committee reference CRE/16 Draft for comment 66/9630 ISBN 0 580 00277 2 Co-operating organizations The Colliery Requisites Industry Standards Committee, under whose supervision this British Standard was p
4、repared, consists of representatives from the following Government and scientific and industrial organizations: Association of Mining Electrical and Mechanical Engineers* British Electrical and Allied Manufacturers Association* British Steel Industry Federation of Associations of Mining Equipment Ma
5、nufacturers Institution of Electrical Engineers Institution of Mechanical Engineers Institution of Mining Engineers Mechanical Handling Engineers Association Ministry of Power* National Association of Colliery Managers National Coal Board* The Government department and industrial organizations marke
6、d with an asterisk in the above list were directly represented on the committee entrusted with the preparation of this British Standard. Amendments issued since publication Amd. No.Date of issueComments 422February 1970Indicated by a sideline in the margin Licensed Copy: London South Bank University
7、, London South Bank University, Fri Dec 08 12:21:24 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 787-2:1968 BSI 01-2000i Contents Page Co-operating organizationsInside front cover Forewordii 1Scope1 2Definitions1 3Service conditions3 4Ratings3 5Marking3 6Design and construction4 7Tests8 8Informatio
8、n to be supplied to the manufacturer with the enquiry10 Appendix A Metric values12 Figure 1 Arrangement of busbar chamber end flange, terminals and interconnections13 Figure 2 Busbar interconnecting trunk14 Figure 3 Skid coupling arrangement15 Figure 4 Busbar end cover16 Licensed Copy: London South
9、Bank University, London South Bank University, Fri Dec 08 12:21:24 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 787-2:1968 ii BSI 01-2000 Foreword This standard makes reference to the following British Standards: BS 88, Cartridge fuses of voltage ratings up to 660 volts. BS 159, Busbars and busbar
10、connections. BS 229, Flameproof enclosure of electrical apparatus. BS 279, 100-ampere flameproof plugs and sockets (restrained type). BS 542, Cable glands and sealing boxes for association with apparatus for use at mines. BS 862, Air-break circuit-breakers (including totally-enclosed and flameproof
11、types) for voltages not exceeding 660 volts. BS 936, Oil circuit-breakers for medium-voltage alternating-current systems. BS 1259, Intrinsically safe electrical apparatus and circuits for use in explosive atmospheres. BS 3101, Intrinsically safe remote-control circuits associated with restrained plu
12、gs and sockets for use in coal mines. BS 3454, 3.3 kV 300 A interchangeable bolted flameproof cable couplers and adaptors (including 660 V 300 A adaptors) primarily for use in mines. This British Standard has been prepared, under the authority of the Colliery Requisites Industry Standards Committee,
13、 to standardize the main features of gate-end boxes used primarily in coal mining in the United Kingdom. It is recognized that the term “gate-end box” is quite general and may be applied to boxes containing different essential components, such as contactors, circuit-breakers, lighting transformers e
14、tc., depending upon the purpose for which they are to be used. BS 787 was first issued in 1938, and has been revised and re-issued as BS 787-1:1965 to cover gate-end boxes in which the essential apparatus is an air-break electrically operated contactor. This additional specification, designated as B
15、S 787-2, extends the scope of the original BS 787 by covering gate-end boxes in which the essential apparatus is an air-break circuit-breaker. It is envisaged that additional parts of this British Standard will be issued to cover other forms of gate-end boxes, such as lighting units and drill units.
16、 NOTEWhere metric equivalents have been given (see Appendix A), the figures in imperial units are to be regarded as the standard. The metric conversions are approximate. More accurate conversions should be based on the tables in BS 350-1, “Conversion factors and tables”. A British Standard does not
17、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 immunity from legal obligations. Summary of pages This document comprises a front cover, an inside fro
18、nt cover, pages i and ii, pages 1 to 16 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 the inside front cover. Licensed Copy: London South Bank University, London South Bank University,
19、Fri Dec 08 12:21:24 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 787-2:1968 BSI 01-20001 1 Scope This British Standard specifies requirements for mining type flameproof gate-end boxes with air-break circuit-breakers for use on 3-phase a.c. circuits up to 650 volts. 2 Definitions For the purposes of
20、 this British Standard the following definitions apply: 2.1 gate-end box a flameproof enclosure containing electrical apparatus such as control gear, switchgear and/or protective gear, designed primarily for use underground NOTEIn this particular instance the apparatus is essentially an air-break ci
21、rcuit-breaker with associated equipment to provide control and protection of other electrical apparatus. 2.2 isolator a mechanical device capable of opening or closing a circuit, under conditions of no load or negligible current 2.3 air-break circuit-breaker a device, hand or power operated, capable
22、 of making, carrying and breaking currents in air, at substantially atmospheric pressure, under normal circuit conditions and also making, carrying for a specified time, and breaking currents under specified abnormal conditions such as those of short-circuit 2.4 cable sealing and dividing box a box
23、designed to receive and protect the end of the cable, with provision for sealing the conductors and the insulating material of the cable with a suitable compound, and having a cable gland for attaching the cable to the box, together with any terminals provided for connection to the conductors of the
24、 cable within the box. The box may form part of, or be detachable from, the apparatus with which it is associated 2.5 detachable cable sealing box a cable sealing box so designed that it can be detached from associated apparatus without cutting the cable and without disturbing the sealing 2.6 cable
25、coupling unit (flit plug) a unit consisting of a cable sealing box and cable gland together with means for connecting the cable conductors to insulated contact tubes within the sealing box, which is designed to receive the cable; to provide room to spread and connect the cores; to protect the cores;
26、 to allow for the attachment of the cable gland; to provide for sealing the insulating materials of the cable, and to facilitate ready connection to or disconnection from a similar unit or other apparatus 2.7 cable coupler adaptor a device used to connect a cable coupling unit to apparatus. It may e
27、ither be separate from or integral with the flameproof enclosure of the apparatus to which the cable coupling unit is to be connected for the purposes of this standard, the term “adaptor” also includes the unit to connect other types of cable terminations to apparatus 2.8 restrained plug and socket
28、a plug and socket, the two portions of which, when engaged, are designed to be held together by an operating bolt, or a screwed union ring, or some other equivalent device. Such a device enables the plug to be readily inserted or withdrawn Licensed Copy: London South Bank University, London South Ba
29、nk University, Fri Dec 08 12:21:24 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 787-2:1968 2 BSI 01-2000 2.9 bolted plug and socket a plug and socket, the two portions of which, when fully engaged, are designed to be held together by one or more bolts or screws, or studs and nuts, in such a way tha
30、t they cannot be disengaged without the use of tools 2.10 flameproof enclosure an enclosure for electrical apparatus that will withstand, without injury, any explosion of the prescribed flammable gas that may occur within it, under practical conditions of operation within the rating of the apparatus
31、 (and recognized overloads, if any, associated therewith) and will prevent the transmission of flame such as will ignite the prescribed flammable gas which may be present in the surrounding atmosphere (see 7.2.4) 2.11 intrinsically safe circuit a circuit in which any electrical sparking that may occ
32、ur in normal working under the conditions specified by the certifying authority, and with the prescribed components, is incapable of causing an ignition of the prescribed flammable gas or vapour (see 7.2.4) 2.12 rating the value assigned by the maker to some limits of performance under certain speci
33、fied conditions known as the “rated conditions” 2.13 local control external control by means of an external handle for a hand operated circuit-breaker, or by push button for an electrically operated circuit-breaker 2.14 remote control control by means of a manually operated switch or push button loc
34、ated at a point separate from the gate-end box 2.15 automatic control control by means of any device other than a manually operated switch or push button 2.16 sequence interlocking means by which operation is made dependent on the fulfilment of other prescribed conditions 2.17 overcurrent release a
35、device that causes the circuit-breaker to open the circuit automatically when the current exceeds the predetermined value at which the release has been adjusted to operate 2.18 inverse time lag overcurrent release a device that retards the tripping of the circuit-breaker by a time inversely dependen
36、t upon the magnitude of the overcurrent 2.19 undervoltage release a device which causes the circuit-breaker to open the circuit if the voltage falls below a predetermined value 2.20 shunt release a device which causes the circuit-breaker to open when energized from a source of voltage that may be in
37、dependent of the circuit in which the circuit-breaker is connected Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:21:24 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 787-2:1968 BSI 01-20003 3 Service conditions Gate-end boxes in accordance with this specific
38、ation are suitable, within the limits of their ratings, for installations where the service conditions are not more severe than the following: 1) Ambient temperature. A peak value not exceeding 40 C with an average value not exceeding 35 C over 24-hour periods. 2) Altitude. An altitude not exceeding
39、 3 300 feet (1 000 m) above sea level. NOTEWhen a gate-end box intended for service at high altitudes is tested near sea level, the limits of temperature rise, as indicated in 6.16, should be reduced by 1 % for each 1 000 feet (300 m) above sea level at which the circuit-breaker is intended to work
40、in service. The correction does not apply for altitudes below 3 300 feet (1 000 m). 4 Ratings 4.1 Voltages. The maximum voltage shall be 650 volts. The following supply voltages shall be regarded as standard: 400, 440, 500, 550, 600 and 650 volts. Boxes designed for other than the standard voltages
41、up to 650 volts, provided they satisfy all other requirements specified herein, shall be deemed to comply with this standard. Standard boxes shall be suitable for a voltage variation at least 10 % below and at least 6 % above the declared voltages of the supply for which they are designed, subject a
42、gain to the maximum of 650 volts. 4.2 Supply frequencies. The standard frequency shall be 50 Hz(c/s). Gate-end boxes designed for other frequencies within the range of 2560 Hz(c/s), provided they satisfy all other requirements specified herein, shall be deemed to comply with this standard. 4.3 Curre
43、nts 4.3.1 Current rating of boxes. The preferred continuous current ratings of boxes shall be: 200, 300, 400 amperes Boxes designed for other ratings, provided they satisfy all other requirements specified herein, shall be deemed to comply with this standard. 4.3.2 Current rating of busbars. The cur
44、rent rating of busbars, where fitted, shall be at least equal to the circuit-breaker rating, with a minimum rating of 300 amperes. 5 Marking 5.1 Nameplates. All gate-end boxes shall be permanently marked with the following particulars: 1) The name of the manufacturer or his agent. 2) Manufacturers t
45、ype or reference. 3) Manufacturers serial number. 4) Maximum rated current in amperes. 5) Making capacity peak (kA). 6) Breaking capacity (kA). 7) Voltage or voltage range. 8) Frequency. 9) The number of the flameproof certificate and the number or numbers indicating the group of gases and vapours c
46、overed by the certificate. 10) A reproduction of the registered flameproof mark (if the manufacturer holds a licence to apply this mark), or any other mark required by the Ministry of Power. 11) Where applicable the intrinsic safety certificate details as required by the Ministry of Power. 12) Addit
47、ional marking as may be required by any other certifying authority. 5.2 Terminals. Terminal markings, if required, for incoming and outgoing connections shall be agreed between the manufacturer and the purchaser. 5.3 Busbar interconnecting trunks. All busbar interconnecting trunks (see 6.3) shall be
48、 permanently marked with the following particulars: Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:21:24 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 787-2:1968 4 BSI 01-2000 1) Manufacturers name or trade mark. 2) Manufacturers type or reference. 5.4 Busba
49、r end covers. All busbar end covers (see 6.4) shall be marked with the following particulars: 1) Manufacturers name or trade mark. 2) Manufacturers type or reference. 5.5 Diagrams. Diagrams of connections, which shall be durable and legible, shall be securely attached in an accessible position within the main chamber. 6 Design and construction A gate-end box in accordance with this specification shall comply with the requirements of BS 2291) (Note) and shall have been certified, by the Ministry of Power, as flameproof for Group 1 gases (methane/firedamp). The
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