1、BRITISH STANDARD CONFIRMED APRIL1993 BS787-4:1972 Specification for Mining type flameproof gate-end boxes Part 4: Gate-end boxes for drilling machines (for use on3-phase a.c.circuits up to650V)BS787-4:1972 This BritishStandard, having been approved by the Mining andQuarrying Requisites Industry Stan
2、dards Committee, was published under the authorityof the Executive Boardon 25January1972 BSI01-2000 The following BSI references relate to the work on this standard: Committee reference MQE/16 Draft for comment 70/34177 ISBN 0 580 06867 6 Co-operating organizations The Mining and Quarrying Requisite
3、s Industry Standards Committee, under whose supervision this BritishStandard was prepared, consists of representatives from the following Government department and scientific and industrial organizations: Association of Mining Electrical and Mechanical Engineers* British Electrical and Allied Manufa
4、cturers Association* British Steel Industry Council of Underground Machinery Manufacturers Department of Trade and Industry* Engineering Equipment Users Association Federation of Manufacturers of Construction Equipment and Cranes Institute of Quarrying Institution of Mechanical Engineers Institution
5、 of Mining Engineers National Coal Board* The Government department and industrial organizations marked with an asterisk in the above list were directly represented on the committee entrusted with the preparation of this BritishStandard. Amendments issued since publication Amd. No. Date CommentsBS78
6、7-4:1972 BSI 01-2000 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Service conditions 2 4 Ratings 2 5 Marking 3 6 Design and construction 3 7 Tests 7 8 Information to be supplied to the manufacturer with the enquiry 8 Appendix A Metric values 9
7、 Figure 1 Arrangement of busbar chamber end flange, terminalsandinterconnections 10 Figure 2 Busbar interconnecting trunk 11 Figure 3 Skid coupling arrangement 12 Figure 4 Busbar end cover 13BS787-4:1972 ii BSI 01-2000 Foreword This standard makes reference to the following BritishStandards: BS88, C
8、artridge fuses of voltage ratings up to660volts. BS159, Busbars and busbar connections. BS171, Power transformers. BS229, Flameproof enclosure of electrical apparatus. BS542, Cable glands and sealing boxes for association with apparatus for use at mines. BS587, Motor starters and controllers. BS775,
9、 Contactors. BS861, Air-break switches and isolators. BS1259, Intrinsically safe electrical apparatus and circuits for use in explosive atmospheres. BS1395, 30-ampere flameproof plugs-and-sockets and cable-couplers. BS2613, Electrical performance of rotating electrical machines. BS3101, Intrinsicall
10、y safe remote-control circuits associated with restrained plugs and sockets for use in coal mines. BS3454, 3.3kV300A interchangeable bolted flameproof cable couplers and adaptors (including660V300A adaptors) primarily for use in mines. BS3871, Miniature and moulded case circuit-breakers. This Britis
11、hStandard has been prepared, under the authority of the Mining and Quarrying Requisites Industry Standards Committee, to standardize the main features of gate-end boxes used primarily in coal mining in the UnitedKingdom. It is recognized that the term “gate-end box” is quite general and may be appli
12、ed to boxes containing different essential components, such as contactors, circuit-breakers, lighting transformers, etc., depending upon the purpose for which they are to be used. BS787 was issued in1938, and has been revised and re-issued as BS787-1, BS787-2 and BS787-3, to cover gate-end boxes in
13、which the essential apparatus is, respectively, an air-break electrically operated contactor, an air-break circuit-breaker and a lighting transformer. This additional specification, designated BS787-4, extends the scope of the original BS787 by covering gate-end boxes in which the essential apparatu
14、s is for controlling electrically operated drilling machines. NOTEAlthough metric equivalents have been given (seeAppendix 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 relevant tables in
15、 BS350, “Conversion factors and tables”. 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 immunity from legal obligations.
16、Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to13 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.BS787-4:197
17、2 BSI 01-2000 1 1 Scope This BritishStandard specifies requirements for flameproof gate-end boxes designed primarily for use in the mining industry, on3-phasea.c.circuits up to650V, for controlling one or two electrically-operated drilling machines. NOTEThe titles of the BritishStandards referred to
18、 in this standard are listed on pageii. 2 Definitions For the purposes of this BritishStandard, 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 NO
19、TEFor the purposes of this standard the apparatus is essentially a transformer, frequency changer or frequency transformer, with contactor(s) and associated equipment to provide control and protection of drilling machines. 2.2 isolating switch a switch which isolates a circuit and is capable of brea
20、king not less than its rated current at rated voltage 2.3 contactor a device suitable for repeatedly opening and closing the circuits of electrical apparatus; it functions electro-magnetically, the speed of make and of break being independent of the operator 2.4 transformer a piece of apparatus, wit
21、hout moving parts, which transforms alternating voltage in one winding into alternating voltage in one or more other windings, usually at different values 2.5 frequency changer a rotating machine for convertinga.cat one frequency and voltage toa.c.at another frequency and voltage NOTEWhere a static
22、device is used without a rotating machine, the term “frequency transformer” should be used to distinguish it from a frequency changer. 2.6 cable 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 co
23、ntact 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; 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 di
24、sconnection 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 be either 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
25、this standard, the term “adaptor” also includes the unit to connect other types of cable termination to apparatus 2.8 cable sealing and dividing box a box 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 s
26、uitable 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 cable within the box. The box may form part of, or be detachable from, the apparatus with which it is associated 2.9 detachable cable sealing bo
27、x a cable sealing box so designed that it can be detached from associated apparatus without cutting the cable and without disturbing the sealing 2.10 flameproof enclosure a flameproof enclosure for electrical apparatus is one that will withstand, without injury, any explosion of the prescribed flamm
28、able gas that may occur within it, under practical conditions of operation within the rating of the apparatus (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 a
29、tmosphere (see6)BS787-4:1972 2 BSI 01-2000 2.11 rating the value assigned by the maker to some limits of performance under certain specified conditions known as the “rated conditions” 2.12 restrained plug and socket a plug and socket, the two portions of which, when engaged, are designed to be held
30、together by an operating bolt, a screwed union ring, or some other equivalent device. Such device enables the plug to be readily inserted or withdrawn 2.13 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 o
31、r screws, or studs and nuts, in such a way that they cannot be disengaged without the use of tools 2.14 intrinsically safe circuit a circuit in which any electrical sparking that may occur in normal working, under the conditions specified by the certifying authority, and with the prescribed componen
32、ts, is incapable of causing an ignition of the prescribed flammable gas or vapour 2.15 remote control control by means of a manually operated switch or push-button located at a point separate from the gate-end box 2.16 overcurrent release a device that causes the contactor to open the circuit automa
33、tically when the current exceeds the predetermined value at which the release has been adjusted to operate NOTEThe preferred term “overcurrent” is used throughout this standard, but in certain other BritishStandards to which reference is made the term “overload” may be used when referring to these d
34、evices. 2.17 inverse time lag overcurrent release a device that retards the opening of the contactor by a time inversely dependent upon the magnitude of the overcurrent 2.18 instantaneous short circuit release a device which operates without intentional time delay, at a predetermined current, to cau
35、se the supply to be cut off from a circuit 3 Service conditions Gate-end boxes in accordance with the requirements of this standard are suitable, within the limits of their ratings, for installations where the service conditions are not more severe than the following. 3.1 Ambient temperature. A peak
36、 value not exceeding40 C with an average value not exceeding35 C over24h periods. 3.2 Altitude. An altitude not exceeding3300ft(1000m) 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 in6.16, should
37、be reduced by1% for each1000ft(300m) above sea-level at which the gate-end box is intended to work in service. The correction does not apply for altitudes below3300ft(1000m). 4 Ratings 4.1 Voltages. The maximum voltage shall be650V. Standard gate-end boxes shall be suitable for a voltage variation a
38、t least10% below and at least6% above the declared voltage of the supply for which they are designed, subject again to the maximum of650V. 4.2 Supply frequencies. The standard frequency shall be50Hz. Gate-end boxes designed for other frequencies within the range of42Hz to60Hz, provided they satisfy
39、all other requirements specified herein, shall be deemed to comply with the requirements of this standard. 4.3 Output voltages. The preferred no-load output voltage shall be125V3-phase. Other voltages may be used, subject to agreement between the purchaser and the manufacturer. 4.4 Output frequency.
40、 The standard output frequency shall be the same as the supply frequency, except when a frequency changer or frequency transformer is employed, when the output frequency shall be150Hz. 4.5 Output kV A. The standard output kV A shall be not less than1.25kV A for single circuit units or2.5kV A for dou
41、ble circuit units. 4.6 Current rating of busbars. The standard current rating of busbars, where fitted, shall be300A. Busbars of other ratings agreed between the manufacturer and the purchaser shall also be deemed to comply with the requirements of this standard.BS787-4:1972 BSI 01-2000 3 5 Marking
42、5.1 Nameplates. All gate-end boxes shall be permanently marked with the following particulars: 1) The registered trade name or trademark of the manufacturer or his agent. 2) Manufacturers type or reference. 3) Manufacturers serial number. 4) Maximum rated output in kV A. 5) Supply voltage or voltage
43、 range, and frequency. 6) Output voltage or voltage range, and frequency. 7) The number of the flameproof certificate and the number or numbers indicating the group of gases and vapours covered by the certificate. 8) A reproduction of the registered flameproof mark (if the manufacturer holds a licen
44、ce to apply this mark). 9) Where applicable, the intrinsic safety certificate details as required by the Department of Trade and Industry. 10) Additional marking as may be required by any other certifying authority. 5.2 Terminals. Terminal markings, if required, for incoming and outgoing connections
45、 shall be agreed between the manufacturer and the purchaser. 5.3 Busbar interconnecting trunks. All busbar interconnecting trunks (see6.3) shall be permanently marked with the following particulars: 1) Manufacturers name or trade mark. 2) Manufacturers type or reference. 5.4 Busbar end covers. All b
46、usbar end covers (see6.4) shall be marked with the following particulars: 1) Manufacturers registered name or trademark. 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
47、 chamber. 6 Design and construction A gate-end box in accordance with the requirements of this standard shall comply with the requirements of BS229 (seeNote) and shall have been certified by the Department of Trade and Industry as flameproof for Group I gases (methane/firedamp). The gate-end box may
48、 also be certified for any group of gas by an appropriate certifying authority as may be required. Unless otherwise agreed between the manufacturer and the purchaser, no external component shall be made of aluminium, magnesium or titanium, or of any alloys except those in which the total content of
49、these three constituents does not exceed15% by weight and in which the content of magnesium and titanium together does not exceed10% by weight. Neither shall any such component be painted or coated with preparations containing, in metallic form, any of the metals referred to above. NOTE 1These limitations have been imposed to avoid the hazards of incendive sparking due to friction between rusted steel or iron and the metals described. NOTE 2When applying for flameproof certification, it will be necessary for compliance with the requirements of BS229 for the manu
