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1、BRITISH STANDARD CONFIRMED APRIL 1993 BS 787-4:1972 Specification for Mining type flameproof gate-end boxes Part 4: Gate-end boxes for drilling machines (for use on 3-phase a.c. circuits up to 650 V) Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:21:44 GMT+0
2、0:00 2006, Uncontrolled Copy, (c) BSI BS 787-4:1972 This British Standard, having been approved by the Mining and Quarrying Requisites Industry Standards Committee, was published under the authority of the Executive Board on 25 January 1972 BSI 01-2000 The following BSI references relate to the work
3、 on this standard: Committee reference MQE/16 Draft for comment 70/34177 ISBN 0 580 06867 6 Co-operating organizations The Mining and Quarrying Requisites Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Governme
4、nt department and scientific and industrial organizations: Association of Mining Electrical and Mechanical Engineers* British Electrical and Allied Manufacturers Association* British Steel Industry Council of Underground Machinery Manufacturers Department of Trade and Industry* Engineering Equipment
5、 Users Association Federation of Manufacturers of Construction Equipment and Cranes Institute of Quarrying Institution of Mechanical Engineers Institution of Mining Engineers National Coal Board* The Government department and industrial organizations marked with an asterisk in the above list were di
6、rectly represented on the committee entrusted with the preparation of this British Standard. Amendments issued since publication Amd. No.DateComments Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:21:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 787-4:197
7、2 BSI 01-2000i Contents Page Co-operating organizationsInside front cover Forewordii 1Scope1 2Definitions1 3Service conditions2 4Ratings2 5Marking3 6Design and construction3 7Tests7 8Information to be supplied to the manufacturer with the enquiry8 Appendix A Metric values9 Figure 1 Arrangement of bu
8、sbar chamber end flange, terminals and interconnections10 Figure 2 Busbar interconnecting trunk11 Figure 3 Skid coupling arrangement12 Figure 4 Busbar end cover13 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:21:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI
9、 BS 787-4:1972 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 connections. BS 171, Power transformers. BS 229, Flameproof enclosure of electrical apparatus. BS 542, Cable
10、glands and sealing boxes for association with apparatus for use at mines. BS 587, Motor starters and controllers. BS 775, Contactors. BS 861, Air-break switches and isolators. BS 1259, Intrinsically safe electrical apparatus and circuits for use in explosive atmospheres. BS 1395, 30-ampere flameproo
11、f plugs-and-sockets and cable-couplers. BS 2613, Electrical performance of rotating electrical machines. BS 3101, Intrinsically safe remote-control circuits associated with restrained plugs and sockets for use in coal mines. BS 3454, 3.3 kV 300 A interchangeable bolted flameproof cable couplers and
12、adaptors (including 660 V 300 A adaptors) primarily for use in mines. BS 3871, Miniature and moulded case circuit-breakers. This British Standard has been prepared, under the authority of the Mining and Quarrying Requisites Industry Standards Committee, to standardize the main features of gate-end b
13、oxes 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, etc., depending upon the purpose for which they
14、 are to be used. BS 787 was issued in 1938, and has been revised and re-issued as BS 787-1, BS 787-2 and BS 787-3, to cover gate-end boxes in which the essential apparatus is, respectively, an air-break electrically operated contactor, an air-break circuit-breaker and a lighting transformer. This ad
15、ditional specification, designated BS 787-4, extends the scope of the original BS 787 by covering gate-end boxes in which the essential apparatus is for controlling electrically operated drilling machines. NOTEAlthough metric equivalents have been given (see Appendix A), the figures in imperial unit
16、s are to be regarded as the standard. The metric conversions are approximate. More accurate conversions should be based on the relevant tables in BS 350, “Conversion factors and tables”. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Stand
17、ards 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 front cover, pages i and ii, pages 1 to 13 and a back cover. This standard has been upda
18、ted (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, Fri Dec 08 12:21:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 787-4:1972 BSI 01-2
19、0001 1 Scope This British Standard specifies requirements for flameproof gate-end boxes designed primarily for use in the mining industry, on 3-phase a.c. circuits up to 650 V, for controlling one or two electrically-operated drilling machines. NOTEThe titles of the British Standards referred to in
20、this standard are listed on page ii. 2 Definitions For the purposes of 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 NOTE
21、For 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 breaki
22、ng 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, witho
23、ut 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 converting a.c at one frequency and voltage to a.c. at another frequency and voltage NOTEWhere a stati
24、c 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
25、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; 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
26、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 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 o
27、f 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
28、 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 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
29、box a cable sealing box so designed that it can be detached from associated apparatus without cutting the cable and without disturbing the sealing 2.10 flameproof enclosure a flameproof enclosure for electrical apparatus is one that will withstand, without injury, any explosion of the prescribed fla
30、mmable 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
31、 atmosphere (see 6) Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:21:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 787-4:1972 2 BSI 01-2000 2.11 rating the value assigned by the maker to some limits of performance under certain specified conditions known
32、 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 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 b
33、olted 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 that they cannot be disengaged without the use of tools 2.14 intrinsically safe circuit a circuit in which any ele
34、ctrical sparking that may occur 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 2.15 remote control control by means of a manually operated switch or push-
35、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 automatically when the current exceeds the predetermined value at which the release has been adjusted to operate NOTEThe preferred term “overcurrent” is used throu
36、ghout this standard, but in certain other British Standards to which reference is made the term “overload” may be used when referring to these devices. 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
37、 overcurrent 2.18 instantaneous short circuit release a device which operates without intentional time delay, at a predetermined current, to cause 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
38、 limits of their ratings, for installations where the service conditions are not more severe than the following. 3.1 Ambient temperature. A peak value not exceeding 40 C with an average value not exceeding 35 C over 24 h periods. 3.2 Altitude. An altitude not exceeding 3 300 ft (1 000 m) above sea-l
39、evel. 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 ft (300 m) above sea-level at which the gate-end box is intended to work in service. The correction does not app
40、ly for altitudes below 3 300 ft (1 000 m). 4 Ratings 4.1 Voltages. The maximum voltage shall be 650 V. Standard gate-end boxes shall be suitable for a voltage variation at least 10 % below and at least 6 % above the declared voltage of the supply for which they are designed, subject again to the max
41、imum of 650 V. 4.2 Supply frequencies. The standard frequency shall be 50 Hz. Gate-end boxes designed for other frequencies within the range of 42 Hz to 60 Hz, provided they satisfy all other requirements specified herein, shall be deemed to comply with the requirements of this standard. 4.3 Output
42、voltages. The preferred no-load output voltage shall be 125 V 3-phase. Other voltages may be used, subject to agreement between the purchaser and the manufacturer. 4.4 Output frequency. The standard output frequency shall be the same as the supply frequency, except when a frequency changer or freque
43、ncy transformer is employed, when the output frequency shall be 150 Hz. 4.5 Output kV A. The standard output kV A shall be not less than 1.25 kV A for single circuit units or 2.5 kV A for double circuit units. 4.6 Current rating of busbars. The standard current rating of busbars, where fitted, shall
44、 be 300 A. Busbars of other ratings agreed between the manufacturer and the purchaser shall also be deemed to comply with the requirements of this standard. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 12:21:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 78
45、7-4:1972 BSI 01-20003 5 Marking 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
46、 A. 5) Supply voltage or voltage 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 (i
47、f the manufacturer holds a licence 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 i
48、ncoming 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 permanently marked with the following particulars: 1) Manufacturers name or trade mark. 2) Manufacturers type or refere
49、nce. 5.4 Busbar end covers. All busbar end covers (see 6.4) 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 chamber. 6 Design and construction A gate-end box in accordance with the requirements of this standard shall comply with the requirements of BS 229 (see Note) and shall have been certified by the Department of Trade and Industry as f
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