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1、BRITISH STANDARD OBSOLESCENT JULY 1983 BS G 142:1953 Incorporating Amendment No. 1 Specification for Heavy duty, electro-magnetically operated, single-pole circuit-breakers for extra-low voltage d.c. systems in aircraft UDC 621.316.57:629.13.066 Licensed Copy: London South Bank University, London So
2、uth Bank University, Sat Dec 09 02:22:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 142:1953 This British Standard, having been approved by the Aircraft Industry Standards Committee and endorsed by the Chairman of the Engineering Divisional Council, was published under authority of the General
3、Council of the Institution on 19 January 1953 BSI 02-2000 ACE/30 ISBN 0 580 34526 2 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 itse
4、lf 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 6 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendme
5、nt table on the inside front cover. Amendments issued since publication Amd. No.Date of issueComments 4301July 1983Indicated by a sideline in the margin Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:22:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 142:
6、1953 BSI 02-2000i Contents Page Section 1. General requirements 1Scope1 2General construction1 3Rating and overload characteristics1 Section 2. Particular requirements 4Operation1 5Mechanical latching1 6Operating voltage1 7Economy or hold-on coils or resistances1 8Self re-closing1 9Terminals and ele
7、ctrical connections1 10Current carrying contacts2 11Arcing contacts2 12Auxiliary contacts2 13Vibration, acceleration, climatic proofing and flameproofing2 14Marking2 Section 3. Tests 15General2 A. Type tests 16Millivolt drop test2 17Vibration test2 18Acceleration test2 19Climatic test2 20Functioning
8、 tests3 21High voltage tests3 22Millivolt drop test3 23Operating tests3 24Temperature rise3 25Flameproof test3 26Self re-closing at low temperature3 27Calibration of overload trip3 28High temperature test3 29Overload trip tests3 30Making-and-breaking capacity tests4 31Endurance tests4 B. Production
9、tests 32Operating tests4 33Overload trip5 34High voltage tests5 35Selection of samples5 36Overload calibration tests5 37Interpretation of results5 Figure 1 Envelope of current-time characteristic curves6 Table 1 Current ratings1 Table 2 Voltage drop and load inductance4 Licensed Copy: London South B
10、ank University, London South Bank University, Sat Dec 09 02:22:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:22:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 142:1953 BSI 02-20001 Obsolescent (by A
11、mendment No. 1) The need for the equipment covered by this British Standard has been reviewed and it has been decided that, in the interests of rationalization, it should be regarded as obsolescent and not therefore used for new designs. The standard will be withdrawn in due course. Section 1. Gener
12、al requirements 1 Scope This British Standard specifies the requirements for electro-magnetically operated, single-pole circuit-breakers, with contacts rated at not less than 50 amperes, for use in a nominal 24 volt D.C. system in aircraft. 2 General construction The unit shall comply with the requi
13、rements, where applicable, of BS G 100, “General requirements for electrical equipment and indicating instruments for aircraft.” The circuit-breakers shall be electro-magnetically operated from a nominal 24 volt D.C. system. An over-current tripping device shall be incorporated, also suitable arcing
14、 contacts and/or arc quenching devices. 3 Rating and overload characteristics a) The normal rating of the circuit-breaker shall be in accordance with Table 1. b) Each circuit-breaker shall be adjusted to carry its normal rated current continuously, in an ambient temperature of 75 C., without over-he
15、ating or automatic tripping. c) Each circuit-breaker shall have current-time characteristics within the envelope shown in Figure 1 at all ambient temperatures within the range + 50 C. to 40 C. Table 1 Current ratings Section 2. Particular requirements 4 Operation The operating device shall be design
16、ed to give a clean make-and-break on all contacts. No detrimental contact bounce or chatter shall occur under any conditions. Contacts shall be self-cleaning or corrosion-resisting. The operation of the circuit-breaker shall not be affected by the attitude of mounting or fixing. 5 Mechanical latchin
17、g If the circuit-breaker is of the mechanically latched type, the normal method of opening shall be by electromagnetic means with separate electrical connections. Means shall also be provided for manual release in case of emergency. The operation of any latching or release device shall not affect th
18、e operation or calibration of the overload trip. 6 Operating voltage The minimum operating voltage of the closing or trip devices shall not exceed 21 volts with the coils hot and in an ambient temperature of + 75 C. At all ambient temperatures in the range + 75 C. to 40 C. the circuit-breaker shall
19、not release at any voltage across the operating device above 10 volts. It shall release satisfactorily at a voltage of not less than 4 volts at an ambient temperature of 40 C. 7 Economy or hold-on coils or resistances Hold-on coils or windings may be fitted if required. Economy resistances shall not
20、 be used. 8 Self re-closing The circuit-breaker shall be so designed that, after tripping on overload, it cannot re-close automatically at any temperatures above 50 C. 9 Terminals and electrical connections a) Terminals shall be shrouded and so arranged that, when the cable is connected, the cable l
21、ug cannot move in relation to its terminal post under any conditions. b) Terminals and electrical connections for any auxiliary circuit shall be physically separated from the load terminals. Normal rated current Maximum rated current make-and-break amp. 50 75 100 150 200 300 400 amp. 1 000 1 500 2 0
22、00 3 000 4 000 6 000 8 000 NOTEIn the interests of safety in the aircraft, where the prospective current is greater than the maximum rated current shown in Table 1, some form of current limiting device or back-up protection should also be inserted. Licensed Copy: London South Bank University, London
23、 South Bank University, Sat Dec 09 02:22:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 142:1953 2 BSI 02-2000 10 Current carrying contacts Current carrying contacts shall be capable of carrying a) the normal rated current continuously, and b) the momentary maximum rated currents, as shown in Ta
24、ble 1. 11 Arcing contacts Arcing contacts shall be capable of making and breaking a momentary overload of maximum rated current. Alternatively, arc quenching devices shall be capable of functioning satisfactorily under the same conditions. 12 Auxiliary contacts Auxiliary contacts, if fitted, shall b
25、e capable of carrying their full rated load continuously at 28.5 volts D.C. 13 Vibration, acceleration, climatic proofing and flameproofing The circuit-breaker shall be designed and constructed to satisfy the requirements of BS G 100 in respect of: a) Vibration Grade II b) Acceleration Grade I c) Cl
26、imatic proofing Grade I d) Flameproofing. 14 Marking The following information shall be clearly and indelibly marked on each circuit-breaker: a) BS G 142. b) Manufacturers name or identification c) Manufacturers type number d) Current and voltage rating. Section 3. Tests 15 General Tests shall be ma
27、de to prove compliance with all the requirements of this British Standard. It is not intended or recommended that complete tests shall be made on every circuit-breaker supplied. Three kinds of tests, therefore, are specified, as follows: A. TYPE TESTS (Clauses 16 to 31) which shall be made on repres
28、entative samples of each particular design and size of circuit-breaker. B. PRODUCTION TESTS, which are subdivided into: I. Routine tests (Clauses 32 to 34) which shall be made on every circuit-breaker manufactured in compliance with this British Standard. II. Tests on samples (Clauses 35 to 37) whic
29、h shall be made on selected sample batches. The tests prescribed in Clauses 16 to 22, shall be performed in that order on the same circuit-breaker. Tests in Clauses 23 to 31 inclusive may be made on another circuit-breaker or circuit-breakers. Every circuit-breaker used during the type tests shall b
30、e tested in accordance with Clause 21, and before testing, in accordance with Clause 16, and after testing, in accordance with Clause 22. Where one circuit-breaker only is used for tests in accordance with Clauses 23 to 31, the breaking capacity tests (Clause 30) shall be performed last. No further
31、tests need be carried out (for the purpose of this specification) on any circuit-breaker submitted to this test. The tests shall be made with the covers on, and, unless otherwise stated, with an electrical supply of 28.5 volts D.C. Connecting cables, not less than two feet long, of the smallest size
32、 appropriate to the rating of the circuit-breaker shall be used, together with suitable cable lugs. Where an ambient temperature is specified for a test, the equipment shall be allowed to reach that temperature before the test is made. A. Type tests 16 Millivolt drop test A test shall be made in an
33、ambient temperature of 15 25 C. to determine the millivolt drop across the contacts and also across the thermal element of a new and unused circuit-breaker when carrying the normal rated current. 17 Vibration test The circuit-breaker shall be subjected to the Grade II vibration test specified in BS
34、G 100. 18 Acceleration test The circuit-breaker shall be subjected to the Grade I acceleration test specified in BS G 100. 19 Climatic test The circuit-breaker shall be subjected to cycles of temperature, pressure and humidity as specified in the Grade I climatic test in BS G 100. Licensed Copy: Lon
35、don South Bank University, London South Bank University, Sat Dec 09 02:22:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 142:1953 BSI 02-20003 20 Functioning tests The functioning tests specified in the vibration, acceleration and climatic tests in BS G 100, shall each consist of: a) Ten operati
36、ons, make-and-break, within one minute, with 21.0 volts applied to the operating device. The rated load at 28.5 volts D.C. shall be applied to the load terminals, and an appropriate load at 28.5 volts D.C. applied to any auxiliary terminals, b) repeat a), but with 28.5 volts applied to the operating
37、 device, and, c) satisfactory automatic tripping within the limits of the curve shown in Figure 1, with 28.5 volts D.C. applied to the operating device, and with 200 per cent rated current applied to the main terminals, d) satisfactory operation of the emergency hand release, if fitted. 21 High volt
38、age tests a) A test voltage of 500 volts r.m.s. 50 c/s shall be applied for one minute between the terminals with the circuit-breaker in the open position. If the case is of metal, the test voltage shall then be applied for one minute between the terminals connected together and the case with the co
39、ntacts open and closed. If the circuit-breaker has an all-insulated case, the latter test shall be made with the circuit-breaker mounted upon its metallic panel or in its metallic enclosure. The voltage shall be increased and decreased gradually. b) Immediately after the tests in a), the insulation
40、resistance shall be measured with direct current at 500 volts, and shall be not less than 100 megohms, except for the coil, for which the insulation resistance shall be not less than 30 megohms. For this test the circuit-breaker shall be arranged as in a). 22 Millivolt drop test The millivolt drop t
41、est specified in Clause 16 shall be repeated and the values obtained shall not have increased by more than ten millivolts. 23 Operating tests Tests shall be made (in an ambient temperature of 15 25 C.) to ensure that the circuit-breaker complies with the requirements of Clause 6. 24 Temperature rise
42、 a) The circuit-breaker shall be shielded from extraneous air currents, and shall carry 115 per cent normal rated current in an ambient temperature of 15 25 C. for two hours without tripping. b) The temperature rise on any part of the circuit-breaker shall comply with the relevant requirements of BS
43、 G 100. 25 Flameproof test The circuit-breaker shall be subjected to the flameproof test specified in BS G 100. 26 Self re-closing at low temperature The circuit-breaker shall be tripped on overload and kept in an ambient temperature of 50 2 C. for one hour during which time it shall not re-close au
44、tomatically. 27 Calibration of overload trip Tests shall be made at ambient temperatures of + 50 2 C., + 20 2 C., and 40 2 C., to obtain current-time characteristic curves. The curves shall be within the envelope shown in Figure 1. 28 High temperature test a) The circuit-breaker shall carry normal r
45、ated current for one hour in an ambient temperature of 75 2 C. without tripping. The current shall be increased to 200 per cent normal rated current and the circuit-breaker shall trip automatically. b) At loads of 200 per cent and 300 per cent normal rated current, in an ambient temperature of + 20
46、20 C., automatic tripping shall occur at values within ten per cent of those obtained under the test in Clause 27. 29 Overload trip tests a) The circuit-breaker shall be connected in a circuit controlling a load of 200 per cent normal rated current in an ambient temperature of 15 25 C. Fifty operati
47、ons shall be performed on the circuit-breaker as follows: Close; trip automatically; close within twenty seconds of automatic trip. b) Within twenty seconds of the last operation of the test cycle in a) the circuit-breaker shall be closed, and it shall carry 115 per cent normal rated current for one
48、 hour in an ambient temperature of 15 25 C. without automatic tripping. Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:22:51 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 142:1953 4 BSI 02-2000 c) At loads of 200 per cent and 300 per cent normal rated curr
49、ent, in an ambient temperature of + 20 2 C., automatic tripping shall occur at values within ten per cent of those obtained under Clause 27. 30 Making-and-breaking capacity tests The tests in a) and b) below shall be carried out, firstly with the circuit-breaker installed as indicated in Clause 15 and subsequently with the connections on the circuit-breaker reversed in an ambient temperature of 15 25 C. at an atmospheric pressure of 2.72 lb/sq. in. (corresponding to an altitude of 40 000 feet). If the cir