1、BRITISH STANDARD AEROSPACE SERIES BS2G215-1: 1985 ISO8056-1: 1985 (Superseding British Standard G215:1972) Nickel-chromium and nickel-aluminium thermocouple extension cables for aircraft Part 1: Specification for conductors ISO title: Aircraft Nickel-chromium and nickel-aluminium thermocouple extens
2、ion cables Part1: Conductors General requirements and tests UDC 629.7:621.315.2 034.245:621.362.1BS2G215-1:1985 This British Standard, having been prepared under the directionof the Aerospace Standards Committee, was published under the authority ofthe Board of BSI and comesintoeffect on 31 December
3、1985 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference ACE/6 Draft for comment84/72756DC ISBN 0 580 14848 3 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Aerospace Standards Committee (AC
4、E/-) to Technical Committee ACE/6 upon which the following bodies were represented: BEAMA Ltd. British Rubber Manufacturers Association Civil Aviation Authority Electric Cable Makers Confederation Electronic Components Industry Federation Electronic Engineering Association Ministry of Defence Nation
5、al Supervising Inspectorate Society of British Aerospace Companies Limited Amendments issued since publication Amd. No. Date of issue CommentsBS2G215-1:1985 BSI 10-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope and field of application 1 2 References 1 3
6、Conductor materials 1 4 Conductor construction 1 5 Tests 1 Annex Methods for determining thermo-e.m.f. ofconductorwiresagainstplatinum 3 Figure 1 E.M.F. measurement by method of direct comparison against platinum 5 Figure 2 E.M.F. measurement by method using a substandard 6 Table 1 Details of nickel
7、-chromium and nickel-aluminium conductors 2 Table 2 Thermo-electric characteristics of nickel-chromium and nickel-aluminium conductors against platinum 2 Table 3 D.C. resistances of nickel-chromium and nickel-aluminium 2 Publications referred to Inside back coverBS2G215-1:1985 ii BSI 10-1999 Nationa
8、l foreword This British Standard, has been prepared under the direction of the Aerospace Standards Committee. It is identical with ISO8056-1:1975 “Aircraft Nickel-chromium and nickel-aluminium thermocouple extension cables Part1:Conductors General requirements and tests” published by the Internation
9、al Organization for Standardization (ISO). It supersedes British Standard G215:1972 which is withdrawn, and takes account of international agreement by Technical Committee ISO/TC20 in relation to the requirements of nickel-chromium and nickel-aluminium thermocouple extension cables for aircraft. Thi
10、s standard is restricted to the requirements for the conductors for the cables whereas British Standard G215:1972 used to cover the conductor and the insulation requirements for the complete cables. It is intended to cover the complete cable requirements by amendments to the British Standard Aerospa
11、ce cable standards using this standard as a cross-reference to cover the conductors for thermocouple extension cables. Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certa
12、in conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. Where the words “part of ISO8056”
13、 appear, referring to this standard, they should be read as “Part of British Standard2G215”. IPTS68 International Practical Temperature Scale of1968 is obtainable from HMSO. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are resp
14、onsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references International Standard Corresponding British Standard IEC Publication564:1977 BS5764:1979 Specification for d.c. bridges for measuring resistance (Ide
15、ntical) Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to6, an inside back cover 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 i
16、nside front cover.BS2G215-1:1985 BSI 10-1999 1 1 Scope and field of application This part of ISO8056 specifies the design requirements and tests for the conductors of thermocouple extension cables, using nickel-chromium and nickel-aluminium, for installation in aircraft temperature indicator and con
17、trol systems. Methods for determining the thermo-e.m.f. of conductor wires against platinum are given in the Annex . 2 References IEC Publication564, D.C. bridges for measuring resistance. IPTS68, International Practical Temperature Scale of1968. 3 Conductor materials Conductors for use in the const
18、ruction of thermocouple extension cables for aircraft shall be manufactured from bright, annealed, nickel-chromium (non-magnetic) wires and bright, annealed, nickel-aluminium (magnetic) wires. They shall comply with the requirements specified in Table 1 in terms of d.c. resistance and those in Table
19、 2 in terms of thermo-e.m.f. characteristics against platinum over the appropriate temperature range. Table 3 shows the resistances which have been assumed for nickel-chromium and nickel-aluminium wires in the calculation of d.c. conductor resistances. A maximum increase in length of4%, as a result
20、of stranding, has been assumed for the wires of each conductor. Each reel or coil of wire to be used in the manufacture of the conductors shall be tested in accordance with5.1 and5.2. Finished conductors shall be tested in accordance with5.3 and5.4. Each reel or coil of wire to be used in the manufa
21、cture of the conductors shall be tested in accordance with5.1 and5.2. Finished conductors shall be tested in accordance with5.3 and5.4. 4 Conductor construction The positive conductor shall consist of stranded, bright, annealed, nickel-chromium alloy wires complying with the requirements of clause3.
22、 The negative conductor shall consist of stranded, bright, annealed, nickel-aluminium alloy wires complying with the requirements of clause3. Joints in single wires shall be welded, brazed or silver-soldered, but the complete conductor shall not be joined. There shall be no kinks, broken wires or ot
23、her irregularities in the conductors. 5 Tests 5.1 Thermo-electric tests on conductor wires All wires, before stranding, shall be shown to comply with the requirements specified in Table 2 with respect to thermo-e.m.f. against platinum 1)over the range of temperature appropriate to the cable under ma
24、nufacture. Measurements shall be made on sample lengths taken from both ends of each reel or coil of wire. Amethod of direct comparison against platinum, as described in clauseA.1, shall be used where single samples are to be tested. Where large numbers of samples are to be tested, a differential me
25、thod, as described in clauseA.2, using substandards of nickel-chromium and nickel-aluminium as appropriate, may be employed. The substandards used shall have known, traceable thermo-electric characteristics against platinum. In the event of a dispute, the direct comparison method shall take preceden
26、ce. 5.2 Tests to determine the magnetic significance of conductor wires Each wire, before stranding, shall be checked with a magnet to determine its magnetic significance. Nickel-chromium wires shall be non-magnetic. Nickel-aluminium wires shall be magnetic. 5.3 Thermo-electric tests on conductors o
27、f finished cables A sample length shall be cut from one end of each reel or coil of finished cable. The thermo-electric characteristic against platinum of the conductor shall be checked differentially by the method using a substandard, as described in clauseA.2, over the temperature range of the cab
28、le. This characteristic shall comply with the requirements specified in Table 2. 5.4 Conductor resistance tests Each length of finished cable shall be checked for resistance at20 1 C by means of a suitable bridge, as described in IEC Publication564, of accuracy class no larger than0,5. Suitable prec
29、autions shall be taken to eliminate the effects of parasitic e.m.f.s. The appropriate limits of resistance are given in Table 1. 1) Platinum with a temperature coefficient of resistance not greater than0,003925 3ppm.BS2G215-1:1985 2 BSI 10-1999 Table 1 Details of nickel-chromium and nickel-aluminium
30、 conductors Table 2 Thermo-electric characteristics of nickel-chromium and nickel-aluminium conductors against platinum Table 3 D.C. resistances of nickel-chromium and nickel-aluminium wires Conductor Conductors of Nominal diameter of conductor nickel-chromium Ni-Cr(+) nickel-aluminiumNi-Al() Size N
31、umber and diameter of wires D.C. resistances at20 C max. min. max. min. mm 2 AWG a mm 7/1000m 7/1000m 7/1000m 7/1000m mm 0,4 0,6 1,0 1,2 2,0 3,0 5,0 22 20 18 16 14 12 10 19/0,15 19/0,2 19/0,25 19/0,3 37/0,25 37/0,32 61/0,32 2364 1330 851 591 437 267 162 1956 1100 705 489 362 220 133 932 524 336 234
32、172 106 64 771 434 278 193 143 86 52 0,75 1,00 1,25 1,50 1,75 2,20 2,85 a American Wire Gauge. Temperature Conductors of nickel-chromium(Ni-Cr) nickel-aluminium (Ni-Al) Thermo-e.m.f. against platinum max. min. max. min. C mV mV mV mV 100 50 0 50 100 150 200 250 300 2,287 1,271 0,060 1,413 2,873 4,41
33、8 6,029 7,689 9,382 2,167 1,151 0,060 1,293 2,753 4,298 5,909 7,569 9,262 1,386 0,738 0,060 0,730 1,342 1,839 2,228 2,463 2,945 1,266 0,618 0,060 0,610 1,222 1,719 2,108 2,583 2,825 Wire diameter Conductor of nickel-chromium(Ni-Cr) nickel-aluminium(Ni-Al) D.C. resistances max. min. max. min. mm 7/m
34、7/m 7/m 7/m 0,32 0,30 0,25 0,20 0,15 9,487 10,793 15,54 24,30 43,18 8,162 9,287 13,38 20,90 37,16 3,742 4,258 6,132 9,581 17,03 3,221 3,664 5,276 8,245 14,65BS2G215-1:1985 BSI 10-1999 3 Annex Methods for determining thermo-e.m.f. of conductor wires against platinum A.1 E.M.F. measurement by method o
35、f direct comparison against platinum 2)(see Figure 1) A.1.1 Sampling A sample length (approximately1m) shall be cut from the outer end of each reel or coil of the conductor. In the case of previously untested single wires, a second sample shall be cut from the inner end of each reel. The cut lengths
36、 and the reels from which they are taken shall be marked for future reference. A.1.2 Junction formation Each test sample shall be paired with a piece of platinum 2)wire of similar length. If there is insulation present,100mm shall be removed from both ends of the sample. A sound electrical junction
37、shall be formed between the pair at one end (variable temperature junction). The junction shall include all the wires of each conductor and be as short in length as possible. Its effective diameter shall not exceed the sum of the diameters of the joined conductors by more than50%. Similar junctions
38、shall be formed between the free ends of the pair and a pair of copper leads, drawn from an homogeneous source, for connection to a measuring instrument (reference junctions). A.1.3 Reference temperature Each reference junction shall be immersed in an isothermal medium, maintained at a temperature o
39、f0 0,1 C, the ultimate thermal stability of which is demonstrably unperturbed by the immersion. The depth of immersion shall be not less than80mm. A calibrated thermometer, traceable to0 C (as defined on IPTS68) within 0,1 C, shall be used to monitor the reference temperature during the test. A.1.4
40、Test temperature The variable temperature junction shall be immersed in an isothermal medium, maintained at the required test temperature, the ultimate thermal stability of which is unperturbed by the immersion. The depth of immersion shall be not less than80mm. A calibrated thermometer, traceable t
41、o appropriate points on IPTS68 to an uncertainty no greater than 0,2 C, shall be positioned in the medium so that the temperature gradient between its sensing head and the test junction is demonstrably negligible. The heat loss along the thermometer shall be insignificant. The ultimate thermal stabi
42、lity of the medium shall be not less than 0,1 C/min. A.1.5 Precautions The test arrangement shall be such that there is no electrical contact between the conductors except at the junctions and via the measuring instrument. There shall be no electrical contact between any part of the circuit and any
43、external conductor except the measuring instrument. A.1.6 Thermo-e.m.f. test When the thermometer indicates that the system has stabilized at the required temperature, the magnitude and polarity of the e.m.f. appearing between the copper leads shall be measured on a suitable instrument having an unc
44、ertainty of not more than 0,005mV. The measurement will normally entail a reversal of connections to the instrument, in which case the magnitude of the e.m.f. is decided by taking the arithmetic mean of the two readings. In determining the polarity of the e.m.f., the platinum limb shall be taken as
45、reference. The result shall be recorded against the reference number of the reel or coil. The estimated uncertainty of measurement for this method of thermo-e.m.f. determination shall be 0,02mV at all test temperatures. A.2 E.M.F. measurement by method using a substandard (see Figure 2) A.2.1 Sampli
46、ng A sample length (approximately1m) shall be cut from the outer end of each reel or coil of the conductor. In the case of previously untested single wires, a second sample shall be cut from the inner end of each reel. The cut lengths and the reels or coils from which they are taken shall be marked
47、for future reference. 2) Platinum with a temperature coefficient of resistance not greater than0,003925 3ppm.BS2G215-1:1985 4 BSI 10-1999 A.2.2 Substandard A substandard conductor, made from the same nominal material as the test sample, shall be established. The thermoelectric characteristic of the
48、substandard against platinum 3)at points on IPTS68, over the requisite temperature range, shall be known to an uncertainty no greater than 0,2 C. A certificate showing the traceability of the substandard shall be held. A.2.3 Junction formation The test sample shall be paired with a piece of substand
49、ard conductor of approximately similar length. If there is insulation present,100mm shall be removed from both ends of each conductor. Asound electrical junction shall be formed between the pair at one end (variable temperature junction). The junction shall include all the wires of each conductor and be as short in length as possible. Its effective diameter shall not exceed the sum of the diameters of the joined conductors by more than50%. Similar junctions shall be formed between the free ends of
