ASD-STAN PREN 3475-605-2016 Aerospace series Cables electrical aircraft use Test methods Part 605 Wet short circuit test (Edition P 3).pdf

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1、ASD-STAN STANDARD NORME ASD-STAN ASD-STAN NORM prEN 3475-605 Edition P 3 June 2016 PUBLISHED BY THE AEROSPACE AND DEFENCE INDUSTRIES ASSOCIATION OF EUROPE - STANDARDIZATION Rue Montoyer 10 - 1000 Brussels - Tel. 32 2 775 8126 - Fax. 32 2 775 8131 - www.asd-stan.org ICS: 49.060 Supersedes edition P 2

2、 of June 2009 and will supersede EN 3475-605:2010 Descriptors: ENGLISH VERSION Aerospace series Cables, electrical, aircraft use Test methods Part 605: Wet short circuit test Luft- und Raumfahrt Elektrische Leitungen fr Luftfahrtverwendung Prfverfahren Teil 605: Verhalten nach Kurzschlu, feucht Srie

3、 arospatiale Cbles lectriques usage aronautique Mthodes dessais Partie 605 : Essai de court-circuit humide This “Aerospace Series“ Prestandard has been drawn up under the responsibility of ASD-STAN (The AeroSpace and Defence Industries Association of Europe - Standardization). It is published for th

4、e needs of the European Aerospace Industry. It has been technically approved by the experts of the concerned Domain following member comments. Subsequent to the publication of this Prestandard, the technical content shall not be changed to an extent that interchangeability is affected, physically or

5、 functionally, without re-identification of the standard. After examination and review by users and formal agreement of ASD-STAN, it will be submitted as a draft European Standard (prEN) to CEN (European Committee for Standardization) for formal vote and transformation to full European Standard (EN)

6、. The CEN national members have then to implement the EN at national level by giving the EN the status of a national standard and by withdrawing any national standards conflicting with the EN. ASD-STAN Technical Committee approves that: “This document is published by ASD-STAN for the needs of the Eu

7、ropean Aerospace Industry. The use of this standard is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” ASD-STAN reviews each standard and technical report at least every fi

8、ve years at which time it may be revised, reaffirmed, stabilized or cancelled. ASD-STAN invites you to send your written comments or any suggestions that may arise. All rights reserved. No parts of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any

9、 means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of ASD-STAN. Order details: E-mail: salesasd-stan.org Web address: http:/www.asd-stan.org/ Edition approved for publication 1st June 2016 Comments should be sent within six months after the date o

10、f publication to ASD-STAN Electrical Domain Copyright 2016 ASD-STAN prEN 3475-605:2016 (E) 2 Contents Page Foreword 2 1 Scope 3 2 Normative references 3 3 Specimen requirements 3 4 Preparation of specimen 3 5 Apparatus . 5 6 Method 7 7 Requirements . 8 Foreword This standard was reviewed by the Doma

11、in Technical Coordinator of ASD-STANs Electrical Domain. After inquiries and votes carried out in accordance with the rules of ASD-STAN defined in ASD-STANs General Process Manual, this standard has received approval for Publication. prEN 3475-605:2016 (E) 3 1 Scope This standard specifies a method

12、for appraising the behaviour of cable insulation subjected to an electric arc initiated and maintained by a contaminating fluid. This standard shall be used together with EN 3475-100. The primary aim of this test is: to produce, in a controlled fashion, continuous failure effects which are represent

13、ative of those which may occur in service when a typical cable bundle is damaged and subjected to aqueous fluid contamination such that electrical arcing occurs, between cables, and to examine the aptitude of the insulation to track, to propagate electric arc to the electrical origin. Originally def

14、ined for 115 Vac network, this test also proposes conditions for 230 Vac network. Unless otherwise specified in product standard, only 115 Vac conditions shall be satisfied. Six levels of prospective fault current have been specified for concerned cable sizes (see Clause 7). It is generally agreed t

15、hat larger sizes need not be assessed since the short-circuit phenomenon becomes dominant at low line impedances. Unless otherwise specified in the technical/product standard sizes 002, 006 and 020 cable shall be assessed. 2 Normative references The following documents, in whole or in part, are norm

16、atively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 2350, Aerospace series Circuit breakers Technical specific

17、ation EN 3197, Aerospace series Design and installation of aircraft electrical and optical interconnection systems EN 3475-100, Aerospace series Cables, electrical, aircraft use Test methods Part 100: General A-A-52083, Tape, lacing and tying, glass 1) 3 Specimen requirements Cables to be tested sha

18、ll be of traceable origin and shall have passed the high voltage dielectric test defined in the product standard. 4 Preparation of specimen 4.1 Cut seven separate lengths of approximately 0,5 m consecutively from one length of cable, and strip one of the ends of insulation to permit electrical conne

19、ction. Clean each length of cable with a clean cloth moistened with propan-2-ol (isopropyl alcohol) fluid. 1) Published by: Department of Defense Industrial Supply Center, ATTN: DISC-BBEE, 700 Robbins Avenue, Philadelphia, PA 19111-5096 USA. prEN 3475-605:2016 (E) 4 4.2 Lay up the seven cables as fo

20、llows: a) Form the cables in a six around one configuration as shown in Figure 1. b) Ensure that all cables are straight and geometrically parallel, and restrained by lacing tapes such that they are in continuous contact at least within the test zone. c) Position the lacing tapes at 50 mm spacing to

21、ward the end of the specimen as shown in Figure 2. The first lacing tapes shall be at no more than 5 mm behind the dripping point. The tie material shall be PTFE glass lacing tape conforming to A-A-52083 type IV, finish D, size 3. d) Number the cables as shown in Figure 1 such that the cables in dir

22、ect contact with the drops are numbers A1 and B1 and the centre is N. Cables C1, A2, B2 and C2 are grouped around N. Key 1 Drop needle A1-A2 : Phase A B1-B2 : Phase B C1-C2 : Phase C N : Neutral cable connected to earth Figure 1 Specimen configuration prEN 3475-605:2016 (E) 5 Key 1 Lancing tape 2 Dr

23、op needle 3 Drops 4 10 mm to 20 mm 5 Ends of the 7 cables in the same plane Figure 2 Test configuration 5 Apparatus 5.1 Electrical equipment Connect the seven cables of the test sample within a circuit as shown in Figure 3. This circuit shall have the following requirements: a) The provision of adju

24、stable levels of prospective fault currents for the six A, B and C cables. b) A three phase 115/200 V 400 Hz (115 Vac network) or 230/400 V 400 Hz (230 Vac network) star (Y) connected supply shall be derived from a dedicated rotary machine capable of sustaining the maximum prospective fault current

25、given in Table 1 (115 Vac network) or Table 2 (230 Vac network) for at least sufficient time for circuit protection to operate. In any case the generator shall have a sufficient rating to provide these prospective fault currents. c) 115 Vac or 230 Vac circuit breakers (D2) shall be single pole units

26、 rated at the values specified in Table 3. They shall have trip characteristics in accordance with EN 2350 or as required in the product specification. NOTE 1 Reference of circuit breakers used shall be recorded. NOTE 2 In particular case, others ratings of thermal breaker protection could be employ

27、ed in accordance with aircraft manufacturer rules. d) The electrical power source shall be appropriately protected and it shall be established that no combination of test circuit events would activate this protection. e) The ballast Rb resistors shall be non-inductive and of appropriate power rating

28、. Care shall be taken to position all laboratory wiring such that inductive effects are reduced to a practical minimum. Supply cables shall be as short as possible. prEN 3475-605:2016 (E) 6 The ballast resistor Rb is in order to prevent over voltage (115 - 115 W per phase for 115 Vac network or 230

29、- 230 W per phase for 230 Vac network) during the arc extinction phases (opening of an inductive circuit). f) A rheostat, Rf, limiting maximum short-circuit current per phase by simulating a line length. g) Appropriate instrumentation, recording and switching control shall be installed in accordance

30、 with good laboratory practice. Key 1 Supply protection 2 Test bundle Figure 3 Test schematic circuit 5.2 Test equipment Construct an apparatus as shown diagrammatically in Figure 2, which includes the following minimum provisions: a) Electrical terminations to provide a ready means of connecting te

31、st specimens into the circuit as shown in Figure 3. b) A transparent enclosure to protect personnel from ejected molten metal and short wavelength ultra violet light. c) An electrolyte delivery system which provides a constant rate of (100 10) mg/min and dispenses drops from an 18 gauge needle, cut

32、of square at the outlet. NOTE The needle wall thickness shall be selected such that the specified flow rate shall be delivered at approximately 6 drops per minute. prEN 3475-605:2016 (E) 7 5.3 Test protocol 5.3.1 The procedure embraces copper cable sizes 001 to 051 (26 to 10) or copper clad aluminiu

33、m cable sizes 002 to 090 (24 to 8), and for each cable size six values of prospective fault current have been defined. Performance of a cable size at a given fault intensity shall be determined by testing three samples. Thus 18 samples are required for every cable size. 5.3.2 For the purposes of cab

34、le qualification at least sizes 002, 006 and 020 shall be tested. Additional testing of other sizes may be deemed necessary in particular cases and values of prospective fault currents, the ratings of thermal breaker protection which are typical of aircraft use have been included in this specificati

35、on. 5.3.3 It is emphasised that electrical arcing tests are essentially destructive and can be hazardous to personnel. Therefore tests shall be undertaken with all observers shielded from direct physical and visual exposure as noted in 5.2 b). The use of video recording for all tests is required. 5.

36、4 Test rig set-up 5.4.1 Install the rating of circuit breaker appropriate to the cable type and size to be tested (Table 3). 5.4.2 Heavy duty electrical shorting connections shall be fitted in substitution of a test sample to enable prospective fault currents to be set by adjustment of resistances R

37、f. Because these currents would trip the thermal breakers very rapidly these shall be shunted to permit the pulsing of current until the desired value is obtained. Re-instate the thermal protection. 5.4.3 Prepare an electrolyte solution made by dissolving 3 % 0,5 % by weight of sodium chloride in di

38、stilled water. 5.4.4 Support the specimen in free air inclined at an angle of 10 to the horizontal with the electrical input connections at the higher end. 5.4.5 Position the delivery system so that the electrolyte contacts the loom from a height of (10 2) mm above the uppermost cables in the loom a

39、t a point which shall position the droplets into the upper cut or no more than 2 mm towards the higher end of the specimen. Ensure that the drops strike the cables at the top centre of the circumference such that they fall into the crevice between cables A1 and B1. 6 Method 6.1 Test procedure 6.1.1

40、Install a test specimen with electrical connections as shown in Figure 1 and with Rf set, as in 5.4.2 above, to give the required current from Table 1 or Table 2. 6.1.2 Apply electrical power to the specimen and start the flow of electrolyte at a rate of (100 10) mg/min. Particular care shall be tak

41、en to ensure that the electrolyte flows between the damage sites as evidenced by steaming of the electrolyte and the development of scintillation. Shall this not occur, and failure of the cable to wet be determined, then the alternative surfactant described in 5.4.3 may be used. 6.1.3 Run the test c

42、ontinuously for a period of 2 h. If the circuit-breaker(s) of phases A1, A2, B1, B2, C1 and C2 do not trip for a duration of 2 h, switch off the power supply and the electrolyte flow. Stop the test. prEN 3475-605:2016 (E) 8 6.1.4 Following CB(s) tripping adopt the following procedure: a) After not l

43、ess than 3 min, nor more than 10 min, and with all thermal circuit breakers closed, reapply power to the specimen with no further flow of electrolyte. b) Apply power for the time necessary for any fault condition to develop fully but do not reset the thermal circuit breakers. 6.1.5 Repeat the test t

44、o obtain three samples and then reset the circuit for the next highest current overload until all 18 samples have been tested. 6.2 Examination EN 3197, can be used as a guideline to differentiate short-circuit and arc-tracking effects. Noticeable damages may come from either: Aptitude of the insulat

45、ion to become an electrically conducting material (arc-tracking phenomenon), Propagation of thermal effects due to established arcs, Duration of the test causing electro-erosion, As result of thermal effects due to possible short-circuit. a) Carefully remove the test specimen from the apparatus and

46、photograph the cable bundle. b) Examine visually and record the damage to the insulation including the length of char. Also record if there is evidence of tracking effect to the electrical source. 6.3 Test report The test report shall include details of the following: a) Clearly mentioned which type

47、 of tension was tested (115 Vac or 230 Vac). b) Identity of the cable type and size and details of the origin and release certification permitting traceability to a production batch. c) Identity of circuit breakers used. d) Characteristics of the power source. e) Operation of individual circuit brea

48、kers. f) Record of the damage as required in 6.2.2. 7 Requirements The detail product specification shall define: tension to test if different from 115 Vac, the pass/fail criteria for each cable size, in any series of tests. In any case the cable shall not present evidence of tracking effect longer

49、than the value mentioned in the related product specification. prEN 3475-605:2016 (E) 9 Table 1 Prospective fault currents for 115 Vac network Type of cables Size code AWG a Prospective fault currents (Amps) Copper conductors 001/002 26/24 8 15 25 40 60 80 004/006 22/20 20 30 45 60 80 160 010 to 051 18 to 10 40 60 80 100 125 250 Copper clad aluminium conductors 002/004 24/22 8 15 25 40 60 80 006/010 20/18 20 30 45 60 80 160 012/090 16 to 8 40 60