1、ASD STANDARD NORME ASD ASD NORM prEN 3475-802 Edition P 2 July 2007 PUBLISHED BY THE AEROSPACE AND DEFENCE INDUSTRIES ASSOCIATION OF EUROPE - STANDARDIZATION Avenue de Tervuren, 270 - B-1150 Brussels - Tel. + 32 2 775 8126 - Fax. + 32 2 763 3565 - www.asd-stan.orgICS: 49.060 Supersedes edition P 1 o
2、f May 1997 and will supersede EN 3475-802:2002 Descriptors: ENGLISH VERSION Aerospace series Cables, electrical, aircraft use Test methods Part 802: Capacitance unbalance Srie arospatiale Cbles lectriques usage aronautique Mthodes dessais Partie 802 : Dsquilibre de capacit Luft- und Raumfahrt Elektr
3、ische Leitungen fr Luftfahrtverwendung Prfverfahren Teil 802: Kapazittsdifferenz 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 the needs of the European Ae
4、rospace 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 functionally, without re-
5、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). The CEN national members
6、 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. Edition approved for publication 31 July 2007 Comments should be sent within six months after the date of publication to ASD-STAN Ele
7、ctrical Domain Copyright 2007 by ASD-STAN prEN 3475-802:20072 Contents Page Foreword2 1 Scope 3 2 Normative references 3 3 Preparation of specimens.3 4 Apparatus .3 5 Method 3 6 Requirement.5 Foreword This standard was reviewed by the Domain Technical Coordinator of ASD-STANs Electrical Domain. Afte
8、r 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 3475-802:20073 1 Scope This standard specifies a method for measuring the capacitance unbalance for digital data transmiss
9、ion cable (within a pair or quad). It shall be used together with EN 3475-100. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the ref
10、erenced document (including any amendments) applies. EN 3475-100, Aerospace series Cables, electrical, aircraft use Test methods Part 100: General. EN 3475-801, Aerospace series Cables, electrical, aircraft use Test methods Part 801: Capacitance per unit length. 3 Preparation of specimens These shal
11、l be stripped and prepared for connection to the measuring device. 4 Apparatus The capacitance shall be measure with an unbalance bridge at a frequency of (1 000 100) Hz. Various types of automatic or semiautomatic equipment may also be used. 5 Method 5.1 Screened pair capacitance unbalance Capacita
12、nce shall be measured as indicated in EN 3475-801. The length of the sample shall be 3 m or more. Capacitance unbalance as a percentage shall be determined from the following formula: cbabac) (2) (4100CCCCCD+= 5.2 Screened quad capacitance unbalance pair to pair Pair to pair capacitance unbalance is
13、 illustrated in Figure 1, where 1 and 2 represent the two conductors of a pair and 3 and 4 represent the two conductors of another pair. The length of the sample shall be at least 100 m or more. Capacitance unbalance pair to pair per unit of length shall be determined from the following formula: Cpp
14、 = C13+ C24 C23 C14prEN 3475-802:20074 Used the following formula if measured length is other than 100 meters: /100LcCppCpp= where Cpp is the unbalance in picofarads corrected to 100 meters; Cpp is the unbalance of cable length (m); Lc is the cable length (m). Figure 1 5.3 Screened quad capacitance
15、unbalance pair to ground Pair to ground capacitance unbalance is illustrated in Figure 2, where 1 and 2 represent the two conductors of a pair and 3 and 4 represent the two conductors of another pair. (In case of multi pair cable, all other pairs in cable shall be connected together and grounded). T
16、he length of the sample shall be at least 100 m or more. Capacitance unbalance pair to ground per unit of length shall be determined from the following formula: Cpg = C10 C20Used the following formula if measured length is other than 100 meters: )/100(LcCpgCpg= where Cpg is the unbalance in picofarads corrected to 100 meters; Cpg is the unbalance of cable length (m); Lc is the cable length (m). C24C23C14213 4C13prEN 3475-802:20075 Figure 2 6 Requirement The value obtained shall not exceed the values specified in the product standard. 3412C10C20
