1、STDOAECMA PREN 3841-304-ENGL 1998 LOL2311 OOL489L 198 Edition approved for publication AECMA STANDARD prEN 3841 -304 NORME AECMA Edition P 2 AECMA NORM 1.l. J September 1998 PUBLISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE INDUSTRIES (AECMA) Gulledelle 94 - 8-1200 BRUXELLES - Tel. +32) 2 775 81 10
2、 - Fax. (+32) 2 775 81 li ICs: 49.060 Descriptors: Supersedes edition P 1 June 1996 C2 Chairman Comments should be sent within six months after the date of publication to ENGLISH VERSION Aerospace series Circuit breakers Test methods Part 304: Tripping points Srie arospatiale Disjoncteurs Mthodes de
3、ssais Partie 304: Limites de dclenchement Luft- und Raumfahrt Schutzschalter Prfverfahren Teil 304: Auslsegrenzen This “Aerospace Series“ Prestandard has been drawn up under the responsibility of AECMA (The European Association of Aerospace Industries). It is published on green paper for the needs o
4、f AECMA-Members. It has been technically approved by the experts of the concerned Technical Committee following comment by the Member countries. Subsequent to the publication of this Prestandard, the technical content shall not be changed to an extent that interchangeability is affected, physically
5、or functionally, without re-identification of the standard. After examination and signature of the AECMA Standard Checking Centre (NPS) and formal agreement of the Official Services of the Member countries it will be submitted as a draft European Standard to CEN (European Committee for Standardizati
6、on) for formal vote. 1998-09-30 AECMA Gulledelle 94 B-1200 BRUXELLES Mr Pezzetta aecma 1998 STD-AECMA PREN 3841-304-ENGL 1998 103233L 0034892 024 Page 3 prEN 3841 -304: 1998 1 Scope This standard specifies a method of verifying the tripping points of circuit breakers. It shall be used together with
7、EN 3841-100. 2 Normative references This European Standard incorporates by dated or undated reference provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments
8、to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 3841-100 Aerospace series - Circuit breakers - Test methods - Part 100: General 1)
9、3 Method 3.1 General conditions The circuit breakers shall be mounted as described in clause 4 of EN 3841-100, in connection with the applicable technical specification. During the test, the current applied to the circuit breakers shall remain constant. The current may be either d.c. or a.c. with fr
10、equency indicated in the product standard and resistive load. Prior to each test, the tripped circuit breakers (with main contacts open) and their connections shall be stabilized to the specified temperature f 5 OC. The test shall only be carried out at normal airflow. 3.2 Tripping points 3.2.1 Mini
11、mum tripping point The circuit breakers shall be subjected to the current specified in the product standard. The minimum tripping time shall be in accordance with the product standard. The circuit breakers shall not trip during this period. The temperature of the terminals shall be measured througho
12、ut the test. The temperature increase of the terminals shall not exceed 75 K. For this measurement, thermocouples or other appropriate low conductivity sensors shall be used, placed on a terminal as close as possible to the housing of the circuit breaker. 3.2.2 Maximum tripping point When subjected
13、to the current specified for the maximum tripping point in the product standard, the circuit breakers shall trip within the specified time. 3.2.3 Overload tripping The circuit breakers shall be subjected to the currents specified in the product standard and the tripping time shall be measured. 1) Pu
14、blished as AECMA Prestandard at the date of publication of this standard Previous page is blank STDmAECMA PREN 3843-304-ENGL 3998 m 3032333 0034893 TbO m Page 4 prEN 3841 -304: 1998 3.2.4 Trip free release Overload tripping with the actuator button held in the closed position shall be verified in ac
15、cordance with the conditions specified in the technical specification. 3.2.5 The circuit breakers shall be placed in a suitable low pressure/temperature chamber and shall be connected to the applicable current source. The chamber shall be set to the test temperature indicated in the product standard
16、 held constant for a minimum of 1 h. Then the chamber shall be brought to the atmospheric pressure corresponding to the altitude specified in the product standard. Under these conditions, the circuit breakers shall be subjected to the current defined in the product standard for the minimum points at altitude and temperature. The test period shall be 1 h. Minimum tripping points at altitude 3.3 Requirements The tripping points and trip times shall meet the requirements of the product standard.
