BS EN 03475-604:2010 pdf download

BS EN 03475-604:2010 pdf download.Aerospace series一Cables, electrical, aircraft use – T est methods Part 604: Resistance to dry arc propagation.
5 Apparatus
5.1 Electrical equipment
Connect the seven cables 01 the test sample within a circuit as shown in Figure 2. This Circuit shall have the following requirements:
a) The provision of adjustable levels of Prospective fault currents for the five A. B and C cables and an electrical return path for the two N cables.
b) A three phase 115/200 V 400 Hz (115 Vac network) or 231Y400 V 400 Hz (230 Vac network) star Ce’) connected 5Upply shall be derived from a dedicated rotary machine capable of sustaining the maximum prospective fault current given in Table 1 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 shall be s4ngle pole units rated at the values specilied in Table 2. They shall have trip characleristics in accordance with EN 2350 or as required in the product specification.
NOTE 1 Reference of circuit breakers used should be recorded.
NOTE 2 In parlicular case, others ratings of thermal breaker protection could be enloyed in accordance with awaah manufacturer rules.
d) The electrical power source shall be appropnately protected and It shall be established that no combination of test circuit events would activate this protection.
0) The ballast resistors shall be non-inductive and of appropriate power rating. Care shal 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.
f) Cables A. B and C shal be connected to indication and open circuit detectors at entry into the grounded star point. These components shall limit the standing current to no more than 10 % of the circuit breaker ating.
g) The automatic shut down facility shall provide, upon the detection of any open circuit during test and alter a lOs delay, removal of the blade from the specimen and for electrical power to be removed. Open circuit in this case means either a physical break in the specimen or a thermal breaker trip.
NOTE In the case of the automatic shut down facility is not used, the physical break I, the specimen are detected by tampa in senes with the rheostat Ag.
h) A heavy duty electrical bonding strap shall be connected between the blade of the test rig and the electrical star point 04 the generator.
i Appropnate instrumentation, recording and switching control shall be installed in accordance with good laboratory practice.
j) A rheostat Rg adjusting current (I) in the circuit to a value equal to 10% of the circuit breaker current.
5.3 Test protocol
5.3.1 The procedure emtxaces copper cable sizes 001 to 050 (26 to 10) or aluminium 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.
53.2 For the purposes of cable 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 and the blade form to be employed have been Included In this speclflcatn.
5.3.3 It is emphasized that electrical arcing tests are essentially destructive and can be hazardous to personnel. Therefore tests shall be undertaken with all observers shielded Ironi direct physical and visual exposure as noted in 5.2, I). The use 01 video recording for all tests Is required.
5.4 Test rig set-up
5.4.1 Install the rating of circuit breaker appropriate to the cable type and size to be tested (Table 2). Fit a blade to the reciprocating head of the test rig of the appropriate type shown In Figures 3 and 4.
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 adistment of resistances RI. 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 With electrical power removed adjust the test apparatus to give the correct conditions of blade stroke. frequency and downwards force. Ensure that the test fixture Is correctly positioned and that the method 01 holding the specimen provides satistaciory restraint.
5.4.4 Modify a verification sample by removing a section of cables Al and Bl ii the test zone. Adjust the blade depth stop such that the final blade position is at least half the conductoi- diameter of Al or 81, from wires AZ 82 and Cl, as shown by Figure 1.
6 Method
6.1 Test procedure
6.1.1 Install a test specimen with electncal connections as shown in Figure 1 and with RI set, as in 5.4.2 above, to give the required current Iron, Table 1.