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  • 5 Test methods 5.1 Introductory remarks Different methods of carrying out the VE test can be used. The differences concern the way of applying voltage (constant or increasing with time), the frequency (service or higher) and the time at which the test is interrupted (the time to dielectric breakdown for all sample specimens (complete life tests) or a shorter time for some of the specimens of the sample (censored life tests). In general to enable comparisons to be made, the type of ageing cell or test object shall be the same, whatever the choice of the parameters above. However, with...
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  • 6.3.7 Alien (exogenous) near-end crosstalk Generally proven by design. 6.3.8 Alien (exogenous) far-end crosstalk Generally proven by design. 6.3.9 Alien (exogenous) crosstalk of bundled cables The minimum requirement is not specified but it should be stated in the relevant detail specification. 6.3.10 Impedance The mean characteristic impedance shall be within ±5 % of the requested nominal impedance at 1 00 MHz. 6.3.11 Return loss (RL) The minimum return loss of any pair in the frequency 1 MHz to 1 200 MHz shall be equal to or greater than the values obtained from Table 4. 6.4.11 Repeated bending of the cable...
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  • 4.3.2 Colour of insulation There is no preferred colour for the insulation. The colour of the insulation shall be achieved by the use of coloured compounds or other suitable method. The insulation, whether coloured or not, may be transparent. 4.3.3 Application to the conductor The insulation shall be closely applied to the conductor or separator. It shall be possible to remove the insulation without damage to the insulation itself, to the conductor, or to the tin coating if any. Compliance shall be checked by inspection and by manual test. 4.3.4 Thickness The mean value of the thickness of the insulation...
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  • With regard to the variety of equipment and environmental conditions to be considered, it is difficult to indicate exact rules concerning the selection of tests. This selection is primarily the responsibility of the product committee concerned (based on their experience). In special cases, this can be fixed by agreement between the manufacturer and the user. In all cases, knowledge of the electromagnetic environment (the IEC 61000-2 series, especially IEC 61000-2-5) and awareness of the statistical aspects explained in IEC 61000-1-1 will be helpful. Test according to IEC 61 000-4-2 (Electrostatic discharge immunity test) In general, the electrostatic discharge test is...
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  • During operation, the capacitors are subjected to the supply mains voltage with a superimposed radio interference voltage. In many cases, the extra load caused by the radio- frequency voltage is not important, but in other cases an appreciable radio-frequency current through the capacitor may occur or high voltage peaks may be present. This must be taken into account when choosing the capacitor and a check should be made with the capacitor under its working conditions to make sure that its ratings are not exceeded. The presence of inductance in the supply circuits in series with the capacitor may cause the...
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  • 4 General requirements 4.1 General characteristics Criticality alarm systems are designed for the automatic and prompt detection of gamma radiation or neutrons from a criticality accident and to actuate immediate evacuation and warning alarms. The primary functions of the criticality alarm system shall be to: – detect a criticality accident as soon as it occurs within the monitoring zone of the detector(s); – actuate an alarm with minimal delay; – achieve a high degree of reliability required by its safety classification and low probability of false alarm; – fail safe by design and reveal failures (single failure shall be indicated...
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  • The characteristics of the generic voltages of traction power supply systems (overvoltages excluded) are specified in Table 1 below. “Generic”, means that these voltages of the traction power supply systems are to be used in projects which have common/classical operating parameters and allow the use of other generic international standards. These traction power supply systems are implemented in many countries over the world and their efficiency is proven. 4.2 Frequency The frequency of the 50 Hz and 60 Hz electric traction systems is imposed by the three phase grid. NOTE 1 Therefore, the values stated in EN 501 60 are...
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  • 3.1 3 suppl y vol tage dip sudden reduction of the supply voltage to a value of less than U mi n2 , followed by a voltage recovery after a short period of time . Conventionally , the duration of a voltage dip is between 1 0 ms and 1 min . The depth of a voltage dip is defined as the difference between the minimum r.m.s. voltage during the voltage dip and the nominal voltage U n . Voltage changes which do not reduce the supply voltage to less than U mi n2 are not considered to be dips...
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  • 4 Properties 4.1 General properties As defined in 3.2, silicone liquid for transformers has high flash and fire points and is therefore difficult to ignite. If combustion occurs, heat release rate is much lower than that of hydrocarbon oils. In addition to use at similar working temperatures to those of transformers containing mineral transformer oil, silicone insulating liquids may also be used in appropriately designed electrotechnical equipment operating at higher temperatures. The solubility of water in silicone liquids is greater than in mineral oils. Other physical characteristics which are important for the design of electrotechnical equipment, e.g. heat transfer, may...
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  • 5 Requirement for marking The product shall be marked by printing, embossing or indenting on the sheath or on a label attached to the product or on a component inside the cable. NOTE 1 Embossing is not recommended on the insulation. A label shall be attached to the product in a permanent way and be clearly detectable to the electrical installer. NOTE 2 The label should preferably be attached to that part of the product which is clearly visible when unpacking the product, ready for installation. The marking shall at least contain: • identification of the manufacturer by name and...
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