BS EN 50592:2016 pdf download – Railway applications — Testing of rolling stock for electromagnetic compatibility with axle counters
4 Measurement specification for vehicle emissions
4.1 Rolling stock emission limits In the scope of interoperability, limits are defined in the TSI Interface document ERA/ERTMS/033281. Outside interoperability, individual limits are defined in CLC/TS 50238-3 or in NNTRs where these exist. In specific application cases outside the scope of Interoperability Regulations, limit values may be notified by the axle counter manufacturer, according to the process, defined in EN 50617-2. The RST under test shall be defined in the context of the definition for an influencing unit. The influencing unit shall be defined in an EMC Management Plan, depending on the sources of magnetic fields.
4.2 Methodology for the demonstration of vehicle compatibility
4.2.1 General approach Measurements shall be performed using specified measurement antennas described in 4.2.2, under specified operational conditions of rolling stock. Compatibility tests of vehicles can be executed with any rail type. The influence of the type of rail on the measurement result is accounted for in the compatibility limits and the associated margin. The train shall be tested under the electrification system(s) for which it is to be authorized. The methodology is also applicable to other type vehicles, as explained in Emissions caused by vehicles are measured as magnetic fields in X, Y and Z directions. Ambient noise measurements shall be conducted before the tests. If at specific frequencies or in specific frequency ranges the ambient noise is higher than the limit values less 6 dB, the measurements at these frequencies need not be considered provided there is clear evidence that the emissions are attributable to ambient sources. These frequencies shall be noted in the test report. If the ambient noise within the frequency bands in ERA/ERTMS/033281 or the individual limits in CLC/TS 50238-3 is so severe (e.g. wide band noise) that it makes the assessment of the vehicle to the frequency bands impossible, a new test at an alternative test location is required, which is not influenced by the identified ambient disturbance. The RST is normally tested under conditions at which maximum emissions are expected in the frequency range considered for compatibility. Specific requirements are derived in NOTE Usually, it is possible to capture these emissions at low vehicle speeds. The repetition rate of the interference is partly independent of the vehicle speed (e.g. rolling stock with four-quadrant traction and auxiliary converters) and for rolling stock with motor inverters it is even lower at higher speeds.
4.2.2 Measurement antenna Frequency range The measurement chain shall cover the 10 kHz to 1,3 MHz range between the 3 dB points. Due to the fact that the range of operating frequencies of the axle counter detectors used in Europe is from tens of kilohertz up to 1,3 MHz, it may not be possible to achieve an acceptably low measurement uncertainty with only one measurement antenna, to cover both the lower and the higher frequency range. The frequency range applicable to each antenna, shall be specified:
• Lower Frequency Range (LFR): 10 kHz to 100 kHz;
• Higher Frequency Range (HFR): 100 kHz to 1,3 MHz. Electrical surface A rectangular 3-dimensional magnetic loop antenna with a common centre point and the following geometrical dimensions shall be used:
• 5 cm x 5 cm (25 cm 2 ) (loop for measurement of field along x-axis), named X-coil;
• 5 cm x 15 cm (75 cm 2 ) (loops for measurement of field along Y- and Z- axis), named Y and Z coils. The longest arm is always in X-direction. Depending on the size of the wire and the number of windings, small deviations from the ideal shape of the transducer are permitted but such deviation shall not exceed 5 %. As far as possible, the electrical surface and the ratio shall be kept. NOTE 1 The arm length of 15 cm is chosen such that it represents a practical optimum between the averaging of gradient magnetic fields and the picking up of interference source with low repetition rates.