THE STUDY OF MAGNETIC FIELDS AT THE WORKING PLACES OF MUNICIPAL TRANSPORT VEHICLES AND METHODS OF THEIR ATTENUATION

Abstract

The subject of the presented work is the study of magnetic fields at the workplaces of rolling stock of municipal electric transport. The purpose of the work is the experimental study of the actual levels of magnetic fields at the workplaces of rolling stock of urban electric transport and the development of measures for their normalization. For research purposes, the most common samples of urban electric transport in Kyiv have been chosen - trolleybus, tram and underground. For carrying out of researches the assistant meter of a stationary magnetic field MTM-01 was used. Given the change in power of the electric drive, measurements were made at different modes of movement of vehicles at the workplace drivers. Based on the analysis of the obtained data it is determined that the value of the induction of the stationary magnetic field at the workplaces of trolley bus drivers is approximately twice lower than the values of the geomagnetic field and practically does not depend on the modes of motion. In the rolling stock of the subway, the value of the magnetic field induction is practically continuous in different motion modes and exceeds the value of the natural field. In this case, during acceleration and inhibition modes, there is a significant increase in the level of the field with its inversion. The most complicated pattern is the dynamics of magnetic field induction in the tram. At the stop it is lower than the natural value, when driving at constant speed the induction increases almost to the natural value, and during acceleration and inhibition there is a sharp increase (up to triple of the natural). At the same time there is an unpredictable inversion of the dominant magnetic field direction. It is proved that significant fluctuations in the magnetic field induction require the development of organizational and technical measures to reduce the amplitude of field fluctuations. It is shown that the use of a special screen made of magnetically soft sheet material, reduces the amplitude of field fluctuations and approximates its value to the level of the natural geomagnetic field. But the choice of the most rational location is crucial for efficient application of such screen under real conditions.