Study of the characteristics of external noise of dual-powered electric locomotive

Abstract

The article presents the results of tests of a freight dual-system electric locomotive 2EV120 when operating in stationary mode and moving at normalized speed. In the course of conducting experimental studies of the sound level of external noise during operation of a locomotive at a constant and alternating current, exceeding the regulatory requirements at individual observation points was found, and it was noticed that the operation of the traction transformer is the main source of increased noise, the main component of which is air in this case. It has been established that in the sound field formed around an electric locomotive operating in the parking lot, the distribution of sound levels is uneven. An example, given in the article, describes the distribution of sound levels when an electric locomotive is operated on alternating current before and after the application of noise protection measures. In the process of testing, a set of organizational and technical measures was developed, the implementation of which reduced the external noise of the electric locomotive 2EV120 as a whole to the regulatory requirements. In particular, to reduce the noise from the operation of the traction transformer, as one of the options, it is proposed to install a shielding device in its sub-body part, the minimum efficiency of which was 4.2 dBA. Analysis of the regulatory margin for external noise showed that its value at the observation point located opposite one of the operating traction transformers equipped with a shielding device is minimal. One of the reasons for this in this case is the sound energy penetrating through the body covering of a large area, generated by the work of the locomotive's internal equipment. In order to increase the regulatory margin when the 2EV120 electric locomotive is operating at a constant current, the authors propose the following: to strengthen the sound insulation capacity of the thin-walled body plating of the electric locomotive by installing a double-wall sound-insulating structure with sound-absorbing material inside it.