Об оценке коммутационной способности тяговых двигателей грузовых электровозов

Abstract

An important direction in the development of JSC Railways is increasing the volume of freight traffic over the railway network. A number of measures are being taken to achieve the predicted strategic indicators in the locomotive complex. The most large-scale activities include research and experimental works aimed at improving the traction properties of electric locomotives in the Eastern polygon, which is one of the most heavily loaded sections of the Russian railway network. This is an important link connecting Southeast Asia and Europe. The conditions under which the railway transport operates require, among the priority tasks, efficient use of the locomotive fleet with high operational reliability to ensure safe train traffic. The Eastern polygon uses a system of electric traction powered by the 25 kV, 50 Hz AC voltage. Freight trains are driven by 2ES5K and 3ES5K electric locomotives equipped with pulsating current commutator traction machines. In implementing the required traction forces, the traction electric drive of such locomotives has a number of limitations. One of them is the quality of switching on the traction motor commutator. Achieving better reliability of traction motors, which are regarded as the weak link of electric locomotives, is a topical problem. The number of their failures due to faults of direct and pulsating current traction motors is at the level of 20--22%. The greatest difficulty is to increase the switching reliability. A switching quality criterion for traction electric motors of electric locomotives is proposed, which takes into account the degree to which the armature reaction magnetomotive force is compensated in the switching zone. The width of the sparkless operation region cannot fully characterize the traction electric motor switching capacity. Its calculation takes into account the spark voltage under the brush, the effect of electromagnetic factors on the switching, the design of additional poles, and the kind of load current. The accomplished calculations have shown that the proposed switching reliability quality criterion objectively characterizes the switching quality in the limiting mode and is consistent with the long-term experience of their operation in AC electric locomotives.