Evaluation of the influence of the cooling system of an electric locomotive and the parameters of train movement on cracking in the frame of the NB-514 traction motor

Abstract

The purpose of this work is to identify the causes of cracks in the frames of traction electric motors of modern domestic electric locomotives. An analysis of the statistics of detection of cracks in the frames of NB-514 traction motors at the Eastern range is given, showing that almost every third frame of this traction motor in operation has cracks, while the main share of the identified cracks falls on electric locomotives of the 2,3,4ES5K series. The results of mathematical modeling of mechanical stresses arising in the frame of the NB-514 traction motor during its uneven heating to temperatures typical for the hourly operation of the traction motor are considered. It was revealed that mechanical stresses arising only from the temperature difference between the ambient air and the windings of the main and additional poles of the traction motor can reach mechanical stresses over 100 MPa, which exceeds the endurance limit of the frame steel. Mathematical calculations of the arising mechanical stresses in the frame of the traction electric motor are performed depending on its heating during operation at the mountain pass section Bolshoy Lug – Slyudyanka of the East Siberian Railway – a branch of Russian Railways. It is concluded that one of the main causes of cracking in the frames of traction motors is the presence of thermal stresses caused by low-cycle fatigue due to engine heating with a decrease in air consumption for cooling the traction motor. To reduce cracking in the frame of the NB-514 traction motor, it is proposed either to increase the air flow by the ventilation system, or to change the shape of the ventilation and viewing windows of the frame of this traction motor.