Post-repair testing of the walking excavators’ electrical machines

Abstract

Dragline excavators are the main means of mechanization in mining coal fields. The operational reliability and in-use performance of the overburden dragline excavators determine the mining enterprises’ capacity. The aim of the study is to increase the reliability of the excavators’ electromechanical equipment. The main research method is modeling of the electromagnetic processes taking place in the after-repair tests of the excavator’s electric machines. The study has shown that the failures of the mining equipment operating in the northern part of Russia are of both mechanical and electromechanical nature. The failures associated with electromechanical emergency conditions are more often caused by the failure of the direct-current electric machines of the excavators’ main drives. To ensure the high quality of the repair and reduce the risk of failure, all electrical machines must undergo appropriate post-repair tests including those under load. The existing loading methods involve mechanical aggregation of the electric machine with the load devices. It is difficult to implement these methods when testing large direct-current electric machines in the conditions of the repair plants. Obviously, the development of the test methods that exclude mechanical aggregation of the electric machines and load devices is important and promising. Static loading of electrical machines is proposed as one of the above methods. The method implies dividing the test in two stages. In the first stage, static current loading is performed, and in the second stage, dynamic current and mechanical loading are carried out in the modes close to operational ones. The study of the control system developed for the electric drive of the test stand has shown that the system is functional and allows the testing of the direct-current electric machines in full.