Measurements of armature current in the brush collector unit of a direct current motor during the commutation period

Abstract

The operating conditions of locomotives determine the special technical state requirements of individual units and aggregates. Traction dc motors are the most heavily loaded and vulnerable objects as far as the work of commutators and their influence on the commutation processes in a motor are concerned. Analysis of the effects of a brush collector unit shows that the split-type-brush-based method for finding the technical state of a dc machine is not sufficiently informative about the commutation process. The current measurement of a short-circuited section of the armature winding during the commutation period was made using two parts of a split-type brush and a proper measurement scheme was proposed. A test bench for the research of the commutation processes in a dc motor was designed, which provided the description of the transition processes in a commutator of a dc machine at the use of a brush consisting of two parts. The current distribution in a short circuited coil and separate parts of a brush was obtained. The measurement scheme of the armature current at a commutator is presented and the experimental results are provided in the form of oscillograms of the characteristics of a real motor.