Purpose: Two possible variants of power sources are considered: controlled three-phase bridge rectifier circuit with a step-down transformer and a pulse converter, getting power from the mains via uncontrolled three-phase bridge rectifier (Larionov circuit) for bringing into rotation with the required frequency of wheel-motor units of electric locomotives and electric trains at the position of indiscriminate diagnosis of bearings. In both cases, it is assumed that power sources receive electro-energy from a depot circuit — 380/220 V, 50 Hz. The comparison of proposed power supply options based on the assessment of energy consumption efficiency is carried out. A capacity coefficient and capacity loss in power supplies are used as measures for energy-consumption efficiency. Methods: Analytical methods are used to determine capacity losses in a transformer, controlled three–phase thyristor rectifier, uncontrolled three-phase diode rectifier, input filter of a pulse converter, IGBT transistor and reverse diode of a pulse converter. Results: Energetical indicators were determined: power losses in a transformer, a controlled three–phase thyristor rectifier, an uncontrolled three-phase diode rectifier, an input filter of a pulse converter, an IGBT transistor and a reverse diode of a pulse converter. Based on the pursued assessment of the energetical indicators of power supply two options, it is concluded on feasibility of transformer-free circuit application in bearings’ position of vibration-acoustic diagnosis. Practical importance: A variant of an energy–efficient power supply for the position of indiscriminate vibroacoustic diagnosis is proposed, which includes an uncontrolled semiconductor rectifier and a pulse converter, accomplished using an IGBT transistor.

Purpose: The conduction of experimental studies in the conditions of locomotive depot, the transition to mathematical modeling of wheel-motor block for the conditions of diagnostics position, not allowing disassembly, of traction electric motor bearings. Methods: Diagnostic complexes allowing to determine wheel-motor block technical state in locomotive depots. In order to determine the approaches for the choice and evaluation of power source parameters for vibroacoustic diagnostics position, not allowing disassembly, of wheel-motor blocks of locomotive depot the analysis of designing methodology for wheel-motor block mathematical model was carried out. Results: Inertia moment of wheelset connected to electric motor anchor is determined for the conditions of diagnostics process of bearing units of a wheel-motor block. Practical significance: Experiment in "Uzbekiston" locomotive depot of JSC "Uzbekiston Temir Yullari" to determine inertia moment of wheel-motor block and resistance to rotation moment was carried out.