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The practice of operating machinery and equipment that are used in animal husbandry and in the processing of its products has shown low reliability of feed crushers. As of 01.01.2019, in the agricultural enterprises of the Republic of Tatarstan there are about 1200 machines for grinding feed, of which 800 pcs. are hammer crushers. Most of these crushers have a service life of 10 to 13 years and are objects with low reliability. Mostly emergency stops occur due to the destruction of the rotor bearings. In the event of a sudden failure, unplanned repairs and a decrease in production efficiency occur. At the Department of Operation and Repair of Machines of Kazan State Agrarian University, research was carried out and a scientific result was obtained, which was implemented in the adapter to the vibrometer to determine the residual life of rolling bearings. Input data for this device were obtained during operational research and further analysis of the data.

The aim of the paper is theoretical and experimental research of processes during the single-phase ground faults in electrical distribution grids of 10/06/35 kV with isolated neutral mode. The mathematical method of rationing is used for the analysis of the spectral composition of currents and voltages increasing the information content of the allocated higher harmonics of current and voltage. The paper show a comparison of the results of spectral analysis with and without taking into account the mathematical rationing obtained on the simulation model. Field experiments have demonstrated the effectiveness of using of the method of mathematical rationing of the higher harmonic components of current and voltage for various types of single-phase ground faults. The results of field experiments provided an opportunity of improving the methodology of yearling detection of single-phase ground faults in electric grids of 6-10-35 kV with an isolated mode of neutral. The conclusion of the research is the possibility of a significantly more accurate selection of the resonant frequencies of the spectrum of currents and voltages obtained by using of the method of mathematical rationing. The possibility of earlier and more precise localization of the feeder with ground fault is shown on the base more precise selection of the resonant frequency currents and voltages.