Nowadays detection of deterioration of electrical motors is an important topic of research. Vibration signals often carry diagnostic information of a motor. The authors proposed a setup for the analysis of vibration signals of three-phase induction motors. In this paper rotor fault diagnostic techniques of a three-phase induction motor (TPIM) were presented. The presented techniques used vibration signals and signal processing methods. The authors analyzed the recognition rate of vibration signal readings for 3 states of the TPIM: healthy TPIM, TPIM with 1 broken bar, and TPIM with 2 broken bars. In this paper the authors described a method of the feature extraction of vibration signals Method of Selection of Amplitudes of Frequencies – MSAF-12. Feature vectors were obtained using FFT, MSAF-12, and mean of vector sum. Three methods of classification were used: Nearest Neighbor (NN), Linear Discriminant Analysis (LDA), and Linear Support Vector Machine (LSVM). The obtained results of analyzed classifiers were in the range of 97.61 % – 100 %.

Spontaneous combustion of sulfide ore is one of the most common disasters in the process of ore mining, storage, and transportation, which can lead to a series of safety and environmental problems, thus affecting sustainable development in society. In this paper, four imidazolium-based ionic liquids: [BMIM][I], [BMIM][BF₄], [EMIM][BF₄], and [BMIM][NO₃], were selected for inhibition experiments with sulfide ores to reveal the inhibition performance of ionic liquids against spontaneous combustion. The results show that the main products from the reaction were Fe₂O₃ and SO₂, produced during the process of oxidation and spontaneous combustion and that the reaction moves towards a higher temperature under the action of ionic liquid, indicating that ionic liquids have a significant inhibition effect on the spontaneous combustion of sulfide ore. At the same temperature, the apparent activation energies of the samples treated with ionic liquids were all greater than those of the control samples, indicating that imidazolium-based ionic liquids can effectively reduce the spontaneous combustion tendency of sulfide ores. In addition, compared with other ionic liquids, [BMIM][NO₃] had a more pronounced inhibition effect, with the activation energies of both ore samples maximally increased by 8.4% and 10.2% after [BMIM][NO₃] treatment. This is due to the ability of [BMIM][NO₃] to better isolate the samples from oxygen in the air and reduce the effective collisions between active molecules, thus inhibiting and retarding the spontaneous combustion of sulfide ores.