Problems of Tribology = Проблеми трибології - 2025 рік

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https://elar.khmnu.edu.ua/handle/123456789/18103

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Перегляд Problems of Tribology = Проблеми трибології - 2025 рік за Ключові слова "bearing internal clearance"

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    Analysis of the influence of radial clearance in a bearing on its operating modes, taking into account mass and magnetic imbalance of the induction motor rotor
    (Хмельницький національний університет, 2025) Goroshko, A.; Zembytska, M.
    The article studies the problem of the journal motion of a three-phase induction motor rotor in a bearing. A simplified model of the journal motion is studied at the moment of journal separation and transition from the pendulum mode of journal motion to the impact mode. In this case, the elastic-damping properties of the bearing and the final rigidity of the rotor are ignored. The model takes into account the eccentricity of the rotor mass and the radial internal clearance of the bearing. In addition, the forces of unbalanced magnetic pull (UMP) caused by the magnetic eccentricity of the induction motor rotor, which is caused by the radial clearance of the bearing, are taken into account. It is analytically shown that the forces of UMP cannot be ignored, since even the rated clearance of bearings of low- and medium-power motors causes an unbalanced force commensurate with the force caused by the eccentricity of the mass. Using numerical modeling and simulation for a three-phase induction motor with a squirrel-cage rotor with a power of 11 kW and a speed of 3000 rpm, the dependences of the critical frequency of the journal separation from the bearing for different values of the mass eccentricity and radial clearance are presented. It is shown that without taking into account the UMP, an increase in the radial clearance leads to a decrease in the critical separation speed. In this case, a bearing with a passport radial clearance is able to switch to the mode of periodic impacts of the journal at a speed lower than the nominal speed of rotation of the rotor with an acceptable eccentricity. Taking into account the UMP, on the contrary, it significantly increases the value of the critical separation speed. At the same time, it is necessary to take into account that with an increase in UMP, the radial load on the bearing also increases, which in turn leads to increased wear of the bearing.