Induction Motor Vibrations Caused by Mechanical and Magnetic Rotor Eccentricity

Author(s): Goroshko A. V.*, Zembytska M. V., Paiuk V. P.

Affiliation(s): Khmelnytskyi National University, 11, Instytutska St., 29016 Khmelnytskyi, Ukraine

*Corresponding Author’s Address: [email protected]

Issue: Volume 11, Issue 1 (2024)

Dates:
Submitted: January 12, 2024
Received in revised form: April 16, 2024
Accepted for publication: April 30, 2024
Available online: May 3, 2024

Citation:
Goroshko A. V., Zembytska M. V., Paiuk V. P. (2024). Induction motor vibrations caused by mechanical and magnetic rotor eccentricity. Journal of Engineering Sciences (Ukraine), Vol. 11(1), pp. D66–D77. https://doi.org/10.21272/jes.2024.11(1).d8

DOI: 10.21272/jes.2024.11(1).d8

Research Area: Dynamics and Strength of Machines

Abstract. Vibration reduction of induction motors is a significant problem that requires effective models for the effects of mechanical and electromagnetic unbalanced forces. This article presents a mathematical model of dynamics for induction motors with rotor mass eccentricity and static and dynamic magnetic eccentricity. The model allows for the influence of the gyroscopic torque of the rotor and considers the elastic-damping characteristics of each of the stator supports and their location. The model has eight degrees of freedom, which makes it possible to simulate transverse and axial vibrations of various designs’ rotors and housings of induction motors. The results of modeling the dynamics for a three-phase squirrel cage induction motor with 11 kW capacity agreed with those obtained by other authors. Simultaneously, new results were also obtained within the research. The simulation results showed that the static magnetic eccentricity causes the appearance of additional critical speed of the motor, and its value decreases in proportion to the growth of the number of pole pairs. The change of the moment of inertia of the motor at a mismatch of the main axis of symmetry of the stator and the rotor axis of rotation allowed for obtaining an actual frequency spectrum of free oscillations, including the rotational motion of the stator. Since the actual static magnetic eccentricity can additionally increase at operating frequencies due to the increase of bearing clearance caused by dynamic unbalanced load, it should be considered in the analysis of unbalanced magnetic pull. The angle of static magnetic eccentricity significantly affects the magnitude of radial vibrations. This feature should also be considered when selecting the locations of balancing weights during the rotor balancing procedure.

Keywords: induction motor, eccentricity of rotor mass, magnetic eccentricity, unbalanced magnetic pull, axial vibration, process innovation.

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