Vibrations in engineering and technology

Trehub Mykola – Doctor of Technical Sciences, Professor, Head of the Department of Electric Power Engineering, Electrical Engineering and Electromechanics, Bila Tserkva National Agrarian University (8/1 Soborna Square, Bila Tserkva, Kyiv Region, Ukraine, 09117; e-mail: tregyb.m.i@gmail.com; ORCID: https://orcid.org/0000-0001-6558-0040).

Chervinskyi Leonid – Doctor of Technical Sciences, Professor, Professor of the Department of Electrical Engineering, Electromechanics and Electrotechnology, National University of Life and Environmental Sciences of Ukraine (15 Heroiv Oborony St., Kyiv, Ukraine, 03041; e-mail: lchervinsky@gmail.com; ORCID: https://orcid.org/0000-0001-7215-2474).

Tarasiuk Oleh – Head of Department, DTEK Kyiv Regional Electric Networks (Apt. 172, 18 Boholiubova St., Sofiivska Borshchahivka Village, Kyiv Region, Ukraine; e-mail: oleg535135@gmail.com).

Demchenko Viktor – Candidate of Technical Sciences (PhD), Associate Professor of the Department of Energy, Electrical Engineering and Electromechanics, Bila Tserkva National Agrarian University (8/1 Soborna Square, Bila Tserkva, Kyiv Region, Ukraine, 09117; e-mail: bnauelectro@gmail.com).

Constructive and technological approaches to the design and engineering calculation of a gearless electric generator for a vertical-axis wind turbine with a disc rotor and permanent axial-type neodymium magnets have been developed. The study focuses on improving the generator design, selecting structural and magnetic materials, and increasing the reliability, manufacturability, and durability of the electromechanical system. An analysis of the rotor pole arrangement schemes was carried out, and the influence of the magnetic system geometry on the generator operating characteristics was determined. The generator parameters were calculated using a graphical-analytical method based on the characteristics of high-coercivity Nd-Fe-B magnets and electrical steel.

The feasibility of using an axial-type disc rotor capable of accommodating a large number of poles within relatively small dimensions has been substantiated. Such a design corresponds to modern trends in Industrial Mechanical Engineering, where compactness, energy efficiency, and long service life of electromechanical systems are of primary importance. The disc rotor configuration increases the peripheral velocity of magnetic poles and improves the efficiency of energy conversion. Structural loads arising during rotor operation were analyzed, and requirements for stiffness and manufacturing accuracy of the main generator components were determined.

Particular attention was paid to the structural strength and manufacturability of generator components. The study investigated the machining features of the disc rotor, concentricity control, balancing, and assembly accuracy. It was established that the precision of permanent magnet installation directly affects magnetic flux uniformity, operational stability, and vibration reduction. The design features of the modular stator were considered, providing simplified assembly and improved maintainability of the system. The operation of bearing units, conditions of mechanical losses, and methods for increasing the durability of rotating elements were also analyzed.

Considerable attention was devoted to materials science aspects of the generator magnetic system design. The application of high-coercivity Nd-Fe-B permanent magnets was substantiated due to their high residual magnetic induction, coercive force, and magnetic energy density. It was established that the use of such magnets significantly reduces the weight and dimensions of the generator while simultaneously increasing its energy efficiency. The influence of temperature conditions on the stability of magnetic properties was investigated, and permissible operating conditions for the magnets were determined. The properties of electrical steel used for magnetic cores were also analyzed, considering magnetic permeability, eddy current losses, and resistance to cyclic remagnetization.

Mechanical properties of structural materials used for the rotor and housing elements were studied separately. The influence of cyclic loads, vibrations, and dynamic operating conditions on the durability of the structure was analyzed. Requirements for the stiffness of rotor and stator materials were established to ensure geometric stability during operation. Particular attention was paid to the manufacturability of generator components and the maintainability of the structure.

A structural design of a vertical magnetic suspension system was proposed, allowing axial loads on rotor supports to be reduced, friction losses minimized, and generator durability increased. It was established that the use of magnetic suspension improves the service life of friction units and enhances the operational characteristics of the electromechanical system.

For typical operating conditions of a vertical-axis wind turbine, calculated energy performance indicators of the generator were obtained and confirmed by experimental studies of a laboratory prototype. Bench tests made it possible to evaluate the efficiency of the proposed design under real operating conditions. Good agreement between theoretical and experimental results was established, confirming the effectiveness of the proposed structural, technological, and materials science solutions. The research results demonstrate the prospects of using gearless axial-flux disc generators in modern low-power energy systems.

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