The article deals with the indirect methods for calculating the temperature of asynchronous generators with the introduction of a pulse component in the power supply circuit of the stator windings of asynchronous generators with squirrel-cage rotor. The relevance of this issue is determined by the need to improve asynchronous energy converters to increase their reliability and safety. The object of the study is an asynchronous generator with squirrel-cage rotor, which consume 40 % of the total electricity generated, and are the most affordable. One of the dangerous modes of asynchronous generators is their overheating as a result of increased currents and temperatures. The thermal protection of the stator winding of asynchronous generators relies primarily on measuring or determining the winding temperature. An indirect method for determining temperature based on measuring the resistance of the stator of an asynchronous generator with squirrel-cage rotor is proposed. The method is based on superimposing pulse signals of small amplitude and high frequency of 600 Hz on an alternating sinusoidal voltage with a frequency of 50 Hz. A simulation model for a 3 kW asynchronous generator has been developed. There were given the simulation results. The estimated values of the active resistances of the stator can be used to indirectly determine the temperature of the windings in thermal protection devices of asynchronous generators, as well as for control, monitoring and diagnostics of the technical condition. The research results confirm the possibility of indirect temperature determination and the creation of a thermal protection system for asynchronous energy converters based on the use of estimation methods.

More than 60 % of electric energy in industry and agriculture is consumed by an electric drive. In a number of production mechanisms, machines and aggregates of various industries, synchronous rotation of several electric motors connected to each other mechanically, electrically or technologically is needed. This requires the use of more complex methods of controlling electromechanical systems, since two or more electric motors must work in concert for one load, which, in turn, entails the use of a new element base, power and control, allowing to implement these technological cycles of work. The object of research is a three-motor electromechanical system interconnected and operating according to the “electric working shaft” (EWS) system. The main fundamental difference from earlier works is that they consider a system of coordinated rotation of only two asynchronous motors, respectively, only one misalignment angle between two asynchronous motors was taken into account. At the same time, the conclusions of the moments and currents of the motors were significantly simplified. In the proposed study, the number of consistently (synchronously) rotating motors from three and above is taken into consideration. In this case, the number of misalignment angles is assumed to be equal to the number of engines, that is, three involved in rotation. The analytical expressions of the basic electromechanical relations of the “electric working shaft” system with the regulation of the supply voltage are developed. A method is proposed for calculating the statistical characteristics of the regulated EWS system, which is easy to use and allows calculations in a wide range of rotor misalignment angles at various engine loads

The interaction of fine particles with an expanding gas flow under fluidization conditions is considered. The objects of study are finely dispersed materials, their single particles, gas flow in a fluidized layer. The study used the laws of dynamics and hydrodynamics, the classical laws of mechanics, as well as mathematical methods for the analytical solution of equations. It is emphasized that when a particle moves upwards in a gas jet, three forces act on it: the resistance force Fc, the gravity force P, and the Archimedes force A. As a result, the motion of a fine particle in an expanding gas flow is described taking into account the law of dynamics. During the study, an analytical equation was obtained to determine the velocity of a particle during its rise and fall in a gas jet. During the study, an analytical equation was obtained to find the height of the particle ascent depending on the gas flow rate for given geometric parameters of the gas flow. The obtained formulas can be used in the process of studying the process of convective drying of finely dispersed materials for various design parameters of the dryer. In practice, as a rule, there are various empirical formulas that describe such interactions of particles for specific parameters, which make it difficult to generalize them. In this work, the correctness of the assumed conditions necessary for the analytical solution of the differential equation of particle motion is proved. As a result, formulas were obtained that make it possible to determine the velocity of a particle in a gas jet and the height of its rise depending on the gas flow rate. On the basis of these formulas, graphic dependences of the gas velocity in the jet on the height Vg=f(Z), as well as the dependences of the height of the particle rise hm on the air flow rate in the jet L at different jet expansion angles α=15°; α=20°; α=30° are plotted. It was found that with an increase in the height Z in an expanding jet, the gas velocity in the jet Vg decreases, with an increase in the air flow rate in the jet L, the height of the particle rise hm increases. These formulas are the basis for further consideration of the movement of particles in a fluidized layer in the process of convective drying of fine materials for its intensification of the drying process

One of the most common types of AC electric machines are asynchronous electric motors. Because of their simple and reliable design, they are used in many industries. In this paper, the object of research is an asynchronous electric motor with a short-circuited rotor. To ensure the normal operation of an asynchronous electric motor, the heating temperature of its active parts should not exceed the maximum permissible values, which are determined by the corresponding class of heat resistance of the insulation system used in the electric motor. In asynchronous electric motors, the stator winding is the most thermally vulnerable node, which is the first to fail when the temperature of the electric motor increases. Thermal protection devices protect an asynchronous electric motor from emergency operating modes accompanied by an unacceptable excess of the temperature of their windings. In order to build an indirect system of protection against overheating of the stator windings, a temperature observer has been developed using already available signals in a frequency-controlled electric drive. Simulation studies were performed in Matlab/Simulink application software packages. Simulation studies were carried out on the basis of asynchronous electric motors of the 4A series with a capacity of 30, 75 and 110 kW in the temperature range from 20 °C to 250 °C. As a result of the research, it was found that the error of indirect calculation of the temperature of electric motors, taking into account the correction factor, does not exceed 1 %. The proposed temperature observer can be used to build protections for asynchronous electric drives

The increasing deployment of wind turbines in technologically advanced nations underscores the need to enhance their reliability, extend their operational lifespan, and minimize failures. The current protection devices for wind turbine components do not sufficiently shield them from various external factors that degrade performance. This study addresses the environmental and technical challenges that disrupt wind turbine operations and reviews existing research and technical solutions for protecting individual components, supported by experimental findings. Using a decomposition method followed by the integration of protection components, we propose a combined protection system designed to improve the overall resilience of wind turbines. The proposed system aims to reduce incidents, extend service life, and increase reliability, addressing a critical gap in wind energy technology and contributing to its continued development and efficiency.

The object of research is a wind generator with counter-rotating blades. A special feature of this design is the presence of two wind wheels that rotate in opposite directions. Wind wheels are on the same axis, between them there is a certain distance, which is determined based on research data. The problem of modern wind power is the low range of operating wind speeds, weak generation at low wind speeds. The upper speed limit is 25 m/s, exceeding which leads to breakdowns of various units of the wind station, especially this affects the integrity of the blades, rupture of the wind wheel, cracking of the metal parts of the bearings and their fasteners. The wind turbine presented in the article allows to achieve an increase in the generation of electric energy by 50–70 %. This is achieved by increasing the relative rotational speed of the rotor relative to the stator. Therefore, even at low speeds, the rotor speed relative to the stator increases, which leads to an increase in power generation. The design of the device includes: two wind wheels, one transmits its rotation to the stator, the second to the rotor axis, a metal base, a current collector mechanism. For conducting the research, an experimental model and a semi-industrial installation were used. Results studies have confirmed the theoretical increase in the generation of electrical energy by this design. The peculiarity of the obtained results is connected with the determination of the distance between two wind wheels, the optimal distance between them corresponds to the maximum energy generation. A distinctive feature of the results obtained can be considered an increase in the number of blades on the second wind wheel Об’єктом дослідження є вітрогенератор із зустрічно обертовими лопатями. Особливістю такої конструкції є наявність двох вітрових коліс, які обертаються в протилежних напрямках. Вітрові колеса знаходяться на одній осі, між ними є певна відстань, яка визначається на основі даних досліджень. Проблемою сучасної вітроенергетики є низький діапазон робочих швидкостей вітру, слабка генерація при малих швидкостях вітру. Верхня межа швидкості становить 25 м/с, перевищення якої призводить до поломок різних вузлів вітрової станції, особливо це позначається на цілісності лопатей, розриві вітрового колеса, розтріскування металевих частин підшипників та їх кріплень. Представлений у статті вітрогенератор дозволяє досягти збільшення вироблення електроенергії на 50–70 %. Це досягається збільшенням відносної швидкості обертання ротора відносно статора. Тому навіть при низьких швидкостях обертання ротора відносно статора зростає, що призводить до збільшення вироблення електроенергії. У конструкцію пристрою входять: два вітрових колеса, одне передає своє обертання на статор, друге на вісь ротора, металева основа, струмоприймальний механізм. Для проведення досліджень використовували експериментальний макет і напівпромислову установку. Результати досліджень підтвердили теоретичне збільшення генерації електроенергії цією конструкцією. Особливість отриманих результатів пов'язана з визначенням відстані між двома вітровими колесами, оптимальна відстань між якими відповідає максимальному виробленню енергії. Відмінною особливістю отриманих результатів можна вважати збільшення кількості лопатей на другому вітровому колесі