DETERMINATION OF THE STATIC MOMENT OF THE RESISTANCE OF THE DRIVE SHAFT OF THE REPLACING MACHINE, CREATED BY THE MASS OF THE BULK ENVIRONMENT IN THE WORK TANK

Among the different types of shredding equipment, which is widely used in various industries of Ukraine, the most promising are machines with complex spatial movement of working tanks. Experimental studies of the movement of the bulk array in the middle of the working tank with transparent walls were performed. The positions of the moving links and the working capacity are set, at which the whole bulk array by its mass will create the greatest value of the static moment of resistance on the driving shaft of the machine. Analytical studies of the static moment of resistance formed on the drive shaft of the machine with complex spatial motion of the working tank as a result of the influence of gravity acting on the bulk array loaded into the tank, the corresponding mathematical dependences are obtained. The obtained research results will be useful in further determining the dynamic moment of resistance on the drive shaft, which will be created by moving the moving parts of the machine and the bulk array in the middle of the tank. Also, the results of research can be used by relevant machine-building enterprises at the stage of designing galvanizing types of equipment with tanks that perform complex spatial movement.

MINIMIZATION OF ELECTRIC CONSUMPTION BY A FREQUENCY-REGULATED INDUCTION MOTOR IN START-BRAKING REGIMES

Purpuse. To minimize the total energy consumption in start-braking regimes of a three-phase frequency-regulated induction motor loaded with a constant static moment, as well as to take into account the effect of iron power losses of this motor on electrical losses of power and energy in its stator winding. Metodology. Based on the established similarity of mathematical dependences for calculating the electrical component of power losses in the stator winding of this motor, caused by the influence of iron power losses of the motor or the application of an additional fictitious static moment to it, the analytical dependences were refined to determine the total power and energy consumed by the motor in steady-state and start-braking regimes. Using the methods of calculus of variations and simulation, the form of energy-saving tachograms was determined, which ensure, in start-braking regimes, the minimization of the total power consumption of this motor, loaded with a constant static torque. Results. Analytical calculated dependencies are proposed for determining the energy consumption in the start-braking regimes of a frequency-regulated squirrel-cage induction motor loaded with a constant static moment, for various types of trajectories of speed change. Analytical dependencies are obtained, by means of which a quantitative assessment of the influence of iron power losses of the investigated motor on the values of the stator current modulus and electrical power and energy losses in its stator winding is carried out under steady-state and start-braking regimes. With regard to the constant load of this motor, the minimization of the active energy consumed by it in the start and braking regimes has been performed. For start-braking regimes with the proposed quasi-optimal and known types of tachograms, the optimal durations of acceleration and deceleration times, at which the consumption of active energy by the induction motor is minimal. Originality. The "U"-shaped form of dependences of the total consumed energy by the frequency-regulated induction motor on the durations of the acceleration and deceleration times has been established. For start-braking regimes, the minimization of the total energy consumed by this motor was carried out and quantified, achieved through the use of energy-saving tachograms and optimal durations of acceleration and deceleration times. Practical value. For start and braking regimes, a quantitative assessment of transient electromechanical and energy processes in a frequency-regulated short-circuited induction motor for driving vertical slab rolls was carried out and the expected annual saving of energy consumed by this motor in these regimes, achieved from the use of the proposed energy-saving tachograms, was determined. Figures 4, tables 5, references 19.

Some Specifications on Calculation of the Static Moment of a Gearbox in Case of Negative Ambient Temperatures

В статье приведены особенности расчета статического момента (момента страгивания) рядного зубчатого редуктора с радиальными шариковыми подшипниками при его работе как в нормальных условиях (плюс 20 °C), так и при отрицательных температурах (минус 40 °C). Выполнен обзор технической литературы по данной тематике, сделан вывод о необходимости уточнения этой области знания. В качестве основных факторов в расчете выделены моменты трения между зубьями передач и потери трения в опорах, которые в числе прочих факторов будут зависимы и от температуры окружающей среды. Для потерь между зубьями приведены теоретические выкладки, на основании которых принято допущение для дальнейшего расчета. Поставлен эксперимент по определению момента страгивания радиальных шариковых подшипников (определенных типоразмеров), получена эмпирическая зависимость. Предпринята попытка получения эмпирических зависимостей для корректировки формул «классического» расчета статического момента редуктора, функционирующего как в нормальных условиях, так и в области отрицательных температур окружающей среды. Проведено сравнение полученных расчетных значений и данных эксперимента на рядных редукторах, применяемых в изделиях предприятия АО «Тайфун».

Experimental investigation of wing-body rock with nonzero equilibrium roll angles

To study wing-body rock, various tests were used for the canard-configuration models in the wind tunnel, including free rolling, disturbance on free rolling, static moment measurements, dynamic derivative measurements, smoke wire method and particle image velocimetry. The models also have a chine forebody, strake wings, main wings and a vertical tail. In the tests, the canard deflection angles are 0° and 20° relative to the axis of the body. First, the roll angle time histories were obtained by free rolling motion and disturbed motion; the results demonstrate that both canard-configuration models have nonzero mean roll angles. In particular, the existence of the other larger nonzero mean roll angles on the same side is a curious aspect at the critical pitch angle, such as at θ = 37° for the model with canard deflection of 20°. Next, static moment tests and dynamic derivative tests demonstrate that although the roll angle time histories are non-limit cycle motions, they are irregularly self-excited oscillation under the influence of multi-vortex structures. Finally, the constituent parts of structures over wing bodies and the flow mechanism of abruptly jumping from an equilibrium roll angle to the other on the same roll side were revealed by the smoke wire and particle image velocimetry measurements.

A Camera Self-Calibration for Machine Vision Based on Kruppa's Equation

A camera self-calibration algorithm based on the Kruppas equation has been put forward by decomposing the fundamental matrix on the basis of computing the geometrical static moment. The fundamental matrix could be estimated through the normalized 8 points algorithm in which the centroid of the irregular polygon was calculated by computing the geometrical static moment. The five intrinsic parameters of a camera were calculated in accordance with the optimal target function established from the simplified Kruppas equation and the linear equation about the five internal parameters of a camera. The experiment showed that the five intrinsic parameters of a camera could be realized by this method.