Improvement of the method of calculation of mechanical characteristics of a traction motor of direct current with combined excitation  Author : Ivan Kostenko  Abstract  Full Text  Abstract :The object of the study is the process of appearing an electromagnetic moment in traction motors of combined excitation of a trolleybus at synchronous inclusion of both components of the excitation system. This process is formally presented as mechanical characteristics – dependence of an electromagnetic moment of the motor from excitation currents.
One of most problem points is to determine the influence of excitation currents of the series and separate winding on an electromagnetic moment of the motor as a continuous dependence that allows to create a system of managing the traction drive with DCDC excitation transformer. Peculiarities of the motor magnetic system are also taken into account.
During the study there was used the method of finite elements in the flatparallel target setting of calculating moments by the results of calculating the magnetic field with the further regression analysis of results of digital experiments using Chebyshev polynomials on the set of equidistant points.
There was received the continuous dependence of an electromagnetic moment from excitation currents as a polynomial that can be used both at creating managing systems DCDC by the excitation transformer and at modeling operation modes of the traction drive as a whole. It is connected with the fact that the offered polynomial type has a continuous type dependency and its derivatives at all possible values of currents at the drive work. According to the results of the regression analysis, the maximal deviation of calculated dependencies doesn’t exceed 0,052, and mean deviation is no more 0,041. It proves the adequacy of the received dependencies to the results of the digital experiment on determining an electromagnetic moment.
Due to it, there is provided the possibility of modeling operation modes of the traction drive based on the motor with combined excitation and DCDC transformer. The managing system parameters, received by modeling results, allow to raise energetic characteristics of trolleybuses. Comparing with analogous known systems, it provides more rational use of electric energy on thrust of the rolling stock. 
 Development of method of increasing accuracy of measuring angular velocity and acceleration of gyrostabilized platform  Author : Viktor Tsiruk  Abstract  Full Text  Abstract :Modern mobile objects have significantly higher velocities, they are significantly more overloaded and uncontrollable mechanical disturbances (shocks, vibrations). Therefore, the requirements for the accuracy of means and methods for measuring the abovedefined mechanical values of the instrument navigation complex have become much higher. However, the imperfection of the element base, the absence of new modern sensitive elements, the lack of the use of a new improved shock protection system, the lack of modern algorithmic methods do not allow to significantly improve accuracy and improve tactical and technical characteristics.
The object of research in this work is the process of measuring the angular velocity and acceleration of a gyrostabilized platform.
Ensuring the accuracy of the arms stabilizer is the most important modern problem, the solution of which ensures the security of Ukraine. According to tactical characteristics, the new weapon stabilizer expands combat capabilities of armored vehicles due to more precise guidance and stabilization on the target, facilitates the crew’s ability to control the tower.
Instrumental weapon stabilizer complexes are designed for stabilized guidance and tracking in the horizontal and vertical planes of surface, air and surface targets. The use of a modern element base has significantly improved the characteristics of the entire range of the weapon stabilizer. According to the technical characteristics of the arms stabilizer, it expands the combat capabilities of armored vehicles through more precise guidance and stabilization on the target, facilitates the crew’s ability to control the tower. And also does not require redirection to the same goal after the shot.
In this paper, an algorithm is considered that is applied when adjusting the position of the implement relative to the target during rapid joint movement of the tower and the machine. The algorithm is calculated in the mathematical block of the stabilization system. The algorithm is based on a mathematical analysis of the theory of motion of gyroscopes and improved from previous ones by supplementing the equation of motion. The formula is derived in the analytical form for its further application in the mathematical blocks of the stabilization system and calculations are given, as a result of which a mathematical model is obtained. If this mathematical model is introduced into the algorithmic block of the stabilization system, this will improve the accuracy of stabilization.
The conclusions analyze the results and give recommendations on the application of the method. 
 Experimental study and modeling of partial discharge detection system  Author : Yevgeniy Trotsenko, Volodymyr Brzhezitsky, Olexandr Protsenko, Vadim Chumack, Yaroslav Haran  Abstract  Full Text  Abstract :The object of research is an electrical system for detecting partial discharges in a sample of high voltage equipment insulation. To evaluate the insulation state of electrical equipment, various methods for detecting partial discharges have been developed and continue to be improved. The role of modeling, virtual experiment and virtual laboratory lessons has recently increased in all areas of engineering. At the same time, some aspects of modeling the electrical systems for partial discharges detection are practically not studied sufficiently. Modeling is an important additional kind of practical training for a further work with measuring and testing equipment in professional activity. The aim of research is determination of the possibility of using an equivalent circuit simulation model in the research and educational process as an analogue of a system for measuring the characteristics of partial discharges.
To measure the characteristics of partial discharges in samples of highvoltage insulation, a special experimental test stand was assembled. The stand allows testing the physical model of insulation by applying alternating current high voltage. To visualize individual partial discharge pulses on an oscilloscope, a highpass filter was designed and assembled that suppresses the 50 Hz main frequency voltage, and is a 4th order Butterworth filter. The oscillogram of partial discharge pulses that occur near a surface of highvoltage electrode in an insulating gap with an electrical cardboard was obtained. It has been experimentally established that partial discharge impulses of different amplitudes arise in the insulating gap with an explicit polarity effect. The experimental oscillogram was adopted as a sample, to which the oscillogram should approach in the simulation. The electrical equivalent circuit for insulation is represented by a traditional threecapacitive equivalent circuit for a dielectric with a gas cavity.
As a result of the research it was established that it is possible to obtain results close to those observed in the physical experiment. The possibility of modeling partial discharges in a dielectric in the presence of two or more gas cavities is shown. 
 Analysis and generalization of the results of an experimental research of the rechargeable batteries of selfguided electric torpedo CET65 (USSR) in postguarantee terms of exploitation  Author : Igor Biryukov, Alexey Biryukov, Oleksandr Shcheptsov  Abstract  Full Text  Abstract :The object of research is the process of changing the electrical and tactical and technical characteristics of silverzinc torpedo batteries during their postwarranty storage.
The subject of research is the technical gerontology of electrotechnical systems, namely silverzinc storage batteries of the selfguided electric torpedo ???65 (USSR).
Available in service silverzinc torpedo batteries are on postwarranty storage terms: from 30 years and more. The changes in their parameters that passed during this period, as well as the gerontological processes taking place in them, have been little studied. In conditions of forced operation on postwarranty storage terms, there is an urgent need to monitor their condition. Proceeding from this, the identification of regularities in the change in the electrotechnical characteristics of silverzinc torpedo accumulator batteries from their storage times and determining the impact of these changes on the main tactical and technical characteristics of the torpedo is an important scientific and applied problem.
The model of life cycle of silverzinc batteries is analyzed. This allows to predict the changes in the basic electrical characteristics from the time of their storage, as well as the impact of these changes on the main tactical and technical characteristics of the torpedo. The dependences of the effect of the torpedo storage period for more than 20 years on the intensity of the decrease in its speed and the range of its course are determined. It is found that these indicators deteriorate to 20 % and 17 %, respectively. Correction of the model of the life cycle of the torpedo battery is carried out. It is established that taking into account the operation of the automatic guidance system, the period of expedient operation of the torpedo battery should not exceed 16 years. Based on the gerontological changes in the power supply sources of the torpedo battery, a method for correcting torpedo firing is proposed. This will compensate for the increase in the scattering in the lateral direction and in range, as well as the increase in the angle of the calculated point of the torpedo encounter with the target. In turn, this will allow performing training and combat missions using the available torpedoes of postwarranty storage periods. 
 Analysis of distribution laws of insulation indicators of highvoltage oilfillled bushings of hermetic and nonhermetic execution  Author : Oleg Shutenko, Alexandra Zagaynova, Galina Serdyukova  Abstract  Full Text  Abstract :The object of research is the distribution laws of capacitortype insulation values that were obtained during preventive tests for both serviceable and defective highvoltage bushings of 110 kV of hermetic and nonhermetic execution. One of the most problematic areas is insufficient knowledge and lack of justification of the laws for distributing these preventive tests of insulation of bushings.
In the course of the research, a comprehensive approach to the solution of the problems was used, including probability theory and statistical analysis, analysis of world experience and a logical approach. In the long term, the results are expected to be extended to the bushing of other types having similar problems in the diagnosis of the condition.
The method of statistical processing of the results of periodic tests of highvoltage bushings is proposed, which allows to form arrays with homogeneous values of indicators in conditions of limited measurement information. It is established that for the bushings of hermetic and nonhermetic execution, the insulation values for both the serviceable and faulty state can be described by the Weibull distribution. It is established that the distribution densities for serviceable and faulty state of highvoltage bushings intersect, and therefore it is impossible to select the maximum permissible values of insulation parameters that would not give erroneous solutions. The maximum permissible values of the insulation indices of highvoltage oilfilled bushings are proposed using statistical methods and taking into account the most significant operational factors. It is shown that for highvoltage bushings of the same execution there is a shift in mathematical expectations, which is due to the difference in operating time and different load factors of transformers. This circumstance must be taken into account when adjusting the maximum permissible values of the insulation indices of highvoltage bushings.
The use of the developed algorithms and procedures of mathematical statistics in the problems of diagnosing highvoltage bushings contribute to improving expert judgment and decisionmaking. 
 Influence of external factors on the process of hydrates development in laboratory conditions  Author : Nashwan Abdullah, Bohdan Kutnyi  Abstract  Full Text  Abstract :The object of research is the influence of various factors on the process of synthesis of propane hydrate in laboratory conditions. It is known that a synthesized gas hydrate can contain a significant amount of ice, which reduces its gas content. The quality of the hydrate is affected by: gas pressure, water temperature, time of the experiment and the concentration of surfactants.
To study the complex effect of these factors on the quality of the hydrate obtained, an experimental setup is developed. After synthesis of the gas hydrate, its gas content is determined using a specially designed stand. In the course of the research, various measuring instruments were used: manometers, thermometers, measuring utensils, electronic scales, etc., which made it possible to obtain reliable information on the thermophysical characteristics of the synthesis and dissociation of gas hydrate.
As a result of the multivariate experiment, an array of data for analysis by mathematical statistics methods is obtained. Correlation coefficients are determined and found that the dominant factors are the gas pressure and concentration of surfactants. The water temperature should be within the operating range of 1–5 °C. The formation time of the hydrate in the bubbling regime within 0.5–5 h also does not significantly affect the quality of the obtained hydrate. For all factors, regression dependencies and graphs are constructed. It is established that for standard regression dependencies (linear, exponential, logarithmic and polynomial), the coefficients of multiple correlation are in the range 0.19–0.46. This means that the standard regression relationships do not allow to take into account all the features of the obtained results. Therefore, the selection of the optimal dependence is carried out by the method of variation of the coefficients and types of functional dependencies and an approximate formula is obtained for determining the predicted gas content of the hydrate.
The research results show that due to the complex consideration of various factors, it is possible to determine the range of optimum values of pressure, temperature and concentration of surfactants, which makes it possible to quickly produce a highquality hydrate. 
 Study into energy efficiency of the drive of electric vehicles with an independent power supply depending on the configuration of the power source  Author : Mykola Ostroverkhov, Danylo Trinchuk  Abstract  Full Text  Abstract :The electric vehicle with an independent power supply is the object of this research. At present, such vehicles are becoming more popular in the automobile market, pushing out their rivals with internal combustion engines, owing to their superior energy efficiency. The advantage over the internal combustion engine vehicles being obvious, the efficiency of electric vehicles is still considerably low in comparison to other electric devices. The problem that causes these limitations lies in the power supply – liion accumulator – which has high impedance.
In order to solve this disadvantage, the system with an ultracapacitor battery connected in parallel to the accumulator was considered using an example of the electric scooter drive with a squirrelcaged induction motor. Ultracapacitors have significantly lesser impedance than accumulators, thus they carry with themselves most of instant load during acceleration and braking when a power source supplies the highest currents.
Our study has shown that this configuration improves energy efficiency of the electric vehicles. Moreover, there is an optimal amount of ultracapacitor capacitance for achieving the best efficiency (the lowest energy consumption). This follows from the fact that an ultracapacitor battery is a rather heavy object; a significant increase in its capacitance leads to the increased vehicle weight and thus enhances energy consumption. An additional modernized system of supply was considered at which ultracapacitor’s charging is accelerated during vehicle stops. Such a system has made it possible to improve the results and decrease energy consumption even larger.
Compared to previous studies, this research demonstrates the importance of correct choice of ultracapacitor capacitance and supply distribution system. The existence of the optimum point has been proven; the difference of energy consumption at this point has been demonstrated in numbers. 

