Research of the Modes of Starting and Braking during Work of the Systems of Group Electric Drive of Mine Electric Locomotive with the Different Types of Electric Engines

In the article the results of research of work of mine electric locomotive are driven on condition of stability of the system "A wheel is a rail" on coupling of wheels of electric locomotive with rails. It is marked that work of mine electric locomotive transport is conditioned by the row of specific terms. It is indicated that for realization of the electromechanics systems of mine electric locomotives structures are used with the hauling electric engines of direct and variable current. During working as of mine electric locomotive an important question there is coupling of wheels of electric locomotive with rails. Investigation of worsening of coupling of wheel with a rail is an origin of processes of skidding in the mode of creation of tractive or юза force in the mode braking of electric locomotive, that influence negatively for other knots of hauling electromechanic. In turn stability of the system "A wheel is a rail" depends on the type of hauling electromechanic. At consideration condition of stability of electromechanic on coupling of wheels of electric locomotive with rails important is inflexibility of descriptions of hauling electric motors. What more inflexibility, the higher stability of the system "A wheel is a rail". More hard descriptions can be got in the system of electromechanic with hauling asynchronous engines that give an opportunity to use this fact for realization of proportional distribution of efforts between the wheelpairs of electric locomotive. The systems ticker-coil on speed allow to carry out distribution of hauling and brake efforts that is attached to the wheelpairs of electric locomotive, in accordance with distribution of efforts from these wheelpairs on rails, only after the beginning of processes of skidding or skidding. For the decision of this problem a sufficient condition there is a limit of currents of hauling electric motors on the set level. In this connection possibility of distribution of hauling and brake efforts appears at any moment to time. For the decision of task of rational distribution of efforts of electric locomotive, distribution of forces was analysed between his wheelpairs in the function of total force that pulls an electric locomotive on his coupling. On the basis of analysis an idea was got about the redistribution of loading on the axes of electric locomotive. This distribution is in direct ratio to his total tractive force and coupling height, and in inverse ratio to inflexibility of corps. As a result, in order that propelling and brake forces on the axes of electric locomotive corresponded to distribution of weight on rails on wheelpairs, it is necessary to support identical correlation of weight and efforts on the axes of electric locomotive. The design of transients was conducted in the system of group electric hauling drive of mine electric locomotive in the mode of starting and braking. A design is executed for the engine of direct-current with successive connection of poles and hauling asynchronous engine. The charts of transients in the system of group electric hauling drive of mine electric locomotive in the mode of starting and braking showed absence of processes of skidding and slipping at application of the offered principle for the control system.

Study on an Analytical Solution to the Mechanical Response of Soil Cut by a Bionic Force Enhancement Grouser

With the depletion of land mineral resources, people have turned their attention to the sea. As an important part of deep-sea mining systems, the technical research and development of ore collectors has always been a difficult problem in many countries. According to the characteristic that buffalo hoof is suitable for walking on soft soil, a kind of bionic grouser for a deep-sea mining vehicle is designed in this paper. Through the optimization of Rankine’s passive earth pressure theory, the formula for calculating the tractive force of the grouser is obtained. The accuracy of the analytical solution is verified by finite element simulation, and the force enhancement mechanism of the bionic grouser is revealed. The results show that the design of the bionic grouser has a significant effect on the improvement of tractive force, and the tractive force of the No. 1 bionic grouser is 17.52% higher than that of the straight grouser. On this basis, the geometric parameters of the bionic grouser profile are optimized. The results show that when L is 0 mm and R is 183 mm, the force enhancement effect reaches the maximum of 27%, which provides a design basis for optimizing the grouser and improving the mining efficiency of the collector.

Entropy-Based Shear Stress Distribution in Open Channel for All Types of Flow Using Experimental Data

Korean river design standards set general design standards for rivers and river-related projects in Korea, which systematize the technologies and methods involved in river-related projects. This includes measurement methods for parts necessary for river design, but does not include information on shear stress. Shear stress is one of the factors necessary for river design and operation. Shear stress is one of the most important hydraulic factors used in the fields of water, especially for artificial channel design. Shear stress is calculated from the frictional force caused by viscosity and fluctuating fluid velocity. Current methods are based on past calculations, but factors such as boundary shear stress or energy gradient are difficult to actually measure or estimate. The point velocity throughout the entire cross-section is needed to calculate the velocity gradient. In other words, the current Korean river design standards use tractive force and critical tractive force instead of shear stress because it is more difficult to calculate the shear stress in the current method. However, it is difficult to calculate the exact value due to the limitations of the formula to obtain the river factor called the tractive force. In addition, tractive force has limitations that use an empirically identified base value for use in practice. This paper focuses on the modeling of shear-stress distribution in open channel turbulent flow using entropy theory. In addition, this study suggests a shear stress distribution formula, which can easily be used in practice after calculating the river-specific factor T. The tractive force and critical tractive force in the Korean river design standards should be modified by the shear stress obtained by the proposed shear stress distribution method. The present study therefore focuses on the modeling of shear stress distribution in an open channel turbulent flow using entropy theory. The shear stress distribution model is tested using a wide range of forty-two experimental runs collected from the literature. Then, an error analysis is performed to further evaluate the accuracy of the proposed model. The results reveal a correlation coefficient of approximately 0.95–0.99, indicating that the proposed method can estimate shear-stress distribution accurately. Based on this, the results of the distribution of shear stress after calculating the river-specific factors show a correlation coefficient of about 0.86 to 0.98, which suggests that the equation can be applied in practice.

Design Matching and Dynamic Performance Test for an HST-Based Drive System of a Hillside Crawler Tractor

In recent years, research into and development of hillside tractors has become a popular topic in the field of agricultural engineering in China. To solve the main problems associated with a low adjustment range of the working speed, complex operation, and low safety for slope operation of medium-sized crawler tractors, a hydrostatic drive system that can be used for hillside crawler tractors was designed. According to the operation requirements of a hillside crawler tractor, the parameters of the three-cylinder diesel engine, hydrostatic transmission (HST), drive rear axle, and other key components of the drive system were matched after the force and motion analyses of the tractor, and then the main performance indicators, including the traction performance, system pressure and working speed of the drive system were verified. On this basis, a drive system performance test bench was built, and the traction performance and starting acceleration performance of the drive system was tested. The results of the traction bench test show that when the engine was at the maximum torque point of 1700 r/min, the maximum theoretical tractive force outputted by the tractor in Gear I was 114,563 N, and the maximum theoretical tractive force outputted by tractor in Gear II was 10,959.2 N, which were both larger than the traction resistance of 9550.6 N experienced by the hillside tractor ploughing on the slope. The results of the initial acceleration bench test show that the tractor driving speed can gradually increase with increasing output of the variable pump and can reach the maximum in 3 s. When the tractor was driving on flat ground, the maximum driving speeds of Gear I, Gear II, and Gear III were 4.65 km/h, 6.58 km/h, and 8.57 km/h, respectively, which are close to the theoretical values. When the tractor was driving on a 15° slope, the maximum driving speeds of Gear I, Gear II, and Gear III were 4.55 km/h, 6.25 km/h, and 8.28 km/h, respectively. It can be concluded that the design matching of the drive system is reasonable, the speed consistency is good and there is enough power reserve, which can meet the requirements for a large workload.

Entropy-Based Shear Stress Distribution in Open Channel for all types of Flow using Experimental Data

Korea’s river design standards set general design standards for river and river-related projects in Korea, which systematize the technologies and methods involved in river-related projects. This includes measurement methods for parts necessary for river design, but do not include information on shear stress. Shear Stress is to one of the factors necessary for river design and operation. Shear stress is one of the most important hydraulic factors used in the fields of water especially for artificial channel design. Shear stress is calculated from the frictional force caused by viscosity and fluctuating fluid velocity. Current methods are based on past calculations, but factors such as boundary shear stress or energy gradient are difficult to actually measure or estimate. The point velocity throughout the entire cross section is needed to calculate the velocity gradient. In other words, the current Korea’s river design standards use tractive force, critical tractive force instead of shear stress because it is more difficult to calculate the shear stress in the current method. However, it is difficult to calculate the exact value due to the limitations of the formula to obtain the river factor called the tractive force. In addition, tractive force has limitations that use empirically identified base value for use in practice. This paper focuses on the modeling of shear stress distribution in open channel turbulent flow using entropy theory. In addition, this study suggests shear stress distribution formula, which can be easily used in practice after calculating the river-specific factor T. and that the part of the tractive force and critical tractive force in the Korea’s river design standards should be modified by the shear stress obtained by the proposed shear stress distribution method. The present study therefore focuses on the modeling of shear stress distribution in open channel turbulent flow using entropy theory. The shear stress distribution model is tested using a wide range of forty-two experimental runs collected from the literature. Then, an error analysis is performed to further evaluate the accuracy of the proposed model. The results revealed a correlation coefficient of approximately 0.95–0.99, indicating that the proposed method can estimate shear stress distribution accurately. Based on this, the results of the distribution of shear stress after calculating the river-specific factors show a correlation coefficient of about 0.86 to 0.98, which suggests that the equation can be applied in practice.

APPLICATION OF LINEAR ASYNCHRONOUS MOTORS FOR HIGH-SPEED GROUND TRANSPORT

Magnetic suspension in high-speed ground transport systems is an alternative to the rail wheel. The successful solution to the development of high-speed ground transport is largely determined by the creation of operationally efficient linear motors, the main task of which is to convert electrical energy into mechanical energy and create tractive force to ensure the movement of the crew according to a given program in the range of operating speeds. The article investigates linear asynchronous motors with longitudinal closure of magnetic flux of single-ended design. As a result of investigation of physical processes in linear motors caused by edge problems it was found that the cause of the transverse edge effect is the finite width dimensions of the reactive bus, the change of which causes closure of eddy currents within the active area of inductor, leads to weakening of magnetic field in the central zone and to reduction of tractive force. The discrepancy between the calculated and experimental indicators of physical processes in linear asynchro- nous motors due to significant idealization of mathematical models led to the development of a three-dimensional theory, brought to the calculation programs. The developed calculation program of electromechanical characteristics of linear induction motors with inductor and reactive bus layout, as well as their geometrical and physical parameters allows to determine the necessary integral motor characteristics in the form of a levitation function.

Study of Three-Point Linkage of Power Machine

The three-point linkage serves to interconnect the power machine and the suspended or semi-suspended work machine. It has a role in the operation of the machine group, in towing and in the setup of the machines. Part of the weight of the suspended machine is loaded on the driven wheels, thus increasing the adhesion weight which results in an increase in the tractive force. Understanding the operation of this equipment it is necessary for horticulture, agronomy and landscape architecture future engineers. In this thesis we model the effect of connection points of the three-point linkage on the tractive force in a specific case: that of the suspended plow.

Experimental Stand Movable Module for Determining the Traction-Linked Properties of Wheel Engines and the Results of Laboratory Researches for Determining the Traction Force of Two-Wheel Tractors

Introduction. Farmers make extensive use of two-wheel tractors equipped with traction and drive interchangeable units. Two-wheel tractors are required to move evenly with minimal slip of the drive wheels on the soil. The tractive force on the drive wheels of the tillage unit is the decisive power factor in this case. An objective traction force value can be measured only by carrying out experimental studies. Materials and Methods. To determine the traction force on the drive wheels of the twowheel tractor, the design of the experimental stand was proposed and substantiated (RF patent for useful model No. 188610 “Movable module of the test stand”), and a methodology for planning and conducting a multifactor experiment to determine the traction force was developed. Results. As a result of the laboratory tests the calculation dependencies of the tractive force on the drive wheels of the Neva MB23-MultiAGRO Pro two-wheel tractor were obtained. Soil conditions, design and technological parameters, operating modes of the two-wheel tractor, and rolling resistance forces were taken into account. Discussion and Conclusion. The use of the developed regression models of the traction force under the condition of ensuring uniform movement with the minimum permissible slipping of the driving wheels of the two-wheel tractor on the soil will allow obtaining the permissible values of the two-tractor motion speed and form the zones of its most effective functioning.