Characteristics of Hydraulic and Electric Servo Motors

Until the 1970s, hydraulic actuators were widely used in many mechanical systems; however, recently, electric motors have become mainstream by virtue of their improved performance, and hydraulic motors have largely been replaced by electric motors in many applications. Although this trend is expected to continue into the future, it is important to comprehensively evaluate which motor is most suitable when designing mechanical systems. This paper presents the results of a survey of the performance of electric and hydraulic servo motors and aims to provide quantitative data that can be used as a reference for selecting appropriate motors. We surveyed AC, AC direct, brushless DC, and brushed DC electric motors and swash plate-type axial piston, bent axis-type axial piston, crank-type radial piston, and multistroke-type radial piston hydraulic motors. Performance data were collected from catalogs and nonpublic data. We compared and evaluated the characteristics of these diverse servo motors using indexes such as torque, rotating speed, output power, power density, and power rate.

Simulation Modeling of a Ship Propulsion System in Wavesfor Control Purposes

The article deals with a simulation approach to the representation of the ship motions in waves, interacting with the propulsion system behavior (diesel engine and propeller). The final goal is the development of a simulator, as complete as possible, that allows the analysis of the main engine thermodynamics in different sea conditions, also in the unfavorable event of dynamic instability of the hull, and the correct management of the other propulsion components. This latter aspect is particularly interesting in some of the last new energy solutions for decarbonization of ships, concerning, for example, auxiliary electric motors, powered by batteries, to support the traditional diesel-mechanical propulsion (especially in heavy weather conditions). From this point of view, a proper analysis of the engine dynamic performance, affected by particular sea states, is fundamental for a smart management and control of shaft generators/auxiliary electric motors, batteries, etc. To this end, the work presents and highlights the main features of a ship simulator, suitable for the study of the new propulsion solutions that are emerging in maritime transport. Some representative results will point out the complex non-linear behavior of the propulsion plant in waves. Moreover, a parametric roll scenario will be investigated, in order to highlight the capability of the conceived simulator in modeling the effects of the dynamic instability of the hull on the propulsion plant.

Analysis of depolymerization of insulating compositions of electric motor windings based on ultrasonic radiation

This work is a continuation of the fundamental study on implementing an innovative method of repairing electric motors using ultrasound. A study of the method of dismantling windings based on ultrasound has been carried out for the purpose of energy efficiency, environmental friendliness and less time spent on the repair cycle of electric motors in terms of removing the stator winding. The investigated dismantling method is optimal for a number of technical issues in comparison with the existing methods for dismantling electric motor windings. In the work, the main focus is on the material of the winding insulation. Lacquer and compound types of insulation of industrial electric motors, which are the main ones everywhere, have been analyzed. The analysis of the impregnating electrical insulating compositions of the stator windings of electric motors and the influence of ultrasound on them during dismantling of the windings of electric motors at different levels of influence of forcing factors: duration and power of ultrasonic action, concentration and temperature of the working solution. The applied mathematical software systems for calculation and modeling guarantee the reliability and rationality of the results of the experiments obtained during the work. A system of equations has been modeled and models of the effect of useful factors relative to each other have been constructed, the results obtained have been optimized and the optimal parameters of both varnish and compound insulation systems have been identified. The optimal parameters of the investigated types of insulation show encouraging results on many important points: duration, energy consumption, environmental friendliness.

Low-Cost Drive System for Electric Motors based on the IRAM Module

With the increasing use of equipment that demand electric drive systems, the need for new systems that meet requirements of compactness, versatility, safety and low cost has increased. The IRAM module is an electronic circuit that provides a driver for DC and AC motors, being extremely compact and presents high performance. In this context, this work contributes to the power electronics area, presenting a design and construction of a low cost drive system, based on IRAM module, developed for individual or simultaneous drive, up to two DC motors. To carry out the experiments, DC motors responsible for moving a welding robot, were used. Experimental results are presented to shown the feasibility of using this system.

Aircraft Electric Machines

Current trend in aviation is to increase efficiency of all the aircraft’s systems. This leads to a reduction of fuel consumption which has also positive effect on emissions. One possibility how to reach this aim is to replace hydraulic and pneumatic system with an electrical power system. Because many on-board electrical loads are in the form of electrical drives, the special attention is given to electric motors and their electronic speed controllers / power converters. Furthermore, electric motors suitable for traction/propulsion are presented. Moreover, the various types of starter/generators suitable for on-board utilisation are compared in the paper.

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.