The paper deals with the problems in the operation of non-linear loads, causing distortions in the sinewaves of voltages and currents. There is currently increasing use of variable frequency drives (frequency inverters) that drive electric motors and are such loads. The experimental results cover multiple measurements of voltages and currents harmonic components and the calculated values of the total harmonic distortion coefficients of voltage and current for each of the phases, supplying different loads. An analysis of the results obtained has been done and specific conclusions have been pointed out on the basis of the measurements carried out.
Author: Rachev S.
TRANSPORT TECHNICS. INVESTIGATION OF ELEMENTS. RELIABILITY
Paper deals with specifics of converting a conventional car into an electric one. The main stages of the conversion process are dealt concise but thorough. The findings are the basis for launching a large scale project with the necessary duration and financing, as a result of carrying out the necessary development activities and experiments will proceed to the development of a prototype, which will ultimately be realized. The overall focus is on research and application in the students’ learning process.
DOMINANT TECHNOLOGIES IN “INDUSTRY 4.0”
ANALYSIS OF OPERATING MODES AND ENERGY EFFICIENT PRACTICES DURING THE OPERATION OF INDUSTRIAL INDUCTION FURNACES WITH NETWORK AND MIDDLE FREQUENCY
Among the main problems of the induction furnaces are the clearly manifested worsened power factor during operation, the asymmetry, the deflection and the variance of the supply voltage in their power supply. Induction furnaces in all their operating modes are a non-linear load with significant and varying consumption of active and reactive energy. Compensation devices are set for the heaviest mode of operation – metal melting. There remains a question of the limits of the low inherent power factor for individual regimes, the size of the penalties for this on an annual basis, and the potential energy saving measures taking into account the possibilities of waste heat utilization. In this connection, the task of implementation of modern optimal management according to predefined criteria is current.
In the case of energy-efficient drives with induction motors, the tendency to implement optimally designed motors, combined with intelligent control, incorporating an integrated monitoring and diagnostics system, is becoming increasingly important. Induction motors in industrial systems operate with frequent starting, dynamic loads and sometimes unbalance of supply voltage. In order to maintain an optimal operating condition, reduce the number of failures and build up an optimal repair and maintenance system, it is important to have an advanced monitoring system coupled with fault identification techniques. The behavior of optimally designed three-phase induction motors designed to operate integrated into hydraulic units with continuous duty operating mode is considered
STUDY OF THE INFLUENCE OF SUPPLY VOLTAGE ON THE DYNAMIC BEHAVIOR OF INDUCTION MOTOR LOW VOLTAGE DRIVE
Paper deals with the dynamic behavior of pump unit electric drive. The electric motor, subject of development, is a new standard efficiency induction motor with squirrel cage rotor, designed to operate in continuous operation. The determination of operating characteristics of induction motor in dynamic modes is necessary to establish the properties of the machine in specific conditions. In some industrial areas can occur very often sags with a depth of between 10% and 15% of the rated voltage as a result of switching electrical loads on systems of users. As a result of simulation studies the influences of the supply voltage and total torque of inertia of the electric drive have been assessed on arising impact torques and currents and electric energy losses of electric drive for pump unit. The results obtained are in addition to experimental studies of the same motor. Some of the study results have been presented graphically. An analysis and conclusions from the results obtained have been done
STUDY OF RESISTING MOMENT INFLUENCE ON OPERATION OF HIGH-VOLTAGE INDUCTION MOTOR PUMP ELECTRIC DRIVE
Paper deals with dynamic behavior of powerful electric drive for pump unit. The practical application of these electric drives is diverse. In industry they drive a wide range of mechanisms connected to them. Some of them are pumps with varying degrees of security for thermal or nuclear power plants. The nature of the flow of transient processes in the electrical machine often determines the behavior of the entire system, an element of which is the machine. As a result the values of the energy losses components in the induction motor have been obtained according to different values of initial resisting moment. Some of the study results have been presented graphically. An analysis has been made and conclusions from the results obtained have been done.
SOCIETY & ”INDUSTRY 4.0”
The paper considers the results of desk and field research on the strengths and weakness of young and older employees carried out in eight EU countries. In addition, it outlines the competence gaps of public sector employees 30- and 50+. Furthermore, the paper presents an alternative learning path that will improve the competences of the employees in the public sector making an attempt to bridge the intergenerational gap thus fostering their competitiveness on the labour market. Conclusions about the effectiveness of the proposed learning path are drawn.