The paper aims at presenting the results from numerical studies of the heating in a low-voltage power distribution block at transient mode. For this purpose, a 3D computer model of the power distribution block in COMSOL software package has been developed. Coupled electric field – thermal field – fluid mechanics problem has been solved taking into account the constructive peculiarities of the block. The thermodynamic processes within the volume of the terminal block have been taken into account. The heat transfer from the surface of the power distribution block and the current-carrying elements to the surrounding environment through radiation and convection have also been accounted for. Results have been obtained for the heating of the power distribution block in transient mode under different current loads. The comparison between computed and experimental results shows good agreement. The developed model can be used for prediction of the thermal behavior of the power distribution block, as well as for estimating the maximal current that does not lead to a temperature rise above the standard limited value.

Nowadays, due to the rapid changes in power systems driven by the development of new power sources, the requirements for devices providing switching from one power source to another are also constantly changing. For this reason, the current work presents the development of an open source automatic transfer switch (ATS) device that has advanced capabilities such as switching between three different sources, energy monitoring, and remote access. By modifying only the software, the proposed device can be used in other applications such as additional smart protection in a three-phase system or as a measurement system.

One of the most important parameters for the normal operation of a transformer is its level of heating. Transformer heating significantly determines the reliability and service life of the transformer. The temperature distribution in the active parts of the transformer during its operation depends on the current load and the cooling conditions of the transformer. The influence of the cooling conditions on the heating of the transformer is investigated in this paper through a developed 3D computer model of an oil-immersed transformer. Results have been obtained on the effect of the oil velocity and oil temperature on the transformer thermal field.

This paper presents a study of thermal processes and time-current characteristics of a high-power low-voltage fuse at normal and increased contact resistance. Experimental and numerical studies have been performed. The experimental studies have been carried out by means of an experimental setup, especially developed for the purpose. Temperature measurement has been realised both by a contact thermometer and by a thermovision camera. The finite element method has been used in the numerical study. A computer model of the fuse has been developed in the software product COMSOL. The model reads the thermal processes in the fuse, as well as the heat transfer to the environment, which occurs by radiation and convection. Results about the influence of the contact resistance on the fuse heating and its time-current characteristic have been obtained. The obtained experimental and numerical results have been compared.

This paper presents a numerical study of the heating of a high-power low-voltage fuse considering the influence of the thermal flows propagating along the connecting conductors. These thermal flows are generated by losses both in the conductors and in the current-carrying circuits of the switchgears connected to the electrical circuit of the fuse, thus being external losses for the fuse. The numerical results have been obtained by means of a computer model developed in COMSOL program with taking into account the heat transfer from the fuse surface to the environment by radiation and convection. Results concerning the influence of the external losses and the lengths of the connecting conductors on the thermal field in the fuse have been obtained.

The paper presents optimization of a newly developed hybrid electromagnetic system with magnetic flux modulation, for which patent application has been submitted. The efficiency of the system has been taken as objective function. The optimization factors include both geometrical and electrical parameters. Finite element method and three-dimensional coupled time-dependent electromagnetic field-electrical circuit analysis has been used for the solution of the forward problem. Response surface methodology and sequential linear programming are employed for the optimization.

The present paper considers a possible application of the increasingly popular open-source systems as a complete solution (hardware-software and communication protocol) in electrical engineering work. The main goal of the developed open-source system is to use it to monitor remotely certain parameters in low voltage electrical panels. Based on the collected data from the different sensors and after the respective analysis, the system has the ability to automatically execute pre- set management scenarios in critical situations. To proof the concept, a prototype of the system is built and several experimental measurements are carried out.

This paper presents a study of the heating of a high-power low-voltage fuse by means of a thermal imaging camera. An experimental setup has been developed for the purpose of the study. The tests have been conducted at rated and higher current loads for the fuse-link, as well as at normal and increased contact resistances between the knife contacts and the base of the fuse. Results are given for the temperature distribution along the surface of the knife contacts and the fuse body in transient thermal mode of the fuse. The influence of the current and the contact resistance on the fuse heating and its actuation time has also been considered.

The use of open-source software and hardware systems in engineering applications is constantly growing. In this paper, an open-source system for controlling hybrid electromagnetic system with magnetic modulation is developed and tested. Some results when powering the tested device with pulses of different frequency are shown.

Introduction. Nowadays, the accelerated development of materials and technologies and the finding of new ones is a prerequisite for the improvement of well-known electromagnetic constructions used in various devices, as well as for the development of new ones. New construction of hybrid electromagnetic system with magnetic flux modulation (HEMSMM) is studied. The construction is composed of: ferromagnetic frame with air gaps, input and output coils and permanent magnets. Two input coils connected to the pulsed power supply are used to change the path of the generated by the permanent magnets constant magnetic flux. Input pulses with different shapes are applied to the input coils and signals in the output coils are obtained and compared. The main purpose of the work is to find the shape of the input pulses which leads to higher output power in comparison with the other shapes. Methods. Finite element method and COMSOL software is used for computer modelling of the proposed construction, where coupled electromagnetic field – electric circuit analysis is carried out. Results. A mathematical and numerical 3D model of new HEMSMM construction is realised and studied. The model allows to calculate and compare power efficiency of the studied device, when input pulses with different shapes are applied. Practical value. The developed computer model enables the study of the HEMSMM and other electromagnetic devices at different operating modes. It can be further improved and used in the search for optimal parameters of a particular electromagnetic device.

The paper presents an approach to investigate the effect of different design parameters on the static “force-travel” characteristics and the magnetic field distribution of patented variants of an electromagnetic module for a Braille screen

Persons with visual impairments have difficulties to work with graphical computer interface, such as Windows icons. Also they do not have access to objects of cultural and historical heritage such as paintings, tapestries, icons, etc. The chapter presents an approach for providing visual Braille services by 3D digitization of planar or spatial objects using a graphical Braille display and/or tactile graphical tiles, supplemented with Braille annotations. A solution involving 3D touch by tactile reading of exhibits in a version accessible and affordable to visual impaired people is presented. Different existing devices, called Braille displays are described. Our technology for graphical Braille display is on the base of linear electromagnetic micro drives is shown. The presented ‘InterCriteria’ decision making approach is based on two fundamental concepts: intuitionistic fuzzy sets and index matrices. A comparative analysis of hybrid electromagnetic systems on the base of InterCriteria Analysis approach is given.

Experimental study of a prototype of hybrid electromagnetic system with magnetic flux modulation is carried out with specially assembled control and measurement circuits. Also, software algorithm and computer graphical interface for controlling of the system and for visualisation of the achieved results have been developed. Results are obtained for the current through the coils and for the changes of the magnetic flux. Two different measurement sensors are used in order to verify the accuracy of the results for the current through the coils,

The paper presents a parametric study of an electrothermal oscillator based on Shape Memory Alloy. The operating principle of the oscillator is established on a heated by electric current Shape Memory Alloy wire, mounted with a pre-tension between the free ends of two symmetrically placed cantilever beams. The effect of crystallographic changes in the wire due to heating leads to the generation of mechanical and electrical vibrations. Parametric studies were conducted to investigate the influence of the input parameters on the system output characteristics.

The paper presents the results from a study of a capacitor bank with detuned reactor for power factor correction in a three-phase low voltage network. The effect of the high harmonics in the network, as well as the influence of the inductance of the detuned reactor on the operational parameters of the three-phase capacitor bank have been studied by means of a computer model, synthesized in Matlab/Simulink. The parameters of the network have been taken into account. The studies have been performed at the following values of capacitive power of the capacitor bank: 10kVAr, 30kVAr, 50kVAr and 60kVAr. Conclusions have been made and recommendations given concerning the choice of a detuned reactor for power factor correction devices.

Efficiency of two electromagnetic systems is compared - E-core transformer and hybrid electromagnetic system with magnetic modulation. The latter is created by adding permanent magnet to the construction of the E-core transformer. Coupled electric circuit - electromagnetic field analysis is carried out using FEM based software. The results show higher efficiency of the hybrid system.

In this paper, the results from a study of the heating in a high power low voltage fuse are presented. The experimental tests have been conducted with an especially developed experimental installation. Thermocouples of K-type have been used for measuring the temperature. The numerical study has been done with computer model of the fuse made in COMSOL software. Coupled electric-thermal problem is solved. The model takes into account both the heat transfer from the surface of the fuse toward the environment by radiation and convection, and the heat flow, propagating from the current-carrying elements of the fuse toward the connecting conductors. A comparison between the obtained numerical and experimental results, concerning the heating of the fuse has been drawn.

This paper considers the heating in a closed low-voltage power distribution block by simulation and experiment. For the simulation, Coupled problem electric field-thermal field-fluid mechanics has been solved by means of a computer model, developed in the COMSOL software package. The model takes into account both the thermodynamic processes and the heat exchange through radiation in the volume of the power distribution block, and the heat exchange through radiation and convection towards the environment. Experimental studies have been carried out by means of specially developed computer-controlled experimental setup. Comparison has been made between the obtained numerical and experimental results, related to the heating in the distribution block, and good agreement has been achieved.

Abstract The paper presents an experimental setup and a method for determining the contact resistance between busbars at a given contact force. Experiments have been conducted by means of an experimental setup, developed for the purpose of studying the influence of the contact force on the contact resistance between busbars with cross-sectional area of 60x6 mm. The study has been performed for two types of bolted connections, complying with DIN 43673, which have been studied for both copper and aluminum busbars.