QuarterlyIssue 2 (214)
Scientific Committee
CONTENTS
Foreword
- Bogusław GRZESIK, Krzysztof BODZEK: Simulation of power losses of linear modular high freqency transformer
- Jan SZAJNAR, Mariusz STĘPIEŃ, Bogusław GRZESIK: Thermal and electromagnetic field analysis of a cast iron continous casting process
- Janusz WALCZAK, Rafał STĘPIEŃ: Microprocessor based white noise generator
- Krzysztof MUSIOŁ, Grzegorz POPEK, Tadeusz SKUBIS: Influence of the residual parameters of the impedance comparator bridge on the inductance standard comparison results
- Łukasz PIĄTEK: Algorithm for finding cuts in undirected graph
- Mariusz STĘPIEŃ, Bogusław GRZESIK: Characteristics of new magnetic materials in LN2 for HTS transformers
- Michał LEWANDOWSKI, Marcin MACIĄŻEK, Marian PASKO: Application of Matlab/Simulink package to optimization of harmonic current flow in selected fragments of electrical power grid
- Piotr ZIENTEK, Roman NIESTRÓJ: Shaft voltages in high power induction motors
- Radosław JEŻ, Mariusz STĘPIEŃ, Bogusław GRZESIK: Analysis of the magnetic field in HTS toroidal transformer
- Tadeusz TOPÓR-KAMIŃSKI, Beata KRUPANEK: Design of computer networks including requirements for internet services using OPNET MODELER
- Tomasz MNICH: Thermal protection of induction motors base of use of equivalent thermal diagrams
Bogusław GRZESIK, Krzysztof BODZEK
Katedra Energoelektroniki Napędu Elektrycznego i Robotyki, Politechnika Śląska w Gliwicach
SIMULATION OF POWER LOSSES OF LINEAR MODULAR HIGH FREQENCY TRANSFORMER
Summary. The paper is devoted to the 2D-3D hybrid model of field analysis of high frequency linear modular transformer power losses. The harmonic electromagnetic field is analysed by means of the finite element method (FEM). The proposed model consists of two parts 2D and 3D that enable power losses calculation in linear part and in more complex part embracing winding interconnections and leads, respectively. The overall power losses are the relevant sum of power losses calculated with 2D and 3D model. The power losses calculated by means of FEM are in good agreement with those measured.
Jan SZAJNAR
Katedra Odlewnictwa, Politechnika Śląska w Gliwicach
Mariusz STĘPIEŃ, Bogusław GRZESIK
Katedra Energoelektroniki, Napędu Elektrycznego i Robotyki, Politechnika Śląska w Gliwicach
THERMAL AND ELECTROMAGNETIC FIELD ANALYSIS OF A CAST IRON CONTINOUS CASTING PROCESS
Summary. The aim of the paper is to determine crystallization zone and forces generated by the electromagnetic field acting on cast iron during crystallization in continuous casting process. Proper distributions of temperature gradients are needed during continuous casting process to receive the proper cast iron structure. Analysis is carried out using the finite element method (FEM) and ANSYS software. The thermal and electromagnetic analysis of force interactions on cast iron was carried out using two different independent computational models. The crystallization zone and distribution of magnetic forces in cast iron were determined.
Janusz WALCZAK, Rafał STĘPIEŃ
Instytut Elektrotechniki i Informatyki, Politechnika Śląska w Gliwicach
MICROPROCESSOR BASED WHITE NOISE GENERATOR
Summary. This paper describes a microprocessor based white noise generator. The noise generation is realised by program implementation of the LFSR register with a dynamically changed feedback polynomial. The model circuit was based on the AVR ATMEGA16 microprocessor. Selected results of statistical investigations are given.
Krzysztof MUSIOŁ, Grzegorz POPEK, Tadeusz SKUBIS
Instytut Metrologii, Elektroniki i Automatyki, Politechnika Śląska w Gliwicach
INFLUENCE OF THE RESIDUAL PARAMETERS OF THE IMPEDANCE COMPARATOR BRIDGE ON THE INDUCTANCE STANDARD COMPARISON RESULTS
Summary. Influence of residual parameters of an impedance comparator bridge measuring circuit on the inductance standard comparison accuracy is analysed in the paper. Simulation investigations of the influence of unequal capacitances of connecting cables on the impedance components of the GR1482 standard inductors were performed. The results obtained by reversion of the standards were compared with those obtained from the procedure without reversion. The correction parameters of the KWL5 bridge were calculated based on the results obtained for 10 H inductance standards for different combination of their connection with the comparator bridge.
Łukasz PIĄTEK
Instytut Informatyki, Wydział Elektryczny, Politechnika Częstochowska
ALGORITHM FOR FINDING CUTS IN UNDIRECTED GRAPH
Summary. Computing the reliability of a sensor and actor network is a complex task. The complicated network structure causes that it is impossible to work out a direct computation method. To compute the network reliability, there is proposed a method consisting in construction of a parallel-series structure of equivalent reliability with use of graph cuts of the sensor and actor network. In the paper it is shown how the number and order of elements in the considered cuts used for computations influence the accuracy of reliability calculations.
Mariusz STĘPIEŃ, Bogusław GRZESIK
Politechnika Śląska, Katedra Energoelektroniki, Napędu Elektrycznego i Robotyki
CHARACTERISTICS OF NEW MAGNETIC MATERIALS IN LN2 FOR HTS TRANSFORMERS
Summary. The paper presents B-H characteristics of three amorphous magnetic materials measured at LN2 temperature and at room temperature. The proposed application of the tested materials are magnetic cores of HTS transformers. The characteristics were measured at 50 Hz with use of a Remacomp® meter and at higher frequencies when supplying the coil and magnetic core by a DE inverter. The measurement results obtained at higher frequencies are more precise because of higher level of power losses. The results confirm good properties of the investigated materials for the proposed application.
Michał LEWANDOWSKI, Marcin MACIĄŻEK, Marian PASKO
Instytut Elektrotechniki i Informatyki, Politechnika Śląska
APPLICATION OF MATLAB/SIMULINK PACKAGE TO OPTIMIZATION OF HARMONIC CURRENT FLOW IN SELECTED FRAGMENTS OF ELECTRICAL POWER GRID
Summary. The paper presents three methods of Matlab/Simulink application to harmonic current flow simulation in selected fragments of an electrical power grid. The first two methods are based on SimPowerSystems and PSAT toolboxes. The third one involves direct implementation of the system frequency model in Matlab language. For the all presented methods it is possible to use Optimization Toolbox algorithms to find the optimal placement of harmonic compensators in the analysed system.
Piotr ZIENTEK, Roman NIESTRÓJ
Instytut Elektrotechniki i Informatyki, Politechnika Śląska w Gliwicach
SHAFT VOLTAGES IN HIGH POWER INDUCTION MOTORS
Summary. The paper presents results of investigations aimed at bearing faults detection in high power induction motors. Different kinds of bearing damages arising in the considered motors are shown. The causes of occurring the shaft voltages and bearing currents are given as well. In Section 5 there is presented influence of the supply voltage unbalance on the shaft voltage values. The conclusions drawn from the laboratory tests are presented in Section 7.
Radosław JEŻ, Mariusz STĘPIEŃ, Bogusław GRZESIK
Katedra Energoelektroniki, Napędu Elektrycznego i Robotyki, Politechnika Śląska w Gliwicach
ANALYSIS OF THE MAGNETIC FIELD IN HTS TOROIDAL TRANSFORMER
Summary. The 3D, FEM analysis of properties of the HTS toroidal transformer is described in the paper. It is a 50 Hz transformer with cold magnetic core (LN2). Six variants of the transformer were investigated. The distribution of magnetic field density and power losses was analysed. There were also calculated the primary voltage and current, the overall power losses, the output power and power density. The first three variants have parallel windings, while the rest of them have perpendicular ones. One variant, from among the six analysed, shows higher power density than that reported in the literature.
Tadeusz TOPÓR-KAMIŃSKI, Beata KRUPANEK
Instytut Metrologii, Elektroniki i Automatyki, Politechnika Śląska w Gliwicach
DESIGN OF COMPUTER NETWORKS INCLUDING REQUIREMENTS FOR INTERNET SERVICES USING OPNET MODELER
Summary. The aim of the paper is to provide a basis for designing computer networks, taking into account the users workstation location and type of services for users and by users. Today's computer networks are the basis of all communication systems which currently affect the level of the country's economy, security and quality of life. An effective ICT network supports virtually work of every modern institution: large company, small business, office, school, hospital. The same transmission medium is often used to transmit various types of information: computer data, voice and image. The modern approach requires specification of the network services to implement the network to their customers, then choice of the most appropriate operating system, choice of the communication protocol, choice of the media outlet, design of application of active devices, design of couplings with public networks, cabling project.
TOMASZ Mnich
Instytut Elektrotechniki i Informatyki, Politechnika Śląska w Gliwicach
THERMAL PROTECTION OF INDUCTION MOTORS BASE OF USE OF EQUIVALENT THERMAL DIAGRAMS
Summary. The paper presents use of the method of thermal equivalent diagrams for detecting thermal hazards of induction motors. The author presents the principle of operation of the thermal protection Sepam 1000 and compares it with the method for induction motor protection based on the thermal equivalent diagram. The results of computer calculations and measurements are given as well.