M. Wołoszyn

Suitability study of hybrid model of electrodynamic actuator

This paper presents the proposal of the hybrid circumferential-field model of an electrodynamic actuator. The field model uses the inductor current as the input data which is obtained from the circumferential model or experimentally. The field model implemented using the FLUX program makes it possible to easily determine the pressure distribution acting on the disc. The results have been verified experimentally.

Effect of power frequency on the stress state of disc actuator

This paper presents the concept of determining the optimum frequency of coil supply in inductive-dynamic drive. As a criterion to obtain the sought frequency, the smallest value of reduced stress in the disc was assumed while maintaining the desired dynamics. The disc stress is determined on the basis of solution of vibrating thin plate equation. Magnetic pressure acting on the disc is obtained from a hybrid circumferentially-field model (CI-FI). The observations made during the experiment with the physical model of the actuator show that in some extreme cases the disc is clearly deformed, as evidenced by the oscillations of its center (Fig. 2). Hence, it is necessary to determine the stress state of the disc, due to the possibility of not only elastic, but even plastic deformation of the disc. Even a slight deformation of the disc is unacceptable from the standpoint of repeatability of drive work in the hybrid circuit breaker (6). Therefore, to determine the stress state of the disc, a mechanical model for a circular plate energized by electrodynamic force, has been built. The force was calculatedin the program realising CI-FI modelpresented in the accompanying article (5). Electrodynamic actuators consist of two main parts: a coil supplied with capacitor banks and a movable disc. The disc in a hybrid circuit design solutions is also a movable contact (Fig. 1). Drive project is made individually depending on the properties of the circuit breaker to which it is to be used. It is based on the selection of actuator parameters such as the dimensions of the disc and the coil and the number of turns, and also the capacitance and initial voltage capacitors. The selection criteria for these parameters are usually determined by the set dynamics of the disc, that is contact (disc) must achieve sufficient distance in a specified time. This criterion is met by a suitable choice of initial energy of the capacitor in relation to the mass of the disc. By changing the dimensions of the disc, e.g. by reducing the thickness, one can improve its dynamics, but it should be kept in mind that its deflection can then grow. On the other hand, the initial energy of the capacitors depends on the voltage and capacitance. The change of capacitance will change the frequency of the transient coil current and hence it will change the force frequency that forms as a result of the electrodynamic interaction.

Analysis of ship's magnetic field with consideration of inner ferromagnetic devices

This paper presents computer simulations of ships magnetic signatures. The influence of ships inner ferromagnetic devices on the signature was presented. The magnetic fields of the ships model were calculated in Opera 3D 18R2. The model was built from thin plates. The new, thin plate boundary condition [1] was introduced on all ships surfaces.

Analysis of the influence of ferromagnetic contaminations in plastics on the measurements of disturbances of magnetic field of the Earth

Plastics can be contaminated with small particles or filings with ferromagnetic properties. These contaminations cause significantndisturbances in the magnetic field in the case of taking measurements of very low magnetic fields. The analysis of the influence of contaminatednplastics on magnetic measurements is presented in this paper.

Simulation of ship's deperming process using Opera 3D

This paper presents computer simulations of ships deperming. The ferromagnetic-hulled ship or submarine develops a magnetic signature due to magneto-mechanical interaction with the Earth magnetic field. There are several methods of ships deperming [1,2]. The deperming method with system of coils lying on the seabed is presented in this paper. The deperming process was calculated in Opera 3D 18R2.

Analysis of resistive and inductive heating of railway turnouts

Elektryczne ogrzewanie rozjazdow kolejowych jest istotnym problemem technicznym i ekonomicznym. Z tych wzgledow potrzebne sąnbadania w celu optymalizacji systemu ogrzewania rozjazdow kolejowych. W artykule przedstawiono analize porownawczą strat energii podczasnogrzewania rozjazdow kolejowych z wykorzystaniem dwoch roznych metod. Analiza ogrzewania rozjazdow przeprowadzono w programie ANSYS.(Analiza oporowego i indukcyjnego nagrzewania rozjazdow kolejowych)

Magnetic and infrared thermography methods in detection of antipersonnel landmines

Purpose – The purpose of this paper is to present two methods of detection for landmines with minimal metal content. Design/methodology/approach – First, two methods of landmine detection are presented: magnetic and infrared with microwave heating. For each method the numerical algorithm of an object’s position and properties determination are presented. Furthermore, the experimental results of several landmines detection using both methods are presented. Findings – It is possible to detect the landmines with minimal metal content using both magnetic and infrared methods. It is also possible to determine the detected objects’ exact position and properties using developed numerical algorithms. Originality/value – The idea of using the magnetic method to detect the plastic landmines is, to the best knowledge of the authors, new. For both methods, the numerical algorithms of objects’ parameters determination are original.

Compensation of magnetic disturbances caused by sensors in a differential magnetometric system

Study of low magnetic fields necessitates the use of precision magnetometers working in a differential system. Minimization of this error is a substantial issue in the case of magnetometers working in a differential system on a mobile platform. The compensation method of heading error consists in taking measurements of changes in magnetic induction with the use of the tested magnetometer for various locations of the sensor in relation to the vector of the Earth’s magnetic flux density. Streszczenie. Badania bardzo słabych pól magnetycznych wymagają zastosowania precyzyjnych magnetometrów pracujących w układzie różnicowym. W pracy opisano dwie metody kompensacji tego błędu. Metoda kompensacji błędu kierunkowego polega na wykonywaniu pomiarów zmian indukcji magnetycznej przy zastosowaniu badanego magnetometru dla różnych położeń czujnika w stosunku do wektora indukcji magnetycznej Ziemi. Znając zależność tego błędu w funkcji położenia czujnika można wpływ błędu kierunkowego skutecznie zminimalizować. (Kompensacja zaburzeń magnetycznych wywołanych przez czujniki różnicowego systemu pomiarowego)

Magnetic disturbances caused by magnetic contamination of plastics

In the study of low magnetic fields precision magnetometers working in a differential system are used. Two optically pumped magnetometers working in a differential system allow for precise measuring of disturbances in the magnetic field. In order to attain high accuracy of magnetic field measurement, it is necessary to use appropriate materials for the construction of a magnetometric system, particularly of those located closely to the magnetometric sensor. These materials can disturb the magnetic field. Streszczenie. W pomiarach słabych pól magnetycznych stosowane są precyzyjne magnetometry pracujące w układzie różnicowym. Dwa magnetometry pompowane optycznie pracujące w układzie różnicowym pozwalają na dokładne pomiary zakłóceń pola magnetycznego Ziemi. W celu osiągnięcia dużej dokładności pomiaru pola magnetycznego konieczne jest stosowanie odpowiednich materiałów do budowy systemu magnetometrycznego, szczególnie tych znajdujących się blisko czujnika magnetycznego. Materiały te mogą zaburzać pole magnetyczne. (Zaburzenia pola magnetycznego wywołane przez zanieczyszczenia magnetyczne tworzyw sztucznych)