Bogdan Miedzinski

Analytical and experimental investigations of reed contact bouncing

Studies of variations of the reed bounce-dynamics during operation are reported. The influence of such factors as temperature, contact current, gap discharge, as well as the energizing MMF value are investigated. Simplified mathematical models of the reed switch with one and two degrees of freedom, which take into account the magnetic effect of the current flow through the contact and the contact force variation with the gap length, are developed. >

Effect of a dynamic force compensation in a low voltage vacuum circuit breaker

The paper presents and discusses the investigated results of performance of a LV circuit breaker under short circuit conditions in a case when a contact dynamic repulsive force is self-compensated by the load.

Investigations of Reed Switch Dynamics and Discharge Phenomena When Switching Intermediate and Heavy Loads

Studies of reed switch dynamics and discharge phenomena when switching intermediate and large inductive currents are reported. The initial interactions of the reed dynamics and the dynamics of the electrical discharge in the contact gap during both opening and closing have been investigated. The investigations have been carried out using both oscilloscope studies and high speed photography of both dry and mercury-wetted reeds. Conclusions about the applications of reed switches for intermediate and large inductive currents are formulated.

The Actual State and Prospects of a High Power Electron Beam Technology for Metallic and Non-Metallic Compositions Used in Electric Contacts and Electrodes

In the paper the actual state and prospects of applicability of a high power electron beam technology for manufacturing metallic as well as nonmetallic composite materials mostly for electric contacts and electrodes are presented and discussed

Low frequency inductive heating of a rigid track during track laying

The possibility of applying low frequency current to heat railway rails is discussed. The temperature distribution in the rail as a function of the parameters of the heating inductor and its location is described. The investigation considers only slowly varying magnetic fields below 300 Hz. A mathematical model has been developed to analyze the heat transfer in the rail during the inductive heating. Conclusions about practical design rules for the use of inductive heating for track laying are formulated.

Bus Voltage Control Through 5 and 11 Level Voltage-Sourced Inverter Statcom

This paper describes and analyses methods of controlling bus voltage through 5 and 11 level voltage-sourced inverter STATCOM. The performance analysis is based on the level of voltage support, harmonics, and degree of dc-link voltage balancing of the inverter in constraining the bus voltage within acceptable limits, whereas the performance comparison relates cost and efficiency. An attempt is also made to describe the basic concept of VSI-STATCOM from the first principle. Superiority of the 11 level in controlling the bus voltage due to a faster response and greater voltage support is also documented. Furthermore the paper describes the switching methods mathematically and demonstrates the merits and drawbacks of inverters experimentally

Control of the Singular Points Location for Miniature Switches with Magnetically Driven Contacts

This paper presents and discusses usefulness and possibility of control of the singular points location of a driving magnetic field under as structure considerations as well as selection of energizing magnet systems for miniature electromagnetic switches. The sample results of theoretical analysis and experimental testing concern selected reed switches with normally open contacts as well as a developed miniature switch with a metallic ball contact. It must be noted that the switch with the contact performed by means of the metallic tiny ball can be effectively used both as a change-over switch as well as a detector of the energizing magnetic field distribution under designing and assembling of any electromagnetic contact device preferably with an increased degree of integration and miniaturization.

HDI PCB Rogowski Coils for Automated Electrical Power System Applications

This paper presents and discusses the results of analysis and experimental studies of the metrological characteristics of Rogowski coils made in high density interconnect printed circuit boards technology. The purpose of the research and analysis was to determine the possibility of their use in the metering units of automated electrical power systems. Particular emphasis is placed on the formation of the resonant characteristics as well as to provide suitable resistance to external interfering electromagnetic fields. This allows, inter alia, the use of Rogowski coils for detection of interfering transmissions power line communication high-frequency conductive currents. Based on the obtained results, conclusions and recommendations for practice are formulated.

Detection of the Trench Depth Based on a Differential Inertial Sensor Technology

The article proposes the use of a differential inertial sensors system for detection of the trench depth under operation. The inertial sensors are employed to detect a posture of the trencher and as a result to determine an angle difference through inertial sensors located on a vehicle (as a reference) and on the trencher arm. In this way, the undesirable, disturbing effects caused by unevenness of the field etc. are significantly reduced or even eliminated. The trench depth calculation procedure combines the angle difference and relative dimensions of the trencher structure. It is displayed on a monitor in real time. To perform a remote monitoring, the system is equipped with wireless transmission module using an upper-computer. To decrease data oscillation under operation, the calculated angles need to be filtered. Therefore, simulation based on Kalman filter in MATLAB was performed and found Q/R rate takes an important role in filtering and filtering test verified it. In field test, error rate between trench depth measured and detected is within 5 % what confirms the practical usefulness of the developed measuring system for the trench depth detection.DOI: http://dx.doi.org/10.5755/j01.eie.24.3.20973

Performance of active power filter in transient under non-linear loading

The paper analyses and examines the efficiency of operation of a newly developed active power filter (APF), based on a control algorithm using CPC theory when employed in transient under non-linear load conditions. The APF system is therefore, characterized and the selected results of its performance under laboratory testing are presented and discussed. Slowa kluczowe: praca aktywnego filtra mocy w stanach przejściowych.