In this work, the electromotive force (EMF) near a permanent magnet heating cylinder was determined using a practical test bench. The aim is to elaborate three-dimensional analytical calculation capable of predicting accurately the same electromagnetic quantities by calculating the induced EMF in the presence of an inductive sensor. The analytical approach is obtained from developing mathematical integrals using the Coulombian approach to permanent magnets. In this approach, rotations are considered by Euler’s transformations matrices permitting the calculation of all permanent magnets flux densities contributions at the same points in the surrounding free space. These points, part of a uniform rectangular grid of the active EMF sensor surface, are used to compute the EMF by Faraday’s law. The validation results between experimental and simulated ones confirm the robustness and the efficiency of the proposed analytical approach.

This study addresses the problem of magnetic field emission produced by the laptop computers. Although, the magnetic field is spread over the entire frequency spectrum, the most dangerous part of it to the laptop users is the frequency range from 50 to 500 Hz, commonly called the extremely low frequency magnetic field. In this frequency region the magnetic field is characterized by high peak values. To examine the influence of laptop’s magnetic field emission in the office, a specific experiment is proposed. It includes the measurement of the magnetic field at six laptop’s positions, which are in close contact to its user. The results obtained from ten different laptop computers show the extremely high emission at some positions, which are dependent on the power dissipation or bad ergonomics. Eventually, the experiment extracts these dangerous positions of magnetic field emission and suggests possible solutions.

Due to rapid development of wireless systems and future implementation of the 5G system, it is necessary to increase number of the stations and/or number of radio emissions in current and new mobile service frequency bands. For each of the new or modified radio installation in Poland the Electromagnetic Field (EMF) strength levels has to be evaluated and measured/validated in accordance with allowable limits. In the paper the model of estimation of total EMF levels coming from mobile base stations radio emissions to be used for estimation of the whole country territory EMF levels is proposed. Results of preliminary analysis were also shown on practical examples. The model presented in the paper can be used for initial finding of possible places where exist the risk of exceedance of the maximum exposure limits and for analysis of potential radio network development taking into account current regulatory limits. The model will be used in computerized system SI2PEM which is developing in Poland for EMF levels controlling and validation purposes.

The electromagnetic field (EMF) is an environmental factor affecting living organisms. The aim of this study was to demonstrate the effect of an extremely low frequency electro- magnetic field (ELF-EMF) on selected chemical components of the honeybee (Apis mellifera L.) using Fourier Transform Infrared (FTIR) spectroscopy. The FTIR method provides information on the chemical structure of compounds through identification and analysis of functional groups. The honeybees were treated with EMF at a frequency of 50 Hz and magnetic induction of 1.6 mT for 2, 6, 12, 24 and 48 hours. Analysis of FTIR spectra showed that EMF exposure longer than 2 hours induced changes in the structure of chemical compounds, especially in the IR region corresponding to DNA, RNA, phospholipids and protein vibrations, compared to control samples (bees not EMF treated). The results confirm the effect of EMF on bees depending on the duration of exposure.

Thermodynamic assessment of the phase stability of the solid solutions of superionic alloys of the Ag3SBr1-xClx(I) system in the concentration range 0 ≤ x ≤ 0.4 and temperature range 370–395 K was performed. Partial functions of silver in the alloys of solid solution were used as the thermodynamic parameters. The values of partial thermodynamic functions were obtained with the use of the electromotive force method. Potential-forming processes were performed in electrochemical cells. Linear dependence of the electromotive force of cells on temperature was used to calculate the partial thermodynamic functions of silver in the alloys. The serpentine-like shape of the thermodynamic functions in the concentration range 0–4 is an evidence of the metastable state of solid solution. The equilibrium phase state of the alloys is predicted to feature the formation of the intermediate phase Ag3SBr0.76Cl0.24, and the solubility gap of the solid solution ranges of Ag3SBr0.76Cl0.24and Ag3SBr.

Comparison of the electromagnetic performance of a flux-switching permanent magnet (PM) machine having two separate stators as well as different winding topologies is investigated in this paper. Different stator and rotor pole combinations of these machines are also considered. The analysis includes the open-circuit and on-load characteristics of the analyzed machines. It is observed that, the largest fundamental values of electromagnetic torque, for each winding topology, is seen in the 11-rotor-pole and 10-rotor-pole machines having alternate- and all-pole-wound configurations, respectively. Moreover, significant ripple is observed in the waveforms of the even-number rotor pole machines compared to their corresponding odd-number rotor pole counterparts. Overall, the alternate-pole-wound machines essentially have larger torque-density than their equivalent all-pole-wound ones. The investigated machine is also tested for validation.

In this paper the mathematical model of the brushless DC motor (BLDCM) with a double 3-phase stator winding is analysed. Both the 3-phase windings are mutually displaced by 30 electrical degree. Special care has been sacrificed to influence of higher harmonics of induced electromotive forces (EMF) on electromagnetic torque and zero sequence voltages that may be used for sensorless control. The mathematical model has been presented in natural variables and, after transformation to symmetrical components, in a vector form. This allows, from one side, for formulating the equivalent circuit suitable for circuit oriented simulators (e.g.: Spice, SimPowerSystems of Simulink) and, from the other point of view, for analysis of higher harmonics influence on control possibilities. These considerations have been illustrated with some results of four quadrant operation obtainded due to simulation at automatic control.

This paper presents a simplified modeling, simulation and Experimental analysis of permanent magnet brushless dc motors (PMBLDC) for sensorless operation. This model provides a mechanism for monitoring and controlling of voltage, current, Speer and torque. The sensorless scheme employs direct back emf based zero crossing detection for controlling the dynamic characteristics.