The present paper deals with investigations concerning optical magnetic sensors. The most important advantage of sensors of this kind is their safety of service and insulating power. The insensitiveness of optical sensors to electromagnetic interference was discussed and experimentally investigated. The experimental investigations were concentrated on the adequate sensing fibre as well as on the sensor based on the bulk glass cylinder. The paper presents the results of magnetooptic tests of the elaborated magnetic field optical sensors and conclusions arise from them.

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Abstract. This paper presents investigation of methods for reducing light pulsation and plasma temperature inside a high intensity discharge (HID) lamp arc tube. Differences found in light emission of an arc tube plasma channel under different power supply methods are presented and discussed in this work. The novelty of the paper lies in systematical investigation of different power converter supply methods and demonstrating that it has a significant influence on plasma temperature in an arc tube. The tested lamp was powered by electronic ballasts controlled by different algorithms, which forced their current waveform. To compare the results, the authors performed measurements on a discharge lamp powered by a standard electromagnetic ballast. The investigation of plasma parameters is based on the optical spectroscopy method. It was shown that by using the appropriate current shape of a high switching frequency supply converter, the plasma temperature of an HID lamp can be reduced almost by half.Key words: plasma temperature, electronic ballast, electromagnetic ballast, lamp current, light flux, light pulsation, high intensity discharge lamp.Investigation of HID-lamp light emission differences for different power supply methods Therefore, authors decided to perform a research determining the aforementioned parameters of an HID lamp. Plasma theoryPlasma is a source of optical radiation. One of the methods used to examine this state of matter is optical spectroscopy. The spectrum of plasma radiation carries a lot of information about atoms or ions, such as the type of gases used in discharge lamps, and the conditions in which they are located. All the processes taking place in radial plasma can be interpreted as a transition between two different quantum energy states. Processes involving the radiation of electrons and atoms (or ions) occur when an electron moves in an electrical field from one charged particle to another, usually an ion. As a result of its interaction with this particle, part of the path of the electron is curved. The temperature inside the arc tube of a discharge lamp is the parameter that determines the appropriate spectral distribution of the energy emitted by the plasma discharge, and the corresponding luminous efficiency. In the radiation spectrum of an HID lamp, there are a number of lines, characteristic of excited atoms. The shape of the spectral line reveals the conditions (pressure and temperature) prevailing in the discharge lamp. Fig. 1 shows a view of luminous plasma in a cold arc tube, whereas Fig. 2 shows luminous plasma in a hot arc tube.

Measurement of the three components (axial, radial and azimuthal) of the magnetic field distribution (MFD) over the contact plate surface, having different slit shapes were made in a specially designed stand. These measurements were made for different azimuthal positions of both contacts, to analyze the influence of their position on the MFD. The results of measurements were presented and discussed.Selected contacts were installed in a dismountable vacuum chamber and switching tests were made at short circuit current from 1 kA to 16 kA. Switching arc was recorded by means of a high speed camera and the distribution of arc spots was observed.I.

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