In the Baltic countries interest to the renewable energy is growing. Government support and availability of large unpopulated areas on the coast makes attractive use of these lands for the placement of large wind power plants (WPP). For successful implementation of planned projects reliable information about distribution of the resource of wind energy is needed. Researches in this area are carried out by collaboration IPE with VUC. The paper presents the results of years-long observations on the density fluctuations of wind energy at heights of 10 to 60 m in the area in the Baltic Sea coast in the north and the southwest of Latvia. The velocity observations from 2004 t ill 2010 years have been obtained by measurements complex of the LOGGER 9200 Symphonie type. The results presented in the form of tables, bar charts and graphs. The graphs of seasonal fluctuations of wind speed have been obtained for the heights up to 60 m by measurements over the period of 2007-2010. The histograms have been composed for the relative frequency of repetition of wind speed. The wind speed distribution on heights up to 60 m was analysed and coefficients of approximating functions for the two areas with different terrain types were calculated. Extrapolation results of the distribution curves of wind velocity and density mean values on heights up to 150 m were shown.
Governmental support and the availability of large unpopulated areas on the coasts of the Baltic countries make attractive the use of these lands for siting large wind power plants (WPP). Studies in the area of wind energy resource distribution are carried out by the IPE with collaboration with the VeU. The observations of wind speed were made using the measuring complex NRG LOGGER 9200 Symphonie. The results of long-term observations on the wind energy density fluctuations at heights of 10 to 60 m in the area on the Baltic Sea coast of Latvia are presented in the form of tables, bar charts and graphs. The wind speed distribution is analysed. The coefficients of approximating functions for two areas of different terrain types have been calculated, and extrapolation results for the distribution curves of wind speed and energy density obtained. The acoustic noise level distribution around a planned WPP has been modelled.
In the paper, the possibilities to apply synchronous brushless motors in the electric hand tools are considered. The potential of such motors is estimated in a wide range of characteristics. In particular, estimation is made for the electric hand plane with a synchronous motor having outer rotor and excitation from permanent magnets.
The paper presents an overview of brushless electric motors used in hand electric tools and household appliances. Analysis of the motor types has shown that synchronous reluctance motors are the most reliable for lowpower drives of such tools and appliances due to their simple design, long service life and low cost of production. Solutions are proposed for significant decrease in the quadrature-axis magnetic flux of the synchronous reluctance motor. The motors are shown to develop the specific electromagnetic torque up to 0.35÷0.4 Nm/kg.
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