Aspects Regarding Operation Characteristics of Brush-less Direct Current Motors

The researches regarding optimization in the area of electrical machines, include with priority the problem of the energy efficiency, by increasing the efficiency and the power factor. The objectives followed in this paper are the analysis of the operation characteristics, the fabrication and exploitation cost for brushless direct current motors rated at very low power. The utilization of permanent magnets having high specific energy in the construction of these motors influenced the machine performances, the cost and exploitation price. The research carried out aims at reducing the electrical energy consumption in exploitation by optimally dimensioning the permanent magnets. The last part of the paper compares two motors (brushless direct current motor and synchronous motor), both of them having permanent magnets, the same rated data, the same electromagnetic stresses and the same main constructive dimensions. It results that, using the brushless direct current motor instead of the synchronous one, the consumption of active electrical energy is reduced with 11.8%, and the machine weight is reduced with 12.7%.