The necessity of the primary transformers rapidly increases due to the fast development of the microprocessing automated control systems and operation of the railway transport power supply devices, transferring to the flexible automated output. These transformers, besides high metrology characteristics, have to be highly reliable, have a wide range of change, stability, little dimensions.
The article is devoted to the development of methods for calculating magnetic circuits of current converters taking into account the nonlinearity of magnetic characteristics. At the same time, magnetic systems of current converters are of great interest, which, according to the principle of their operation, are magnetized simultaneously by constant and alternating magnetic fields (magnetomodulation converters). Analytical expressions of the magnetization curves of magnetic materials are proposed, experimental schemes are presented, and the feasibility of using a combination of oscillographic and wattmeter methods, the convergence of the calculated and experimental data are shown.
In article are brought frequency regulation of the asynchronous electric motor and that reach to energy saving itself. Frequency management is energy saving so regulation of the frequency of the rotation of the asynchronous engine are provided increasing coefficient of efficiency and reduction of the loss to powers. A machine asynchronous is often used today as a power scale ranging with a motor from some Watts to several thousand kW. For power applications exceeding several kW, asynchronous motors run solely on three-phase AC power supplies. Owing to the sensitivity of a process or the critical nature of certain applications, the network may be supported with an Uninterruptible Power Supply.
The city of Tashkent is developing at a very fast pace, and the power supply of a new type is the subject of innovation in this direction. Commercial metering of electricity in multi-storey buildings in modern cities mainly solves the current payment problems for consumed electricity. And the main disadvantages of such networks will remain overboard. Technically competently control the common highway of a multi-storey building is necessary. Here, the commercial metering of electricity consumption does not solve the technical policy considering the development of the city. The construction of multi-storey buildings based on an individual project is growing rapidly in the city. Together with the environmental aspects of the impact of such buildings, it is necessary to address the issue of reliability in power supply. The use of power supply schemes taking into account backup power is relevant. It is proposed to take a diesel power plant as a backup source. For this, an electrical circuit of relay protection using an automatic transfer switch is proposed.
During a long shutdown of the motors, the insulation quality of the windings of asynchronous motors deteriorates due to moisture. This requires additional costs for drying the insulation of electrical machines. The signs and possible causes of malfunctions of electrical machines, as well as methods of drying insulation, are studied: Drying by external heating, Drying by heating from an external source, Convective drying, Drying by induction loss, drying using light emitters. Drying using infrared radiation is the mildest method and helps to maintain the quality of the insulation. The movement of moisture in the layers of insulating windings occurs according to the laws of heat-mass exchange, that is, heat and moisture are simultaneously transferred. In this case, heat is transferred from more heated layers to less heated layers and at the same time promotes moisture transfer. A physical and electronic model was developed to study the effect of infrared radiation on the drying process of insulation of electrical machines. The main factors influencing the process under consideration are the power of the radiation sources and the supply voltage, that is, the temperature changes in the layers of the insulated windings were studied depending on the change in the power of the emitters and the supply voltage. The created model was investigated according to the main features corresponding to the real process (even the geometrical dimensions coincide). An indispensable condition for physical modeling is the strict geometric similarity of the model and nature, as well as the equality of the corresponding similarity criteria in them.
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