Calculation of parameters of a linear asynchronous motor for a melt mixing system
A set of questions on the modeling of electromagnetic processes in a linear asynchronous motor, which is a system containing a stator winding, a steel furnace body and a molten metal, is considered. Effective mixing of the liquid metal is realized in a single-phase power supply mode of the stator winding. For the linear movement of the melt, which is required when slag is charged, two-phase voltage is used. The calculation of the controlled field of electromagnetic forces, providing the circulation and linear displacement regimes, was carried out numerically. The large gap between the stator and the melt and the presence of a steel shell between them lead to low values of efficiency and power factor. The search for a favorable relationship between the width of the groove and the tooth is made taking into account the restrictions on the allowable values of induction in the magnetic circuit, heat loss and voltage in the stator winding. The complexity of the geometric design makes it difficult to use the procedures built in the calculation program for finding the optimal parameters of the designed device. The presence of ferromagnetic materials in the stator design causes a complex relationship in the distribution of electromagnetic fields and heat sources inside the shell. Analysis of heat losses at the edges of the stator winding led to the need to reduce the size of the conductor due to the significant uneven distribution of current. The choice of the frequency of the voltage produced on the basis of a comparison of the nature of the movement of the melt under the action of electromagnetic forces. High-quality mixing is achieved when large vortices are formed that capture the entire lower layer of the melt, which is ensured by increasing the stator length. In the download mode, the formation of two layers in the melt, moving towards each other, is beneficial. The calculations showed a linear dependence of many parameters of a linear motor on the ratio of the width of the tooth and the groove for the region of unsaturated iron of the magnetic circuit.