Method of designing asynchronous propulsion motors with given power factor

Abstract

The article considers the problem of improving the quality of electricity, in particular the power factor. The increased value of the power factor leads to decreasing the reactive component of the currents in the ship power network and, as a result, to a decreased power of converting equipment, generators and cable products. There is studied 
 a section in the methodology of designing ship electrical machines developed at the Department of Electric Drives and Electrical Equipment of Coastal Power Plants in Admiral Makarov State University of Maritime and Inland Shipping, which allows to evaluate the parameters of asynchronous electric motors at the design stage. Today, in designing electrical machines there are used the methods developed in the last century, which do not allow to carry out electromagnetic calculations subject to the required value of the power factor. The power factor is known to be determined by empirical formulas after setting the main parameters of the mechanism. The equivalent circuit of asynchronous electric motor containing the parameters of stator and rotor windings, and its mathematical description based on equations corresponding to Kirchhoff's laws are considered. Transformations of the equations describing the electromagnetic processes in the engine given for the static mode of operation in a complex form are made. There are given the expressions that allow determining the magnetizing current, magnetic conductivities, magnetizing forces, air gap and magnetic saturation coefficients, overall dimensions of the electric motor, and electromagnetic torque that it develops. Basing on the transformed equations describing an asynchronous electric motor there have been derived the regularities that help set the value of the power factor as initial data at the stage of design. The practical significance of the applied methodology and importance of the chosen subject have been analyzed.