Design Methodology of a Multifunctional Screw-Type Energy Converter

Abstract

This paper examines the method of designing a non-standard electric machine – a three-phase induction motor with a hollow solid rotor, on the surface of which the turns of the screw are located. Such an unusual design makes it possible to turn the main disadvantage of induction machines with a solid rotor, namely the heating of the rotor due to the effect of eddy currents, into an advantage. The heat from the rotor is transferred to the bulk material, which is mixed by the screw, for drying and reducing the moisture content. At the same time, only one device is used to perform three functions - mixing, drying, transportation of bulk material, which, due to the specified functional features, was called a multifunctional energy converter (MEC). The MFEC design method differs from conventional machines, because it takes into account the peculiarities of determining the parameters of a number of typical methods: an induction motor with a squirrel-cage rotor, an induction motor with a solid internal rotor, and an inductor. In the previous publications of the authors, the complex methodology of designing an induction motor with an external solid rotor was considered in detail, however, in view of the additional theoretical and experimental studies conducted, it needs to be clarified and adjusted. In addition, in this paper, the beginning of the design, the determination of the initial data and the main dimensions of the MFEC is performed in a different way. In particular, the overall dimensions of the MFEC are determined not by the sum of power spent on heating and mixing the material and internal losses in an induction machine (considering the efficiency and power factor), but by the required performance of the unit and the limit dimensions of the installation area. The paper proposes a new approach to determining the dimensions of the stator slot, considering the necessary area for the placement of conductors and the current density in the winding. This paper is one of several publications that aim to reveal the features of design and mathematical modeling of such an atypical class of electric machines as an induction motor with an external hollow solid rotor.