Models and Methods of Designing Linear Electric Motors for Non-Ferrous Metals Industry Applications

Abstract

Through substitution of rotating induction motor drives with linear ones, one can enhance the reliability and decrease the materials capacity of electrical equipment utilized by the non-ferrous metals industry. At the same time, each particular case requires a feasibility study to justify the application of the linear induction motor. Such feasibility study is based on the key technical data of the unit obtained through mathematical modelling. The authors carried out an analysis of the existing linear induction motor models. The aim of this research is to develop a number of analytical design models. This paper looks at flat double-sided linear induction motors with a short and long secondary element. Possible applications are described for such linear induction motors in the non-ferrous metals industry. A design approach and a mathematical model were developed to calculate the magnetic vector potential and the pull force of the linear induction motor with a long secondary element. An accurate solution for the magnetic vector potential was found through Fourier transformation, which, together with the expression for the pull force, provides a design model of the motor. The model parameters were chosen based on the desired mechanical performance of the motor. A linear induction motor with a long secondary element was designed for the force of 1,000 N and the speed of 2–3 m/sec. The paper describes the modelling results, as well as the technical data of the motor. Alternative design models of the motor were compared. The authors describe a design approach and a mathematical model for calculating the magnetic vector potential and the pull force of the linear induction motor with a short secondary element. The Bubnov-Galerkin method was used to find an approximate solution for the magnetic vector potential. On the basis of that solution, a linear induction motor with a short secondary element was designed for the force of 528 N and the speed of 2–3 m/sec. This paper describes some economic aspects related to the adoption of linear induction motors. It is pointed out that the low probability of failure characteristic of linear induction motors helps lower the losses related to the emergency shutdowns and unscheduled maintenance. It is also associated with lower redundancy costs.This research was funded by the Russian Foundation for Basic Research in the framework of the Research Project No. 20-01-00283.