Asynchronous motors with six and more phases (usually n-three-phase) are increasingly accepted in electric drive systems of road transport, marine and even aeronautical transport. Multiphase machines are credited with multiple advantages such as: less torque ripple, better power distribution per phase, higher efficiency and fault tolerance capability compared to traditional three-phase machines. There are many publications, but few of them are dedicated to the in-depth study of the multiphase motor (m>3) and especially of the magnetic field in its air gap. The purpose of the present paper: the development of the mathematical model of the magnetomotive force in the air gap of the six-phase asynchronous machines, which determines the fundamental properties of the machine, the structure of the magnetic field and the torque developed, the efficiency, the error tolerance. The research is based on analytical studies and the results of suitable experimental measurements. The paper presents the mathematical model for the harmonic analysis of the magnetomotive force in the air gap of six-phase machines with possible variants of windings on the stator. Based on this study, it was demonstrated that only n-three-phase machines with asymmetrically arranged stator windings have the ability to attenuate higher harmonics with a major negative effect on the developed torque, the applicability and efficiency of traditional tools for reducing higher harmonics in the case of six-phase machines was confirmed. The results of measurements carried out on samples of six-phase machines confirm the findings and conclusions formulated in the paper.

This paper proposes a solution for carrying out laboratory work in the strict conditions of the Covid - 19 pandemic. The traditional laboratory can be replaced by the virtual laboratory or the remote laboratory, depending on the requirements of the course and the skills required for the training of engineers. The environment for performing alternative laboratory work (Virtual or Remote Laboratory) is the Multisim software from National Instruments. The student with the help of this software can make the electrical circuits provided in the curriculum of the discipline of General Electrical Engineering. This paper presents four examples of alternative laboratory works for the field of electrical engineering, namely, three-phase electrical circuits, static electrical converters, asynchronous motor and electric drive system. The student can simulate the required regimes in the laboratory guide and is free to simulate other regimes at his own initiative. The paper ends with the proposal of a step-by-step algorithm, which can be a guide for any teacher who wants to organize alternative laboratory work.

This paper presents a comparative study of several six-phase winding configurations, evaluated both through analytical calculations and a graphical assessment method based on the MMF diagram. The mathematical approach involves determining the winding quality factor for each configuration, taking into account the distribution of the magnetomotive force along the air gap, as well as the winding distribution and pitch factors. The graphical method provides a visual interpretation of winding performance, facilitating direct comparison between configurations, as well as highlighting practical engineering applications. The paper presents examples of basic topological structures of single-layer, double-layer, bipolar, and multipolar windings for the development of homologous series of six-phase induction machines. Both the nominal operating mode and operation under fault conditions are examined. The results enable the classification of winding variants into a quality-based hierarchy, offering valuable recommendations for selecting winding topologies in the design of high-performance six-phase machines. This combined analytical-graphical approach supports both theoretical research and practical engineering applications.

The paper presents the development and implementation of an automated testing stand designed for analyzing the performance of traction electric motors. The proposed system uses the NI cRIO-9057 platform with modular extension boards, in combination with industrial voltage, current, and torque sensors. The software application was developed in the LabVIEW environment and includes a PC interface, synchronous data acquisition, and spectral analysis. Experimental results obtained on a three-phase asynchronous motor validate the full functionality of the test stand, providing a scalable solution for testing electric drive systems.

The main scope of this research was to complete and validate the analysis of stator winding topologies of six-phase AC machines using the winding quality factor by determining fault tolerance and validating it through experimental tests. This paper proposes a unified and practical methodology for evaluating the performance of stator windings in six-phase induction machines, with emphasis on magnetic field quality and fault-tolerant operation. The approach combines analytical modeling of the magnetomotive force (MMF) with its graphical representation using the MMF polygon, enabling an efficient assessment of harmonic content through a global indicator, referred to as the winding quality factor. Several representative winding topologies are analyzed within a common framework, including single-layer and double-layer configurations with full-pitch and short-pitch coils, suitable for generating homologous series of six-phase machines. The study considers both normal operating conditions and post-fault regimes, particularly operation with a single three-phase set. The results reveal the strong influence of winding topology on harmonic distortion and overall machine performance, highlighting the trade-offs between magnetic field quality and fault tolerance. It is shown that appropriate winding design can reduce spatial harmonics and improve robustness under degraded operating conditions. The theoretical findings are validated through experimental investigations, demonstrating good agreement between analytical predictions and measured data. A parallel analysis was performed between the theoretical findings and experimental data, and the results conform to the authors’ expectations.