Test-Based Analysis of Fault Tolerance Capability of Six-Phase Asynchronous Motors

Six-phase asynchronous motors are becoming increasingly popular in transport and industrial applications due to their advantages such as less torque ripple, better power distribution between the phases, higher efficiency, and increased tolerance capability errors compared to three-phase ones. This paper presents an analysis, primarily based on the results of experimental tests but also on theoretical arguments, of the natural fault tolerance capacity of an asynchronous motor (induction machines) in six phases with symmetrical and asymmetrical windings. The degree of tolerance is examined, defined as the ability of the machine to create a starting and overload torque and to withstand operation for a certain period of time without danger to the integrity and reduction of the life resource of the insulation. A matrix of tolerance rating is defined regarding the operation of the motor on loss of supply on one, two or three phases in different sequences.