Investigation and Comparison of Three-Phase and Six-Phase Cage Motor Energy Parameters

Abstract

Factory-produced three-phase 2,2 kW power cage motor with single-layer preformed winding and the same motor after its original winding was replaced with a single-layer preformed six-phase winding was investigated in this work. Electromagnetic properties of the stator windings of the analyzed motors were determined after performing the harmonic analysis of their generated rotating magnetomotive forces and by calculating the electromagnetic efficiency factors according to the results of this analysis. Electromagnetic efficiency factors of both single-layer preformed three-phase, and six-phase windings are equal under the same pole count but unequal number of pole and phase slots (k_ef = 0,914). All energy parameters of factory-made cage motor and rewound motor were calculated after completing their no-load and load tests and by using the segregated-losses method. It was estimated that under the rated load the phase electric current of rewound cage motor with six-phase stator winding decreased by 16,4 %, power input from electric grid decreased by 4,4 %, power losses decreased by 13,5 %, efficiency factor increased by 3,8 %, and power factor increased by 4,7 %, compared to identically loaded factory-made cage motor with respective energy parameters. Research has shown that energy parameters of the six-phase cage motor are noticeably better compared to the three-phase motor, even though the electromagnetic efficiency factors of their windings were equal.

DOI: http://dx.doi.org/10.5755/j01.eee.21.3.5876