Lithuanian University of Agriculture
In the paper the standard dimensioned 1,5 kW three-phase induction motor with single-layer former winding and the same motor with stator winding replaced with sinusoidal winding was analyzed. Electromagnetic features of stator windings of the considered motors were evaluated on the base of harmonic analysis of rotating magnetomotive forces created by them and by calculating electromagnetic efficiency factors on the base of the analysis results. It was determined that the electromagnetic efficiency factor of the single-layer former three-phase winding kef1 = 0,9139, and for sinusoidal three-phase winding – kef2 = 0,9335, i. e. by 2,14 % higher than the factor of the first winding. All power indexes of standard dimensioned induction motor with single-layer winding and of motor with stator winding replaced with sinusoidal three-phase winding were calculated after completing no-load and load tests of the motor and by applying the segregated-losses method. It was found that the phase current of the induction motor with stator winding replaced with sinusoidal three phase winding under indicated load decreased by 6,9 % , power taken from electric grid decreased by 5,0 %, power losses decreased by 11,7 %, efficiency factor increased by 2,4 % and power factor increased by 3,4 % compare to the respective power indexes of the standard dimensioned induction motor under the same load. It was determined that induction motor with three-phase winding of higher electromagnetic efficiency factor also has better power indexes. Ill. 4, bibl. 5, tabl. 8 (in English; abstracts in English, Russian and Lithuanian).