A comparative study of the winding type influence on the noise level of two-speed three-phase induction motors

The goal of this work is to present the study of the influence of the winding - double layer or single layer - to the global noise level of an induction motor. For this purpose, two variable speed induction motors have been studied, of the type M3AA 71 B2/4 manufactured by Electroprecizia S.A. Săcele, Romania, with Dahlander windings, star connected - for the low speed and double star connected - for the high speed. The motors are modelled from magnetic and mechanical point of view with finite element softwares. The noise-to-frequency characteristics have been determined by investigations in a semi-anechoic chamber.