The Magnetic Noise of Three-Phase Induction Motors with Squirrel Cage Rotors

Abstract

In this paper a study of the magnetic noise in three-phase one and two-speed cage rotor, totally enclosed, externally cooled induction motors is presented. Investigations include two-speed three-phase induction motors with Dahlander winding connection or separate windings, with rated speeds of 3000/1500 rpm, 1500/750 rpm, 1500/1000 rpm. The investigated motors (manufactured by SC Electroprecizia SA) were placed in a semi-anechoic chamber in order to determine the noise versus frequency characteristics (spectrograms). The paper is based on results and conclusions obtained after analyzing these spectrograms. The importance of the pressure applied by the stacking of the stator laminations for the level of the magnetic noise is also presented.

The magnetic noise of inverter-fed three-phase induction motors with squirrel cage rotors

“…The subject presents theoretical and practical importance as it results from the solutions proposed in the most recent literature [1,2]. This paper is one of a series of other papers [3,4,5,6,7] in which the authors deal with the problem of noise in electric motors. Each of these sources [5,6,7,8] determines a particular type of noise (of aerodynamic, mechanical, magnetic nature).…”

“…This paper is one of a series of other papers [3,4,5,6,7] in which the authors deal with the problem of noise in electric motors. Each of these sources [5,6,7,8] determines a particular type of noise (of aerodynamic, mechanical, magnetic nature). The investigated motors were mounted in a semi-anechoic chamber in order to determine the noise-to-frequency characteristics.…”

Optimal Slot Numbers for Magnetic Noise Reduction in Variable-Speed Induction Motors

“…However, no general rule can be inferred from these few FEM computations, and they are too computationally greedy to be used at the design stage of the motor to choose the quietest slot numbers combination. Finally, [10] made a recent exhaustive experimental study on the influence of slot numbers on acoustic noise of two-speed induction machines, and proposes a list of low-noise rules of thumb without any theoretical basis, without specifying which are the natural frequencies of the studied motor. Note that a similar issue is encountered in the field of switched reluctance machines for the choice of the stator and rotor numbers of poles, although some analytical models of the electromagnetic and vibroacoustic behavior have been already established [11].…”