Noise Test on Rotating Electrical Motors Under Load

ABSTRACT

The noise of the rotating electrical motor can be strongly influenced by the change in the loading conditions. In extreme cases a noise component of electromagnetic origin may increase by 36 dB or decrease by 24 dB upon loading.Protection of a human being from the noise depends on the noise characteristics of the el. machine under operating conditions. The standards relevant to the noise qualification measurements permit the use of the sound power level determined under no–load conditions, if the noise of the machine does not vary with the change in the load. This is a concession that is made because it is difficult to separate the noise level of the loading machine from the noise of the electric motor being investigated. This paper presents several methods, and their analyses, where the sound power level emitted by a loaded electrical motor can be determined experimentally in an industrial environment.Wide ranging experimental work has been made in this field, which will be be presented at the end of the paper.