IEC 60034-9 Ed. 5.0 b:2021

This part of IEC 60034:

- specifies test methods for the determination of sound power level of rotating electrical machines;

- specifies maximum A-weighted sound power levels for factory acceptance testing of network-supplied, rotating electrical machines in accordance with lEC 60034-1, having methods of cooling according to lEC 60034-6 and degrees of protection according to lEC 60034-5, and having the following characteristics:

 standard design, either AC or DC, without additional special electrical, mechanical, or acoustical modifications intended to reduce the sound power level

 rated output from 1 kW (or kVA) up to and including 5 500 kW (or kVA)

 rated speed not greater than 3 750 min-1

Excluded are noise limits for AC motors supplied by converters. For these conditions see Annex B for guidance.

The object of this document is to determine maximum A-weighted sound power levels, LWA in decibels, dB, for airborne noise emitted by rotating electrical machines of standard design, as a function of power, speed and load, and to specify the method of measurement and the test conditions appropriate for the determination of the sound power level of the machines to provide a standardized evaluation of machine noise up to the maximum specified sound power levels. This document does not provide correction for the existence of tonal characteristics.

Sound pressure levels at a distance from the machine may be required in some applications, such as hearing protection programs. Information is provided on such a procedure in Clause 7 based on a standardized test environment.

NOTE 1 This document recognizes the economic reason for the availability of standard noise-level machines for use in non-critical areas or for use with supplementary means of noise attenuation.

NOTE 2 Where sound power levels lower than those specified in Table 1, Table 2 or Table 3 are required, these are agreed between the manufacturer and the purchaser, as special electrical, mechanical, or acoustical design may involve additional measures.