This part of IEC 60034 specifies maximum A-weighted sound power levels for factory acceptance testing of rotating electrical machines in accordance with IEC 60034-1, having methods of cooling according to IEC 60034-6 and degrees of protection according to IEC 60034-5, and having the following characteristics:
- standard design, either a.c. or d.c, without additional special electrical, mechanical, or acoustical modifications intended to reduce the noise level;
- rated output from 1 kW (or kVA) up to and including 5 500 kW (or kVA);
- speed not greater than 3 750 min.
Excluded are a.c. motors supplied by convenors. For these conditions see IEC 60034-17 for guidance.
NOTES
1 This standard 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.
2 Where noise levels lower than those specified in tables 1 or 2 are required, these should be agreed between the manufacturer and the purchaser, as special electrical, mechanical, or acoustical design may involve additional cost.
The object of this standard 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 standard 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. However, this standard is only concerned with the physical aspect of noise, to express limits in terms of sound power. In situ sound pressure calculations require knowledge of machine size, operating conditions and the environment in which the machine is to be installed. Information for such calculations taking into account environmental factors can be found, if needed, in classical textbooks on acoustics.