Basic sound level knowledge for electric motor application

The sound emitted from industrial electric motors can adversely affect the comfort and safety of those who work in their vicinity. As such, many customers and governing agencies impose strict sound limitations on motors placed in audibly sensitive applications. This paper will explore the nature of sound data, how it is measured, and interpreted. Topics will include the decibel, differences between sound power and sound pressure, along with octave bands and various weightings. The equipment and procedures necessary for reliable sound data acquisition will be reviewed. Causes and mitigation methods of sound within electric motors will be discussed. Finally, applicable industry specifications will be compared to give a sample of standards that provide guidance to users in this area.