Sound Level Analysis
Sound is composed simply of vibrations traveling through air. Analyzing sound using a microphone, rather than a vibration transducer, helps acquire vital information about the condition of a piece of equipment.
Although sound level analysis testing is easier to perform than vibration analysis, it is a step removed from the source of trouble. However, sound level analysis should play a role in a comprehensive predictive maintenance program.
By itself, sound does not indicate a piece of equipment is beginning to fail. Tracing the sound to a particular point and comparing it to the normal sound level will help establish an accurate diagnosis. Any person familiar with the apparatus may be able to detect a change in that equipment’s noise level, but measuring the sound using instruments will help quantify any changes over time.
Frequency measurement devices accurately diagnose sound. For example, a wear problem may be indicated if the amplitude of a gear mesh increases in frequency. Bearing failure generates a distinctive frequency along with specific signals indicating problems.
Knowing the frequency derived from its sources assists with analysis in regard to reflecting, absorbing, or circulating the energy of the sound wave. Knowing the location of the sound source in relation to the geometry of the area helps render an accurate sound level analysis.