Noise change as an indicator of maintenance requirement

Machine malfunction may be detected from the change in its noise level sensed by the ear or measured by a sound level meter. When various machines run concurrently in a workshop, it is not easy to detect noise change. This paper presents the development of a system of equations relating to the combined noise level at each machine with the individual noise level and the intermachine distances. A method is presented to detect a malfunctioned machine by solving a system of equations and a case study is included.