Abstract
Acoustic diagnosis system with condenser microphone has some attractive characters what is more cheap for cost of devices of sensor, is not keeping contact with machinery components and is wide band range on frequency compare with piezoelectric accelerometers. This paper proposes a method to do condition diagnosis about non stationary signal generated by operating rotary machineries which are a rolling bearing. Especially, a signal processing technique in order to eliminate non stationary noises including operating sound is described by adopting locally stationary AR model a kind of system identification. Further, the optimum order of locally stationary AR model is determined from presumption of division terms. The effectiveness of this method has been identified by experimentation based on a rotary simulator device on a rolling bearing.
