Abstract:As compared with traditional offline detection, online oil monitoring technology has the advantages of realtime, synchronization, continuity, and etc. Ultrasonic is of good realtime, high spatial resolution and strong penetration ability in oil, so the development of online ultrasonic wear debris monitoring technology is of great significance. A set of online oil wear debris monitoring system based on the principle of ultrasonic scattering was designed. The hardware system was consisted of ultrasonictesting card, industrial control computer (IPC), ultrasonic sensor, online oil temperature sensor, gear pump and other components. The program of the system was developed by Delphi. A lot of experiments were implemented on the equipment. The results show that the online monitoring system can monitor the number and size of oil wear debris perfectly in near realtime.