Comparison of optical and magnetic particle detection systems for detection of pitting damage in low speed hydraulic motors

Abstract

In this study two systems for detection of pitting damage in low speed hydraulic motors were compared. These systems were based on an optical particle detector and a magnetic plug respectively. The purpose of the comparison was to determine the relative effectiveness of two methods for detecting pitting damage in a low speed hydraulic motor. In order to do this extensive testing was conducted in Bosch Rexroth Mellansel AB laboratory in Mellansel, Sweden. In the course of the project two post-processing algorithms were developed to enable automatic triggering of alarms based on measurement values from the optical sensor. The optical sensor showed earlier indication of damage than the magnetic plug and the algorithms produced automatic alarms, but there was also a higher false alarm rate when using the optical sensor compared to the magnetic plug.