Combined lubrication monitor for on-line gearbox health assessment

Lubricant condition monitoring is widely recognized as an effective means to determine the health of gearboxes and drive train components.12 For example, in rotorcraft systems, where the health of drive train and engine systems is paramount for safe operation and readiness, a staple means of condition monitoring of legacy gearboxes has been the use of both offline oil analysis and chip detection sensors, primarily because of their effectiveness in detecting both potential and actual sources of mechanical degradation in the oil. However, the challenges associated with these types of separate monitoring activities, including the high cost and complex logistical burden laid upon systems or aircraft in service, and their information and detection timing limitations, make an online monitoring technology for gearbox lubricant condition and debris detection highly desirable. To this end, Impact Technologies, LLC is developing an integrated online monitoring system capable of both real-time oil condition monitoring as well as ferrous and non-ferrous metallic debris detection. This innovative system integrates two separate technologies into a single device to better meet performance demands for lubricant-based health monitoring of high performance gearboxes and drive trains. This paper describes the benefits of the combined technologies and outlines efforts and lessons learned during the design process to achieve high fidelity and reliability in a tightly packaged, lightweight and robust mechanical and electronic design resistant to vibration and thermal exposure. The paper also discusses key monitoring capabilities as well as system validation, testing and performance characterization for such relevant technology.