Quantification of condition indicator performance on a split torque gearbox

The requirement for higher energy density transmissions (lower weight) in helicopters has lead to the development of the Split Torque Gearbox (STG) to replace the traditionally planetary gearbox by the drive drain designer. This may pose a challenge for the current gear analysis methods used in Health and Monitoring Systems (HUMS). Gear analysis uses time synchronous averages to separates in frequency gears that are physically close to a sensor. The effect of a large number of synchronous components (gears or bearing) in close proximity may significantly reduce the fault signal (increase signal to noise) and therefore reduce the effectiveness of current gear analysis algorithms. In this study, we developed a STG for testing in order to generate a no fault and single gear fault date sets of vibration data. These vibration signatures are processed through the a number of gear analysis algorithms (see Table 1, 2 and 3) to quantify performance. The performance metric was separablity. Additionally, advance signal processing techniques where developed in order to potentially improve separability.